• dr hab. Agata Burian
Stanowisko: Profesor Uczelni
Jednostka: Wydział Nauk Przyrodniczych
Adres: 40-032 Katowice, ul. Jagiellońska 28
Piętro: III
Numer pokoju: C-345
Telefon: (32) 2009 572
E-mail: agata.burian@us.edu.pl
Spis publikacji: Spis wg CINiBA
Spis publikacji: Spis wg OPUS
Scopus Author ID: 15055446300
Publikacje z bazy Scopus
2025
Lapointe, B. P.; Kaur, N. S.; Routier-Kierzkowska, A. L.; Burian, A.
From stress to growth: Mechanical tissue interactions in developing organs Journal Article
In: Current Opinion in Plant Biology, vol. 86, 2025, (2).
@article{2-s2.0-105010294963,
title = {From stress to growth: Mechanical tissue interactions in developing organs},
author = { B.P. Lapointe and N.S. Kaur and A.L. Routier-Kierzkowska and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105010294963&doi=10.1016%2fj.pbi.2025.102759&partnerID=40&md5=016ad001baf7ce10163324c370a2dec0},
doi = {10.1016/j.pbi.2025.102759},
year = {2025},
date = {2025-01-01},
journal = {Current Opinion in Plant Biology},
volume = {86},
publisher = {Elsevier Ltd},
abstract = {Plant cells usually grow in a coordinated manner due to rigid cell wall connections. However, individual tissue layers may differ in their growth capacity or elastic properties, creating tissue-level mechanical stresses. While mechanical forces are recognized as a key factor controlling growth and organ posture, the origin and exact patterns of tissue stresses in different organs remain unclear. This review synthesizes current knowledge of tissue mechanics in stems, roots, and leaves, emphasizing stress pattern changes during development, their potential causes, and the tissue-specific regulation of organ growth. © 2025 The Author(s)},
note = {2},
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Plant cells usually grow in a coordinated manner due to rigid cell wall connections. However, individual tissue layers may differ in their growth capacity or elastic properties, creating tissue-level mechanical stresses. While mechanical forces are recognized as a key factor controlling growth and organ posture, the origin and exact patterns of tissue stresses in different organs remain unclear. This review synthesizes current knowledge of tissue mechanics in stems, roots, and leaves, emphasizing stress pattern changes during development, their potential causes, and the tissue-specific regulation of organ growth. © 2025 The Author(s)
2024
Yu, Le.; Renton, J.; Burian, A.; Khachaturyan, M.; Bayer, T.; Kotta, J.; Stachowicz, J. J.; DuBois, K.; Baums, I. B.; Werner, B.; Reusch, T. B. H.
A somatic genetic clock for clonal species Journal Article
In: Nature Ecology and Evolution, vol. 8, no. 7, pp. 1327-1336, 2024, (6).
@article{2-s2.0-85195449730,
title = {A somatic genetic clock for clonal species},
author = { Le. Yu and J. Renton and A. Burian and M. Khachaturyan and T. Bayer and J. Kotta and J.J. Stachowicz and K. DuBois and I.B. Baums and B. Werner and T.B.H. Reusch},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85195449730&doi=10.1038%2fs41559-024-02439-z&partnerID=40&md5=4ea95a937afff65afad1a0e061d76049},
doi = {10.1038/s41559-024-02439-z},
year = {2024},
date = {2024-01-01},
journal = {Nature Ecology and Evolution},
volume = {8},
number = {7},
pages = {1327-1336},
publisher = {Nature Research},
abstract = {Age and longevity are key parameters for demography and life-history evolution of organisms. In clonal species, a widespread life history among animals, plants, macroalgae and fungi, the sexually produced offspring (genet) grows indeterminately by producing iterative modules, or ramets, and so obscure their age. Here we present a novel molecular clock based on the accumulation of fixed somatic genetic variation that segregates among ramets. Using a stochastic model, we demonstrate that the accumulation of fixed somatic genetic variation will approach linearity after a lag phase, and is determined by the mitotic mutation rate, without direct dependence on asexual generation time. The lag phase decreased with lower stem cell population size, number of founder cells for the formation of new modules, and the ratio of symmetric versus asymmetric cell divisions. We calibrated the somatic genetic clock on cultivated eelgrass Zostera marina genets (4 and 17 years respectively). In a global data set of 20 eelgrass populations, genet ages were up to 1,403 years. The somatic genetic clock is applicable to any multicellular clonal species where the number of founder cells is small, opening novel research avenues to study longevity and, hence, demography and population dynamics of clonal species. © The Author(s) 2024.},
note = {6},
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Age and longevity are key parameters for demography and life-history evolution of organisms. In clonal species, a widespread life history among animals, plants, macroalgae and fungi, the sexually produced offspring (genet) grows indeterminately by producing iterative modules, or ramets, and so obscure their age. Here we present a novel molecular clock based on the accumulation of fixed somatic genetic variation that segregates among ramets. Using a stochastic model, we demonstrate that the accumulation of fixed somatic genetic variation will approach linearity after a lag phase, and is determined by the mitotic mutation rate, without direct dependence on asexual generation time. The lag phase decreased with lower stem cell population size, number of founder cells for the formation of new modules, and the ratio of symmetric versus asymmetric cell divisions. We calibrated the somatic genetic clock on cultivated eelgrass Zostera marina genets (4 and 17 years respectively). In a global data set of 20 eelgrass populations, genet ages were up to 1,403 years. The somatic genetic clock is applicable to any multicellular clonal species where the number of founder cells is small, opening novel research avenues to study longevity and, hence, demography and population dynamics of clonal species. © The Author(s) 2024.
Chen, Yi.; Burian, A.; Johannes, F. M.
Somatic epigenetic drift during shoot branching: a cell lineage-based model Journal Article
In: Genetics, vol. 227, no. 4, 2024, (3).
@article{2-s2.0-85200939146,
title = {Somatic epigenetic drift during shoot branching: a cell lineage-based model},
author = { Yi. Chen and A. Burian and F.M. Johannes},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85200939146&doi=10.1093%2fgenetics%2fiyae091&partnerID=40&md5=fa29169c3a596acda3aa9367dbba9b1f},
doi = {10.1093/genetics/iyae091},
year = {2024},
date = {2024-01-01},
journal = {Genetics},
volume = {227},
number = {4},
publisher = {Oxford University Press},
abstract = {Plant architecture is shaped by the production of new organs, most of which emerge postembryonically. This process includes the formation of new lateral branches along existing shoots. Current evidence supports a detached-meristem model as the cellular basis of lateral shoot initiation. In this model, a small number of undifferentiated cells are sampled from the periphery of the shoot apical meristem (SAM) to act as precursors for axillary buds, which eventually develop into new shoots. Repeated branching thus creates cellular bottlenecks (i.e. somatic drift) that affect how de novo (epi)genetic mutations propagate through the plant body during development. Somatic drift could be particularly relevant for stochastic DNA methylation gains and losses (i.e. spontaneous epimutations), as they have been shown to arise rapidly with each cell division. Here, we formalize a special case of the detached-meristem model, where precursor cells are randomly sampled from the SAM periphery in a way that maximizes cell lineage independence. We show that somatic drift during repeated branching gives rise to a mixture of cellular phylogenies within the SAM over time. This process is dependent on the number of branch points, the strength of drift as well as the epimutation rate. Our model predicts that cell-to-cell DNA methylation heterogeneity in the SAM converges to nonzero states during development, suggesting that epigenetic variation is an inherent property of the SAM cell population. Our insights have direct implications for empirical studies of somatic (epi)genomic diversity in long-lived perennial and clonal species using bulk or single-cell sequencing approaches. © The Author(s) 2024.},
note = {3},
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pubstate = {published},
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}
Plant architecture is shaped by the production of new organs, most of which emerge postembryonically. This process includes the formation of new lateral branches along existing shoots. Current evidence supports a detached-meristem model as the cellular basis of lateral shoot initiation. In this model, a small number of undifferentiated cells are sampled from the periphery of the shoot apical meristem (SAM) to act as precursors for axillary buds, which eventually develop into new shoots. Repeated branching thus creates cellular bottlenecks (i.e. somatic drift) that affect how de novo (epi)genetic mutations propagate through the plant body during development. Somatic drift could be particularly relevant for stochastic DNA methylation gains and losses (i.e. spontaneous epimutations), as they have been shown to arise rapidly with each cell division. Here, we formalize a special case of the detached-meristem model, where precursor cells are randomly sampled from the SAM periphery in a way that maximizes cell lineage independence. We show that somatic drift during repeated branching gives rise to a mixture of cellular phylogenies within the SAM over time. This process is dependent on the number of branch points, the strength of drift as well as the epimutation rate. Our model predicts that cell-to-cell DNA methylation heterogeneity in the SAM converges to nonzero states during development, suggesting that epigenetic variation is an inherent property of the SAM cell population. Our insights have direct implications for empirical studies of somatic (epi)genomic diversity in long-lived perennial and clonal species using bulk or single-cell sequencing approaches. © The Author(s) 2024.
Scacchi, E.; Paszkiewicz, G.; Nguyen, K. Thi; Meda, S.; Burian, A.; de Back, W.; Timmermans, M. C. P.
A diffusible small-RNA-based Turing system dynamically coordinates organ polarity Journal Article
In: Nature Plants, vol. 10, no. 3, pp. 412-422, 2024, (5).
@article{2-s2.0-85185921143,
title = {A diffusible small-RNA-based Turing system dynamically coordinates organ polarity},
author = { E. Scacchi and G. Paszkiewicz and K. Thi Nguyen and S. Meda and A. Burian and W. de Back and M.C.P. Timmermans},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85185921143&doi=10.1038%2fs41477-024-01634-x&partnerID=40&md5=b3a4d30b97634e8eb13c0be9bfa70cf7},
doi = {10.1038/s41477-024-01634-x},
year = {2024},
date = {2024-01-01},
journal = {Nature Plants},
volume = {10},
number = {3},
pages = {412-422},
publisher = {Nature Research},
abstract = {The formation of a flat and thin leaf presents a developmentally challenging problem, requiring intricate regulation of adaxial–abaxial (top–bottom) polarity. The patterning principles controlling the spatial arrangement of these domains during organ growth have remained unclear. Here we show that this regulation in Arabidopsis thaliana is achieved by an organ-autonomous Turing reaction‐diffusion system centred on mobile small RNAs. The data illustrate how Turing dynamics transiently instructed by prepatterned information is sufficient to self‐sustain properly oriented polarity in a dynamic, growing organ, presenting intriguing parallels to left–right patterning in the vertebrate embryo. Computational modelling demonstrates that this self-organizing system continuously adapts to coordinate the robust planar polarity of a flat leaf while affording flexibility to generate the tissue patterns of evolutionarily diverse organ shapes. Our findings identify a small-RNA-based Turing network as a dynamic regulator of organ polarity that accounts for leaf shape diversity at the level of the individual organ, plant or species. © The Author(s), under exclusive licence to Springer Nature Limited 2024.},
note = {5},
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pubstate = {published},
tppubtype = {article}
}
The formation of a flat and thin leaf presents a developmentally challenging problem, requiring intricate regulation of adaxial–abaxial (top–bottom) polarity. The patterning principles controlling the spatial arrangement of these domains during organ growth have remained unclear. Here we show that this regulation in Arabidopsis thaliana is achieved by an organ-autonomous Turing reaction‐diffusion system centred on mobile small RNAs. The data illustrate how Turing dynamics transiently instructed by prepatterned information is sufficient to self‐sustain properly oriented polarity in a dynamic, growing organ, presenting intriguing parallels to left–right patterning in the vertebrate embryo. Computational modelling demonstrates that this self-organizing system continuously adapts to coordinate the robust planar polarity of a flat leaf while affording flexibility to generate the tissue patterns of evolutionarily diverse organ shapes. Our findings identify a small-RNA-based Turing network as a dynamic regulator of organ polarity that accounts for leaf shape diversity at the level of the individual organ, plant or species. © The Author(s), under exclusive licence to Springer Nature Limited 2024.
Burian, A.; Kierzkowski, D.
Unravelling the internal connections of plants Journal Article
In: New Phytologist, vol. 243, no. 1, pp. 10-13, 2024, (0).
@article{2-s2.0-85189542229,
title = {Unravelling the internal connections of plants},
author = { A. Burian and D. Kierzkowski},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189542229&doi=10.1111%2fnph.19718&partnerID=40&md5=3eb4788221f77a32145c9637b6b24122},
doi = {10.1111/nph.19718},
year = {2024},
date = {2024-01-01},
journal = {New Phytologist},
volume = {243},
number = {1},
pages = {10-13},
publisher = {John Wiley and Sons Inc},
abstract = {[No abstract available]},
note = {0},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
[No abstract available]
2022
Burian, A.; Paszkiewicz, G.; Nguyen, K. T.; Meda, S.; Raczyńska-Szajgin, M.; Timmermans, M. C. P.
Specification of leaf dorsiventrality via a prepatterned binary readout of a uniform auxin input Journal Article
In: Nature Plants, vol. 8, no. 3, pp. 269-280, 2022, (33).
@article{2-s2.0-85126869916,
title = {Specification of leaf dorsiventrality via a prepatterned binary readout of a uniform auxin input},
author = { A. Burian and G. Paszkiewicz and K.T. Nguyen and S. Meda and M. Raczyńska-Szajgin and M.C.P. Timmermans},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126869916&doi=10.1038%2fs41477-022-01111-3&partnerID=40&md5=ca069807d3e0f8d4cce846ec133b5178},
doi = {10.1038/s41477-022-01111-3},
year = {2022},
date = {2022-01-01},
journal = {Nature Plants},
volume = {8},
number = {3},
pages = {269-280},
publisher = {Nature Research},
abstract = {Developmental boundaries play an important role in coordinating the growth and patterning of lateral organs. In plants, specification of dorsiventrality is critical to leaf morphogenesis. Despite its central importance, the mechanism by which leaf primordia acquire adaxial versus abaxial cell fates to establish dorsiventrality remains a topic of much debate. Here, by combining time-lapse confocal imaging, cell lineage tracing and molecular genetic analyses, we demonstrate that a stable boundary between adaxial and abaxial cell fates is specified several plastochrons before primordium emergence when high auxin levels accumulate on a meristem prepattern formed by the AS2 and KAN1 transcription factors. This occurrence triggers a transient induction of ARF3 and an auxin transcriptional response in AS2-marked progenitors that distinguishes adaxial from abaxial identity. As the primordium emerges, dynamic shifts in auxin distribution and auxin-related gene expression gradually resolve this initial polarity into the stable regulatory network known to maintain adaxial–abaxial polarity within the developing organ. Our data show that spatial information from an AS2–KAN1 meristem prepattern governs the conversion of a uniform auxin input into an ARF-dependent binary auxin response output to specify adaxial–abaxial polarity. Auxin thus serves as a single morphogenic signal that orchestrates distinct, spatially separated responses to coordinate the positioning and emergence of a new organ with its patterning. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.},
note = {33},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Developmental boundaries play an important role in coordinating the growth and patterning of lateral organs. In plants, specification of dorsiventrality is critical to leaf morphogenesis. Despite its central importance, the mechanism by which leaf primordia acquire adaxial versus abaxial cell fates to establish dorsiventrality remains a topic of much debate. Here, by combining time-lapse confocal imaging, cell lineage tracing and molecular genetic analyses, we demonstrate that a stable boundary between adaxial and abaxial cell fates is specified several plastochrons before primordium emergence when high auxin levels accumulate on a meristem prepattern formed by the AS2 and KAN1 transcription factors. This occurrence triggers a transient induction of ARF3 and an auxin transcriptional response in AS2-marked progenitors that distinguishes adaxial from abaxial identity. As the primordium emerges, dynamic shifts in auxin distribution and auxin-related gene expression gradually resolve this initial polarity into the stable regulatory network known to maintain adaxial–abaxial polarity within the developing organ. Our data show that spatial information from an AS2–KAN1 meristem prepattern governs the conversion of a uniform auxin input into an ARF-dependent binary auxin response output to specify adaxial–abaxial polarity. Auxin thus serves as a single morphogenic signal that orchestrates distinct, spatially separated responses to coordinate the positioning and emergence of a new organ with its patterning. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.
Kwiatkowska, D.; Burian, A.
Plant Biomechanics—A Natural Transition from Molecular to Organ Scale Book
MDPI, 2022, (2).
@book{2-s2.0-85133691617,
title = {Plant Biomechanics—A Natural Transition from Molecular to Organ Scale},
author = { D. Kwiatkowska and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133691617&doi=10.3390%2fijms23147575&partnerID=40&md5=a356f3e9e016fd01c6ce0b4d80c6d352},
doi = {10.3390/ijms23147575},
year = {2022},
date = {2022-01-01},
journal = {International Journal of Molecular Sciences},
volume = {23},
number = {14},
publisher = {MDPI},
abstract = {[No abstract available]},
note = {2},
keywords = {},
pubstate = {published},
tppubtype = {book}
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[No abstract available]
2021
Burian, A.; Raczyńska-Szajgin, M.; PaÅubicki, W.
Shaping leaf vein pattern by auxin and mechanical feedback Journal Article
In: Journal of Experimental Botany, vol. 72, no. 4, pp. 964-967, 2021, (6).
@article{2-s2.0-85104872405,
title = {Shaping leaf vein pattern by auxin and mechanical feedback},
author = { A. Burian and M. Raczyńska-Szajgin and W. PaÅubicki},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104872405&doi=10.1093%2fjxb%2feraa499&partnerID=40&md5=a5588b21c5d8918749ba8a8e08294c9a},
doi = {10.1093/jxb/eraa499},
year = {2021},
date = {2021-01-01},
journal = {Journal of Experimental Botany},
volume = {72},
number = {4},
pages = {964-967},
publisher = {Oxford University Press},
abstract = {We thank Dorota Kwiatkowska for critical comments on the manuscript. The work was supported by the research grant BIS6 (2016/22/E/NZ3/00342) from the National Science Centre, Poland. © 2021 Oxford University Press. All rights reserved.},
note = {6},
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pubstate = {published},
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We thank Dorota Kwiatkowska for critical comments on the manuscript. The work was supported by the research grant BIS6 (2016/22/E/NZ3/00342) from the National Science Centre, Poland. © 2021 Oxford University Press. All rights reserved.
Burian, A.
Does Shoot Apical Meristem Function as the Germline in Safeguarding Against Excess of Mutations? Journal Article
In: Frontiers in Plant Science, vol. 12, 2021, (30).
@article{2-s2.0-85113214808,
title = {Does Shoot Apical Meristem Function as the Germline in Safeguarding Against Excess of Mutations?},
author = { A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113214808&doi=10.3389%2ffpls.2021.707740&partnerID=40&md5=186c0d0bf24993559b0adf6c3191cbf8},
doi = {10.3389/fpls.2021.707740},
year = {2021},
date = {2021-01-01},
journal = {Frontiers in Plant Science},
volume = {12},
publisher = {Frontiers Media S.A.},
abstract = {A genetic continuity of living organisms relies on the germline which is a specialized cell lineage producing gametes. Essential in the germline functioning is the protection of genetic information that is subjected to spontaneous mutations. Due to indeterminate growth, late specification of the germline, and unique longevity, plants are expected to accumulate somatic mutations during their lifetime that leads to decrease in individual and population fitness. However, protective mechanisms, similar to those in animals, exist in plant shoot apical meristem (SAM) allowing plants to reduce the accumulation and transmission of mutations. This review describes cellular- and tissue-level mechanisms related to spatio-temporal distribution of cell divisions, organization of stem cell lineages, and cell fate specification to argue that the SAM functions analogous to animal germline. © Copyright © 2021 Burian.},
note = {30},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A genetic continuity of living organisms relies on the germline which is a specialized cell lineage producing gametes. Essential in the germline functioning is the protection of genetic information that is subjected to spontaneous mutations. Due to indeterminate growth, late specification of the germline, and unique longevity, plants are expected to accumulate somatic mutations during their lifetime that leads to decrease in individual and population fitness. However, protective mechanisms, similar to those in animals, exist in plant shoot apical meristem (SAM) allowing plants to reduce the accumulation and transmission of mutations. This review describes cellular- and tissue-level mechanisms related to spatio-temporal distribution of cell divisions, organization of stem cell lineages, and cell fate specification to argue that the SAM functions analogous to animal germline. © Copyright © 2021 Burian.
2019
Kwiatkowska, D.; Natonik-Białoń, S.; Burian, A.
Sequential replicas: Method for in vivo imaging of plant organ surfaces that undergo deformation Journal Article
In: Methods in Molecular Biology, vol. 1992, pp. 239-255, 2019, (0).
@article{2-s2.0-85066800556,
title = {Sequential replicas: Method for in vivo imaging of plant organ surfaces that undergo deformation},
author = { D. Kwiatkowska and S. Natonik-Białoń and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066800556&doi=10.1007%2f978-1-4939-9469-4_16&partnerID=40&md5=47d90005336da94d100820bf77500d68},
doi = {10.1007/978-1-4939-9469-4_16},
year = {2019},
date = {2019-01-01},
journal = {Methods in Molecular Biology},
volume = {1992},
pages = {239-255},
publisher = {Humana Press Inc.},
abstract = {Complex geometry of plant organs and various types of organ surface deformation, including growth or hygroscopic movements, can be analyzed using sequential replica method. It enables obtaining a time-lapse series of high resolution images visualizing details of the examined surface and provides data sufficient for detailed computation of parameters characterizing surface deformation and geometry. Series of molds, made in dental polymer, representing the examined surface are used to obtain casts in epoxy resin or nail polish replicas, which are ready for microscopic examination, while the structure itself remains intact. Images obtained from the epoxy casts in scanning electron microscopy can be further used for 3D reconstruction and computation of local geometry. The sequential replica method is a universal method and can be applied to image complex shapes of a range of structures, like meristems, flowers, leaves, scarious bracts, or trichomes. Different plant species growing in various conditions can be studied. © Springer Science+Business Media, LLC, part of Springer Nature 2019.},
note = {0},
keywords = {},
pubstate = {published},
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}
Complex geometry of plant organs and various types of organ surface deformation, including growth or hygroscopic movements, can be analyzed using sequential replica method. It enables obtaining a time-lapse series of high resolution images visualizing details of the examined surface and provides data sufficient for detailed computation of parameters characterizing surface deformation and geometry. Series of molds, made in dental polymer, representing the examined surface are used to obtain casts in epoxy resin or nail polish replicas, which are ready for microscopic examination, while the structure itself remains intact. Images obtained from the epoxy casts in scanning electron microscopy can be further used for 3D reconstruction and computation of local geometry. The sequential replica method is a universal method and can be applied to image complex shapes of a range of structures, like meristems, flowers, leaves, scarious bracts, or trichomes. Different plant species growing in various conditions can be studied. © Springer Science+Business Media, LLC, part of Springer Nature 2019.
Pałubicki, W.; Kokosza, A.; Burian, A.
Formal description of plant morphogenesis Journal Article
In: Journal of Experimental Botany, vol. 70, no. 14, pp. 3601-3613, 2019, (9).
@article{2-s2.0-85070485199,
title = {Formal description of plant morphogenesis},
author = { W. Pałubicki and A. Kokosza and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070485199&doi=10.1093%2fjxb%2ferz210&partnerID=40&md5=77fa14f80fd7fa38c03946f5367419f7},
doi = {10.1093/jxb/erz210},
year = {2019},
date = {2019-01-01},
journal = {Journal of Experimental Botany},
volume = {70},
number = {14},
pages = {3601-3613},
publisher = {Oxford University Press},
abstract = {Plant morphogenesis may be characterized by complex feedback mechanisms between signals specifying growth and by the growth of the plant body itself. Comprehension of such feedback mechanisms is an ongoing research task and can be aided with formal descriptions of morphogenesis. In this review, we present a number of established mathematical paradigms that are useful to the formal representation of plant shape, and of biomechanical and biochemical signaling. Specifically, we discuss work from a range of research areas including plant biology, material sciences, fluid dynamics, and computer graphics. Treating plants as organized systems of information processing allows us to compare these different mathematical methods in terms of their expressive power of biological hypotheses. This is an attempt to bring together a large number of computational modeling concepts and make them accessible to the analytical as well as empirical student of plant morphogenesis. © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.},
note = {9},
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pubstate = {published},
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Plant morphogenesis may be characterized by complex feedback mechanisms between signals specifying growth and by the growth of the plant body itself. Comprehension of such feedback mechanisms is an ongoing research task and can be aided with formal descriptions of morphogenesis. In this review, we present a number of established mathematical paradigms that are useful to the formal representation of plant shape, and of biomechanical and biochemical signaling. Specifically, we discuss work from a range of research areas including plant biology, material sciences, fluid dynamics, and computer graphics. Treating plants as organized systems of information processing allows us to compare these different mathematical methods in terms of their expressive power of biological hypotheses. This is an attempt to bring together a large number of computational modeling concepts and make them accessible to the analytical as well as empirical student of plant morphogenesis. © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.
Hamant, O.; Das, P.; Burian, A.
Time-lapse imaging of developing shoot meristems using a confocal laser scanning microscope Journal Article
In: Methods in Molecular Biology, vol. 1992, pp. 257-268, 2019, (17).
@article{2-s2.0-85066787945,
title = {Time-lapse imaging of developing shoot meristems using a confocal laser scanning microscope},
author = { O. Hamant and P. Das and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066787945&doi=10.1007%2f978-1-4939-9469-4_17&partnerID=40&md5=bfe82e98ddc3063d9cab14eec181660b},
doi = {10.1007/978-1-4939-9469-4_17},
year = {2019},
date = {2019-01-01},
journal = {Methods in Molecular Biology},
volume = {1992},
pages = {257-268},
publisher = {Humana Press Inc.},
abstract = {Analysis of meristem shape and gene expression pattern has been conducted in many species over the past decades. Recent live imaging techniques have allowed for an unprecedented accumulation of data on the biology of meristematic cells, as well as a better understanding of the molecular and biophysical mechanisms behind shape changes in this tissue. Here we describe in detail how to prepare shoot apices of both Arabidopsis and tomato, in order to image them over time using a confocal microscope equipped with a long distance water-dipping lens. © Springer Science+Business Media, LLC, part of Springer Nature 2019.},
note = {17},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Analysis of meristem shape and gene expression pattern has been conducted in many species over the past decades. Recent live imaging techniques have allowed for an unprecedented accumulation of data on the biology of meristematic cells, as well as a better understanding of the molecular and biophysical mechanisms behind shape changes in this tissue. Here we describe in detail how to prepare shoot apices of both Arabidopsis and tomato, in order to image them over time using a confocal microscope equipped with a long distance water-dipping lens. © Springer Science+Business Media, LLC, part of Springer Nature 2019.
Echevin, E.; Gloanec, C. Le; Skowrońska, N.; Routier-Kierzkowska, A. L.; Burian, A.; Kierzkowski, D.
Growth and biomechanics of shoot organs Journal Article
In: Journal of Experimental Botany, vol. 70, no. 14, pp. 3573-3585, 2019, (32).
@article{2-s2.0-85070422346,
title = {Growth and biomechanics of shoot organs},
author = { E. Echevin and C. Le Gloanec and N. Skowrońska and A.L. Routier-Kierzkowska and A. Burian and D. Kierzkowski},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070422346&doi=10.1093%2fjxb%2ferz205&partnerID=40&md5=82e0c72d955a746b2149a934160e39ec},
doi = {10.1093/jxb/erz205},
year = {2019},
date = {2019-01-01},
journal = {Journal of Experimental Botany},
volume = {70},
number = {14},
pages = {3573-3585},
publisher = {Oxford University Press},
abstract = {Plant organs arise through complex interactions between biological and physical factors that control morphogenesis. While there has been tremendous progress in the understanding of the genetics behind development, we know much less about how mechanical forces control growth in plants. In recent years, new multidisciplinary research combining genetics, live-imaging, physics, and computational modeling has begun to fill this gap by revealing the crucial role of biomechanics in the establishment of plant organs. In this review, we provide an overview of our current understanding of growth during initiation, patterning, and expansion of shoot lateral organs. We discuss how growth is controlled by physical forces, and how mechanical stresses generated during growth can control morphogenesis at the level of both cells and tissues. Understanding the mechanical basis of growth and morphogenesis in plants is in its early days, and many puzzling facts are yet to be deciphered. © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.},
note = {32},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Plant organs arise through complex interactions between biological and physical factors that control morphogenesis. While there has been tremendous progress in the understanding of the genetics behind development, we know much less about how mechanical forces control growth in plants. In recent years, new multidisciplinary research combining genetics, live-imaging, physics, and computational modeling has begun to fill this gap by revealing the crucial role of biomechanics in the establishment of plant organs. In this review, we provide an overview of our current understanding of growth during initiation, patterning, and expansion of shoot lateral organs. We discuss how growth is controlled by physical forces, and how mechanical stresses generated during growth can control morphogenesis at the level of both cells and tissues. Understanding the mechanical basis of growth and morphogenesis in plants is in its early days, and many puzzling facts are yet to be deciphered. © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.
2016
Burian, A.; Barbier de Reuille, P.; Kuhlemeier, C.
Patterns of Stem Cell Divisions Contribute to Plant Longevity Journal Article
In: Current Biology, vol. 26, no. 11, pp. 1385-1394, 2016, (127).
@article{2-s2.0-84964940338,
title = {Patterns of Stem Cell Divisions Contribute to Plant Longevity},
author = { A. Burian and P. Barbier de Reuille and C. Kuhlemeier},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964940338&doi=10.1016%2fj.cub.2016.03.067&partnerID=40&md5=2fdd5dba375f23935ad4901d92079d44},
doi = {10.1016/j.cub.2016.03.067},
year = {2016},
date = {2016-01-01},
journal = {Current Biology},
volume = {26},
number = {11},
pages = {1385-1394},
publisher = {Cell Press},
abstract = {The lifespan of plants ranges from a few weeks in annuals to thousands of years in trees. It is hard to explain such extreme longevity considering that DNA replication errors inevitably cause mutations. Without purging through meiotic recombination, the accumulation of somatic mutations will eventually result in mutational meltdown, a phenomenon known as Muller's ratchet. Nevertheless, the lifespan of trees is limited more often by incidental disease or structural damage than by genetic aging. The key determinants of tree architecture are the axillary meristems, which form in the axils of leaves and grow out to form branches. The number of branches is low in annual plants, but in perennial plants iterative branching can result in thousands of terminal branches. Here, we use stem cell ablation and quantitative cell-lineage analysis to show that axillary meristems are set aside early, analogous to the metazoan germline. While neighboring cells divide vigorously, axillary meristem precursors maintain a quiescent state, with only 7–9 cell divisions occurring between the apical and axillary meristem. During iterative branching, the number of branches increases exponentially, while the number of cell divisions increases linearly. Moreover, computational modeling shows that stem cell arrangement and positioning of axillary meristems distribute somatic mutations around the main shoot, preventing their fixation and maximizing genetic heterogeneity. These features slow down Muller's ratchet and thereby extend lifespan. © 2016 Elsevier Ltd},
note = {127},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The lifespan of plants ranges from a few weeks in annuals to thousands of years in trees. It is hard to explain such extreme longevity considering that DNA replication errors inevitably cause mutations. Without purging through meiotic recombination, the accumulation of somatic mutations will eventually result in mutational meltdown, a phenomenon known as Muller's ratchet. Nevertheless, the lifespan of trees is limited more often by incidental disease or structural damage than by genetic aging. The key determinants of tree architecture are the axillary meristems, which form in the axils of leaves and grow out to form branches. The number of branches is low in annual plants, but in perennial plants iterative branching can result in thousands of terminal branches. Here, we use stem cell ablation and quantitative cell-lineage analysis to show that axillary meristems are set aside early, analogous to the metazoan germline. While neighboring cells divide vigorously, axillary meristem precursors maintain a quiescent state, with only 7–9 cell divisions occurring between the apical and axillary meristem. During iterative branching, the number of branches increases exponentially, while the number of cell divisions increases linearly. Moreover, computational modeling shows that stem cell arrangement and positioning of axillary meristems distribute somatic mutations around the main shoot, preventing their fixation and maximizing genetic heterogeneity. These features slow down Muller's ratchet and thereby extend lifespan. © 2016 Elsevier Ltd
2015
Burian, A.; Raczyńska-Szajgin, M.; Borowska-Wykręt, D.; Piatek, A.; Aida, M.; Kwiatkowska, D.
The CUP-SHAPED COTYLEDON2 and 3 genes have a post-meristematic effect on Arabidopsis thaliana phyllotaxis Journal Article
In: Annals of Botany, vol. 115, no. 5, pp. 807-820, 2015, (18).
@article{2-s2.0-84927145226,
title = {The CUP-SHAPED COTYLEDON2 and 3 genes have a post-meristematic effect on Arabidopsis thaliana phyllotaxis},
author = { A. Burian and M. Raczyńska-Szajgin and D. Borowska-Wykręt and A. Piatek and M. Aida and D. Kwiatkowska},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927145226&doi=10.1093%2faob%2fmcv013&partnerID=40&md5=1c4e3943f718abdd6aed21ddfe1422a9},
doi = {10.1093/aob/mcv013},
year = {2015},
date = {2015-01-01},
journal = {Annals of Botany},
volume = {115},
number = {5},
pages = {807-820},
publisher = {Oxford University Press},
abstract = {Background and Aims: The arrangement of flowers in inflorescence shoots of Arabidopsis thaliana represents a regular spiral Fibonacci phyllotaxis. However, in the cuc2 cuc3 double mutant, flower pedicels are fused to the inflorescence stem, and phyllotaxis is aberrant in the mature shoot regions. This study examined the causes of this altered development, and in particular whether the mutant phenotype is a consequence of defects at the shoot apex, or whether post-meristematic events are involved. Methods: The distribution of flower pedicels and vascular traces was examined in cross-sections of mature shoots; sequential replicas were used to investigate the phyllotaxis and geometry of shoot apices, and growth of the young stem surface. The expression pattern of CUC3 was analysed by examining its promoter activity. Key Results: Phyllotaxis irregularity in the cuc2 cuc3 double mutant arises during the post-meristematic phase of shoot development. In particular, growth and cell divisions in nodes of the elongating stem are not restricted in the mutant, resulting in pedicel-stem fusion. On the other hand, phyllotaxis in the mutant shoot apex is nearly as regular as that of the wild type. Vascular phyllotaxis, generated almost simultaneously with the phyllotaxis at the apex, is also much more regular than pedicel phyllotaxis. The most apparent phenotype of the mutant apices is a higher number of contact parastichies. This phenotype is associated with increased meristem size, decreased angular width of primordia and a shorter plastochron. In addition, the appearance of a sharp and deep crease, a characteristic shape of the adaxial primordium boundary, is slightly delayed and reduced in the mutant shoot apices. Conclusions: The cuc2 cuc3 double mutant displays irregular phyllotaxis in the mature shoot but not in the shoot apex, thus showing a post-meristematic effect of the mutations on phyllotaxis. The main cause of this effect is the formation of pedicel-stem fusions, leading to an alteration of the axial positioning of flowers. Phyllotaxis based on the position of vascular flower traces suggests an additional mechanism of post-meristematic phyllotaxis alteration. Higher density of flower primordia may be involved in the post-meristematic effect on phyllotaxis, whereas delayed crease formation may be involved in the fusion phenotype. Promoter activity of CUC3 is consistent with its post-meristematic role in phyllotaxis. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.},
note = {18},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background and Aims: The arrangement of flowers in inflorescence shoots of Arabidopsis thaliana represents a regular spiral Fibonacci phyllotaxis. However, in the cuc2 cuc3 double mutant, flower pedicels are fused to the inflorescence stem, and phyllotaxis is aberrant in the mature shoot regions. This study examined the causes of this altered development, and in particular whether the mutant phenotype is a consequence of defects at the shoot apex, or whether post-meristematic events are involved. Methods: The distribution of flower pedicels and vascular traces was examined in cross-sections of mature shoots; sequential replicas were used to investigate the phyllotaxis and geometry of shoot apices, and growth of the young stem surface. The expression pattern of CUC3 was analysed by examining its promoter activity. Key Results: Phyllotaxis irregularity in the cuc2 cuc3 double mutant arises during the post-meristematic phase of shoot development. In particular, growth and cell divisions in nodes of the elongating stem are not restricted in the mutant, resulting in pedicel-stem fusion. On the other hand, phyllotaxis in the mutant shoot apex is nearly as regular as that of the wild type. Vascular phyllotaxis, generated almost simultaneously with the phyllotaxis at the apex, is also much more regular than pedicel phyllotaxis. The most apparent phenotype of the mutant apices is a higher number of contact parastichies. This phenotype is associated with increased meristem size, decreased angular width of primordia and a shorter plastochron. In addition, the appearance of a sharp and deep crease, a characteristic shape of the adaxial primordium boundary, is slightly delayed and reduced in the mutant shoot apices. Conclusions: The cuc2 cuc3 double mutant displays irregular phyllotaxis in the mature shoot but not in the shoot apex, thus showing a post-meristematic effect of the mutations on phyllotaxis. The main cause of this effect is the formation of pedicel-stem fusions, leading to an alteration of the axial positioning of flowers. Phyllotaxis based on the position of vascular flower traces suggests an additional mechanism of post-meristematic phyllotaxis alteration. Higher density of flower primordia may be involved in the post-meristematic effect on phyllotaxis, whereas delayed crease formation may be involved in the fusion phenotype. Promoter activity of CUC3 is consistent with its post-meristematic role in phyllotaxis. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
de Reuille, P. B.; Routier-Kierzkowska, A. L.; Kierzkowski, D.; Bassel, G. W.; Schüpbach, T.; Tauriello, G.; Bajpai, N.; Strauss, S.; Weber, A.; Kiss, A.; Burian, A.; Hofhuis, H.; Sapala, A.; Lipowczan, M.; Heimlicher, M. B.; Robinson, S.; Bayer, E. M.; Basler, K.; Koumoutsakos, P.; Roeder, A. H. K.; Aegerter-Wilmsen, T.; Nakayama, N.; Tsiantis, M.; Hay, A.; Kwiatkowska, D.; Xenarios, I.; Kuhlemeier, C.; Smith, R. S.
MorphoGraphX: A platform for quantifying morphogenesis in 4D Journal Article
In: eLife, vol. 4, no. MAY, pp. 1-20, 2015, (389).
@article{2-s2.0-84930640355,
title = {MorphoGraphX: A platform for quantifying morphogenesis in 4D},
author = { P.B. de Reuille and A.L. Routier-Kierzkowska and D. Kierzkowski and G.W. Bassel and T. Schüpbach and G. Tauriello and N. Bajpai and S. Strauss and A. Weber and A. Kiss and A. Burian and H. Hofhuis and A. Sapala and M. Lipowczan and M.B. Heimlicher and S. Robinson and E.M. Bayer and K. Basler and P. Koumoutsakos and A.H.K. Roeder and T. Aegerter-Wilmsen and N. Nakayama and M. Tsiantis and A. Hay and D. Kwiatkowska and I. Xenarios and C. Kuhlemeier and R.S. Smith},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930640355&doi=10.7554%2feLife.05864&partnerID=40&md5=2bc848f64b00656937202a22152fb707},
doi = {10.7554/eLife.05864},
year = {2015},
date = {2015-01-01},
journal = {eLife},
volume = {4},
number = {MAY},
pages = {1-20},
publisher = {eLife Sciences Publications Ltd},
abstract = {Morphogenesis emerges from complex multiscale interactions between genetic and mechanical processes. To understand these processes, the evolution of cell shape, proliferation and gene expression must be quantified. This quantification is usually performed either in full 3D, which is computationally expensive and technically challenging, or on 2D planar projections, which introduces geometrical artifacts on highly curved organs. Here we present MorphoGraphX (www.MorphoGraphX.org), a software that bridges this gap by working directly with curved surface images extracted from 3D data. In addition to traditional 3D image analysis, we have developed algorithms to operate on curved surfaces, such as cell segmentation, lineage tracking and fluorescence signal quantification. The software’s modular design makes it easy to include existing libraries, or to implement new algorithms. Cell geometries extracted with MorphoGraphX can be exported and used as templates for simulation models, providing a powerful platform to investigate the interactions between shape, genes and growth. © Barbier de Reuille et al.},
note = {389},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Morphogenesis emerges from complex multiscale interactions between genetic and mechanical processes. To understand these processes, the evolution of cell shape, proliferation and gene expression must be quantified. This quantification is usually performed either in full 3D, which is computationally expensive and technically challenging, or on 2D planar projections, which introduces geometrical artifacts on highly curved organs. Here we present MorphoGraphX (www.MorphoGraphX.org), a software that bridges this gap by working directly with curved surface images extracted from 3D data. In addition to traditional 3D image analysis, we have developed algorithms to operate on curved surfaces, such as cell segmentation, lineage tracking and fluorescence signal quantification. The software’s modular design makes it easy to include existing libraries, or to implement new algorithms. Cell geometries extracted with MorphoGraphX can be exported and used as templates for simulation models, providing a powerful platform to investigate the interactions between shape, genes and growth. © Barbier de Reuille et al.
Jöst, M.; Esfeld, K.; Burian, A.; Cannarozzi, G.; Chanyalew, S.; Kuhlemeier, C.; Assefa, K.; Tadele, Z.
Semi-dwarfism and lodging tolerance in tef (Eragrostis tef) is linked to a mutation in the α-Tubulin 1 gene Journal Article
In: Journal of Experimental Botany, vol. 66, no. 3, pp. 933-944, 2015, (42).
@article{2-s2.0-84940688839,
title = {Semi-dwarfism and lodging tolerance in tef (Eragrostis tef) is linked to a mutation in the α-Tubulin 1 gene},
author = { M. Jöst and K. Esfeld and A. Burian and G. Cannarozzi and S. Chanyalew and C. Kuhlemeier and K. Assefa and Z. Tadele},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940688839&doi=10.1093%2fjxb%2feru452&partnerID=40&md5=4dc65f654d13eb821c5bc758a678ce7d},
doi = {10.1093/jxb/eru452},
year = {2015},
date = {2015-01-01},
journal = {Journal of Experimental Botany},
volume = {66},
number = {3},
pages = {933-944},
publisher = {Oxford University Press},
abstract = {Genetic improvement of native crops is a new and promising strategy to combat hunger in the developing world. Tef is the major staple food crop for approximately 50 million people in Ethiopia. As an indigenous cereal, it is well adapted to diverse climatic and soil conditions; however, its productivity is extremely low mainly due to susceptibility to lodging. Tef has a tall and weak stem, liable to lodge (or fall over), which is aggravated by wind, rain, or application of nitrogen fertilizer. To circumvent this problem, the first semi-dwarf lodging-tolerant tef line, called kegne, was developed from an ethyl methanesulphonate (EMS)-mutagenized population. The response of kegne to microtubule-depolymerizing and -stabilizing drugs, as well as subsequent gene sequencing and segregation analysis, suggests that a defect in the α-Tubulin gene is functionally and genetically tightly linked to the kegne phenotype. In diploid species such as rice, homozygous mutations in α-Tubulin genes result in extreme dwarfism and weak stems. In the allotetraploid tef, only one homeologue is mutated, and the presence of the second intact α-Tubulin gene copy confers the agriculturally beneficial semi-dwarf and lodging-tolerant phenotype. Introgression of kegne into locally adapted and popular tef cultivars in Ethiopia will increase the lodging tolerance in the tef germplasm and, as a result, will improve the productivity of this valuable crop. © The Author 2014.},
note = {42},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Genetic improvement of native crops is a new and promising strategy to combat hunger in the developing world. Tef is the major staple food crop for approximately 50 million people in Ethiopia. As an indigenous cereal, it is well adapted to diverse climatic and soil conditions; however, its productivity is extremely low mainly due to susceptibility to lodging. Tef has a tall and weak stem, liable to lodge (or fall over), which is aggravated by wind, rain, or application of nitrogen fertilizer. To circumvent this problem, the first semi-dwarf lodging-tolerant tef line, called kegne, was developed from an ethyl methanesulphonate (EMS)-mutagenized population. The response of kegne to microtubule-depolymerizing and -stabilizing drugs, as well as subsequent gene sequencing and segregation analysis, suggests that a defect in the α-Tubulin gene is functionally and genetically tightly linked to the kegne phenotype. In diploid species such as rice, homozygous mutations in α-Tubulin genes result in extreme dwarfism and weak stems. In the allotetraploid tef, only one homeologue is mutated, and the presence of the second intact α-Tubulin gene copy confers the agriculturally beneficial semi-dwarf and lodging-tolerant phenotype. Introgression of kegne into locally adapted and popular tef cultivars in Ethiopia will increase the lodging tolerance in the tef germplasm and, as a result, will improve the productivity of this valuable crop. © The Author 2014.
2014
Boudaoud, A.; Burian, A.; Borowska-Wykręt, D.; Uyttewaal, M.; Wrzalik, R.; Kwiatkowska, D.; Hamant, O.
FibrilTool, an ImageJ plug-in to quantify fibrillar structures in raw microscopy images Journal Article
In: Nature Protocols, vol. 9, no. 2, pp. 457-463, 2014, (467).
@article{2-s2.0-84893302816,
title = {FibrilTool, an ImageJ plug-in to quantify fibrillar structures in raw microscopy images},
author = { A. Boudaoud and A. Burian and D. Borowska-Wykręt and M. Uyttewaal and R. Wrzalik and D. Kwiatkowska and O. Hamant},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893302816&doi=10.1038%2fnprot.2014.024&partnerID=40&md5=31d61c13cf41d7b9c2edf3ac85598e3e},
doi = {10.1038/nprot.2014.024},
year = {2014},
date = {2014-01-01},
journal = {Nature Protocols},
volume = {9},
number = {2},
pages = {457-463},
publisher = {Nature Publishing Group},
abstract = {Cell biology heavily relies on the behavior of fibrillar structures, such as the cytoskeleton, yet the analysis of their behavior in tissues often remains qualitative. Image analysis tools have been developed to quantify this behavior, but they often involve an image pre-processing stage that may bias the output and/or they require specific software. Here we describe FibrilTool, an ImageJ plug-in based on the concept of nematic tensor, which can provide a quantitative description of the anisotropy of fiber arrays and their average orientation in cells, directly from raw images obtained by any form of microscopy. FibrilTool has been validated on microtubules, actin and cellulose microfibrils, but it may also help analyze other fibrillar structures, such as collagen, or the texture of various materials. The tool is ImageJ-based, and it is therefore freely accessible to the scientific community and does not require specific computational setup. The tool provides the average orientation and anisotropy of fiber arrays in a given region of interest (ROI) in a few seconds. © 2014 Nature America, Inc. All rights reserved.},
note = {467},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cell biology heavily relies on the behavior of fibrillar structures, such as the cytoskeleton, yet the analysis of their behavior in tissues often remains qualitative. Image analysis tools have been developed to quantify this behavior, but they often involve an image pre-processing stage that may bias the output and/or they require specific software. Here we describe FibrilTool, an ImageJ plug-in based on the concept of nematic tensor, which can provide a quantitative description of the anisotropy of fiber arrays and their average orientation in cells, directly from raw images obtained by any form of microscopy. FibrilTool has been validated on microtubules, actin and cellulose microfibrils, but it may also help analyze other fibrillar structures, such as collagen, or the texture of various materials. The tool is ImageJ-based, and it is therefore freely accessible to the scientific community and does not require specific computational setup. The tool provides the average orientation and anisotropy of fiber arrays in a given region of interest (ROI) in a few seconds. © 2014 Nature America, Inc. All rights reserved.
Hamant, O.; Das, P.; Burian, A.
Time-lapse imaging of developing meristems using confocal laser scanning microscope Journal Article
In: Methods in Molecular Biology, vol. 1080, pp. 111-119, 2014, (21).
@article{2-s2.0-84934440904,
title = {Time-lapse imaging of developing meristems using confocal laser scanning microscope},
author = { O. Hamant and P. Das and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934440904&doi=10.1007%2f978-1-62703-643-6_9&partnerID=40&md5=348808882c0388ab2e1b5fe4bae5e69f},
doi = {10.1007/978-1-62703-643-6_9},
year = {2014},
date = {2014-01-01},
journal = {Methods in Molecular Biology},
volume = {1080},
pages = {111-119},
publisher = {Humana Press Inc.},
abstract = {Analysis of shoot meristem shape and gene expression pattern has been conducted in many species over the past decades. Recent live imaging techniques have allowed an unprecedented accumulation of data on the biology of meristematic cells, as well as a better understanding of the molecular and biophysical mechanisms behind shape changes in this tissue. Here we describe in detail how to prepare shoot apices of both Arabidopsis and tomato, in order to image them over time using a confocal microscope equipped with a long-distance water-dipping lens. © 2014 Springer Science+Business Media, New York.},
note = {21},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Analysis of shoot meristem shape and gene expression pattern has been conducted in many species over the past decades. Recent live imaging techniques have allowed an unprecedented accumulation of data on the biology of meristematic cells, as well as a better understanding of the molecular and biophysical mechanisms behind shape changes in this tissue. Here we describe in detail how to prepare shoot apices of both Arabidopsis and tomato, in order to image them over time using a confocal microscope equipped with a long-distance water-dipping lens. © 2014 Springer Science+Business Media, New York.
Kwiatkowska, D.; Burian, A.
Sequential replicas for in Vivo imaging of growing organ surfaces Journal Article
In: Methods in Molecular Biology, vol. 1080, pp. 99-110, 2014, (6).
@article{2-s2.0-84934439158,
title = {Sequential replicas for in Vivo imaging of growing organ surfaces},
author = { D. Kwiatkowska and A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934439158&doi=10.1007%2f978-1-62703-643-6_8&partnerID=40&md5=5e8a4b9e21d32d4b2da8cb034bc32651},
doi = {10.1007/978-1-62703-643-6_8},
year = {2014},
date = {2014-01-01},
journal = {Methods in Molecular Biology},
volume = {1080},
pages = {99-110},
publisher = {Humana Press Inc.},
abstract = {Sequential replica method facilitates in vivo imaging of plant surface and provides data sufficient for detailed computation of geometry and growth. It enables obtaining a series of high-resolution images visualizing details of the examined surface. Series of molds, made in dental polymer, representing the examined surface are used to obtain casts in epoxy resin, which are in turn observed by scanning electron microscopy, while the structure itself remains intact. Images obtained from casts can be further used for data extraction, comprising 3D reconstruction and computation of local geometry and cell growth parameters. The sequential replica method is a universal method and can be applied to image complex shapes of a range of structures, like meristems, flowers, stems, leaves, or various types of trichomes. Different plant species growing in various conditions can be studied. © 2014 Springer Science+Business Media, New York.},
note = {6},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sequential replica method facilitates in vivo imaging of plant surface and provides data sufficient for detailed computation of geometry and growth. It enables obtaining a series of high-resolution images visualizing details of the examined surface. Series of molds, made in dental polymer, representing the examined surface are used to obtain casts in epoxy resin, which are in turn observed by scanning electron microscopy, while the structure itself remains intact. Images obtained from casts can be further used for data extraction, comprising 3D reconstruction and computation of local geometry and cell growth parameters. The sequential replica method is a universal method and can be applied to image complex shapes of a range of structures, like meristems, flowers, stems, leaves, or various types of trichomes. Different plant species growing in various conditions can be studied. © 2014 Springer Science+Business Media, New York.
2013
Burian, A.; Ludynia, M.; Uyttewaal, M.; Traas, J.; Boudaoud, A.; Hamant, O.; Kwiatkowska, D.
A correlative microscopy approach relates microtubule behaviour, local organ geometry, and cell growth at the Arabidopsis shoot apical meristem Journal Article
In: Journal of Experimental Botany, vol. 64, no. 18, pp. 5753-5767, 2013, (42).
@article{2-s2.0-84891507470,
title = {A correlative microscopy approach relates microtubule behaviour, local organ geometry, and cell growth at the Arabidopsis shoot apical meristem},
author = { A. Burian and M. Ludynia and M. Uyttewaal and J. Traas and A. Boudaoud and O. Hamant and D. Kwiatkowska},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891507470&doi=10.1093%2fjxb%2fert352&partnerID=40&md5=6c5bf7791016042f4e33afccbf0e69d1},
doi = {10.1093/jxb/ert352},
year = {2013},
date = {2013-01-01},
journal = {Journal of Experimental Botany},
volume = {64},
number = {18},
pages = {5753-5767},
abstract = {Cortical microtubules (CMTs) are often aligned in a particular direction in individual cells or even in groups of cells and play a central role in the definition of growth anisotropy. How the CMTs themselves are aligned is not well known, but two hypotheses have been proposed. According to the first hypothesis, CMTs align perpendicular to the maximal growth direction, and, according to the second, CMTs align parallel to the maximal stress direction. Since both hypotheses were formulated on the basis of mainly qualitative assessments, the link between CMT organization, organ geometry, and cell growth is revisited using a quantitative approach. For this purpose, CMT orientation, local curvature, and growth parameters for each cell were measured in the growing shoot apical meristem (SAM) of Arabidopsis thaliana. Using this approach, it has been shown that stable CMTs tend to be perpendicular to the direction of maximal growth in cells at the SAM periphery, but parallel in the cells at the boundary domain. When examining the local curvature of the SAM surface, no strict correlation between curvature and CMT arrangement was found, which implies that SAM geometry, and presumed geometry-derived stress distribution, is not sufficient to prescribe the CMT orientation. However, a better match between stress and CMTs was found when mechanical stress derived from differential growth was also considered. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology.},
note = {42},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cortical microtubules (CMTs) are often aligned in a particular direction in individual cells or even in groups of cells and play a central role in the definition of growth anisotropy. How the CMTs themselves are aligned is not well known, but two hypotheses have been proposed. According to the first hypothesis, CMTs align perpendicular to the maximal growth direction, and, according to the second, CMTs align parallel to the maximal stress direction. Since both hypotheses were formulated on the basis of mainly qualitative assessments, the link between CMT organization, organ geometry, and cell growth is revisited using a quantitative approach. For this purpose, CMT orientation, local curvature, and growth parameters for each cell were measured in the growing shoot apical meristem (SAM) of Arabidopsis thaliana. Using this approach, it has been shown that stable CMTs tend to be perpendicular to the direction of maximal growth in cells at the SAM periphery, but parallel in the cells at the boundary domain. When examining the local curvature of the SAM surface, no strict correlation between curvature and CMT arrangement was found, which implies that SAM geometry, and presumed geometry-derived stress distribution, is not sufficient to prescribe the CMT orientation. However, a better match between stress and CMTs was found when mechanical stress derived from differential growth was also considered. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology.
Robinson, S.; Burian, A.; Couturier, E.; Landrein, B.; Louveaux, M.; Neumann, E. D.; Peaucelle, A.; Weber, A.; Nakayama, N.
Mechanical control of morphogenesis at the shoot apex Journal Article
In: Journal of Experimental Botany, vol. 64, no. 15, pp. 4729-4744, 2013, (52).
@article{2-s2.0-84887856036,
title = {Mechanical control of morphogenesis at the shoot apex},
author = { S. Robinson and A. Burian and E. Couturier and B. Landrein and M. Louveaux and E.D. Neumann and A. Peaucelle and A. Weber and N. Nakayama},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887856036&doi=10.1093%2fjxb%2fert199&partnerID=40&md5=7bfbca44aa98a8926aad22f03eb25dcd},
doi = {10.1093/jxb/ert199},
year = {2013},
date = {2013-01-01},
journal = {Journal of Experimental Botany},
volume = {64},
number = {15},
pages = {4729-4744},
abstract = {Morphogenesis does not just require the correct expression of patterning genes; these genes must induce the precise mechanical changes necessary to produce a new form. Mechanical characterization of plant growth is not new; however, in recent years, new technologies and interdisciplinary collaborations have made it feasible in young tissues such as the shoot apex. Analysis of tissues where active growth and developmental patterning are taking place has revealed biologically significant variability in mechanical properties and has even suggested that mechanical changes in the tissue can feed back to direct morphogenesis. Here, an overview is given of the current understanding of the mechanical dynamics and its influence on cellular and developmental processes in the shoot apex. We are only starting to uncover the mechanical basis of morphogenesis, and many exciting questions remain to be answered. © The Author 2013.},
note = {52},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Morphogenesis does not just require the correct expression of patterning genes; these genes must induce the precise mechanical changes necessary to produce a new form. Mechanical characterization of plant growth is not new; however, in recent years, new technologies and interdisciplinary collaborations have made it feasible in young tissues such as the shoot apex. Analysis of tissues where active growth and developmental patterning are taking place has revealed biologically significant variability in mechanical properties and has even suggested that mechanical changes in the tissue can feed back to direct morphogenesis. Here, an overview is given of the current understanding of the mechanical dynamics and its influence on cellular and developmental processes in the shoot apex. We are only starting to uncover the mechanical basis of morphogenesis, and many exciting questions remain to be answered. © The Author 2013.
2012
Uyttewaal, M.; Burian, A.; Alim, K.; Landrein, B.; Borowska-Wykręt, D.; Dedieu, A.; Peaucelle, A.; Ludynia, M.; Traas, J.; Boudaoud, A.; Kwiatkowska, D.; Hamant, O.
Mechanical stress acts via Katanin to amplify differences in growth rate between adjacent cells in Arabidopsis Journal Article
In: Cell, vol. 149, no. 2, pp. 439-451, 2012, (370).
@article{2-s2.0-84859771647,
title = {Mechanical stress acts via Katanin to amplify differences in growth rate between adjacent cells in Arabidopsis},
author = { M. Uyttewaal and A. Burian and K. Alim and B. Landrein and D. Borowska-Wykręt and A. Dedieu and A. Peaucelle and M. Ludynia and J. Traas and A. Boudaoud and D. Kwiatkowska and O. Hamant},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859771647&doi=10.1016%2fj.cell.2012.02.048&partnerID=40&md5=24eb759f7d676173e05b18fa44f42459},
doi = {10.1016/j.cell.2012.02.048},
year = {2012},
date = {2012-01-01},
journal = {Cell},
volume = {149},
number = {2},
pages = {439-451},
publisher = {Elsevier B.V.},
abstract = {The presence of diffuse morphogen gradients in tissues supports a view in which growth is locally homogenous. Here we challenge this view: we used a high-resolution quantitative approach to reveal significant growth variability among neighboring cells in the shoot apical meristem, the plant stem cell niche. This variability was strongly decreased in a mutant impaired in the microtubule-severing protein katanin. Major shape defects in the mutant could be related to a local decrease in growth heterogeneity. We show that katanin is required for the cell's competence to respond to the mechanical forces generated by growth. This provides the basis for a model in which microtubule dynamics allow the cell to respond efficiently to mechanical forces. This in turn can amplify local growth-rate gradients, yielding more heterogeneous growth and supporting morphogenesis. © 2012 Elsevier Inc.},
note = {370},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The presence of diffuse morphogen gradients in tissues supports a view in which growth is locally homogenous. Here we challenge this view: we used a high-resolution quantitative approach to reveal significant growth variability among neighboring cells in the shoot apical meristem, the plant stem cell niche. This variability was strongly decreased in a mutant impaired in the microtubule-severing protein katanin. Major shape defects in the mutant could be related to a local decrease in growth heterogeneity. We show that katanin is required for the cell's competence to respond to the mechanical forces generated by growth. This provides the basis for a model in which microtubule dynamics allow the cell to respond efficiently to mechanical forces. This in turn can amplify local growth-rate gradients, yielding more heterogeneous growth and supporting morphogenesis. © 2012 Elsevier Inc.
2011
Burian, A.; Hejnowicz, Z.
Fusicoccin affects cortical microtubule orientation in the isolated epidermis of sunflower hypocotyls Journal Article
In: Plant Biology, vol. 13, no. 1, pp. 201-208, 2011, (5).
@article{2-s2.0-78650154748,
title = {Fusicoccin affects cortical microtubule orientation in the isolated epidermis of sunflower hypocotyls},
author = { A. Burian and Z. Hejnowicz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650154748&doi=10.1111%2fj.1438-8677.2010.00339.x&partnerID=40&md5=df7f3157b7f825a9fb3ecdb02b3ddb84},
doi = {10.1111/j.1438-8677.2010.00339.x},
year = {2011},
date = {2011-01-01},
journal = {Plant Biology},
volume = {13},
number = {1},
pages = {201-208},
abstract = {Epidermal peels isolated from sunflower hypocotyls provide a convenient model to study the relationship between cortical microtubule orientation and strain rate. Extension of peels can be modulated using chemical treatment and mechanical stress, i.e., by adding a chemical to the incubation medium and applying a load exceeding the yield threshold for irreversible (plastic) strain. In this study, peels were pre-incubated for ca. 12 h (long-term pre-incubation) or for 1 h (short-term pre-incubation). In the long-term pre-incubated peels, fusicoccin applied to the medium neither enhanced the rate of longitudinal plastic strain of loaded peels, nor affected microtubule orientation. However, fusicoccin increased the strain rate of short-term, pre-incubated peels and affected microtubule orientation in both extending (loaded) and non-extending (unloaded) peels. Without fusicoccin, microtubule orientation was generally longitudinal or steep, whereas in fusicoccin-treated unloaded peels it was transverse and oblique microtubules in peel portions corresponding to the apical part of the hypocotyl. Although the frequency of transverse orientation was increased through loading, there was no strong correlation between the rate of fusicoccin-induced strain and microtubule orientation. It is hypothesized that the insensitivity of long-term pre-incubated peels to fusicoccin with respect to strain rate is due to a lack of active plasma membrane H+-ATPases. Thus, the sensitivity of short-term, pre-incubated, unloaded (non-extending) peels to fusicoccin, with respect to microtubule orientation, indicates that orientation might be affected by electric currents resulting from fusicoccin stimulation of H+-ATPases. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.},
note = {5},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Epidermal peels isolated from sunflower hypocotyls provide a convenient model to study the relationship between cortical microtubule orientation and strain rate. Extension of peels can be modulated using chemical treatment and mechanical stress, i.e., by adding a chemical to the incubation medium and applying a load exceeding the yield threshold for irreversible (plastic) strain. In this study, peels were pre-incubated for ca. 12 h (long-term pre-incubation) or for 1 h (short-term pre-incubation). In the long-term pre-incubated peels, fusicoccin applied to the medium neither enhanced the rate of longitudinal plastic strain of loaded peels, nor affected microtubule orientation. However, fusicoccin increased the strain rate of short-term, pre-incubated peels and affected microtubule orientation in both extending (loaded) and non-extending (unloaded) peels. Without fusicoccin, microtubule orientation was generally longitudinal or steep, whereas in fusicoccin-treated unloaded peels it was transverse and oblique microtubules in peel portions corresponding to the apical part of the hypocotyl. Although the frequency of transverse orientation was increased through loading, there was no strong correlation between the rate of fusicoccin-induced strain and microtubule orientation. It is hypothesized that the insensitivity of long-term pre-incubated peels to fusicoccin with respect to strain rate is due to a lack of active plasma membrane H+-ATPases. Thus, the sensitivity of short-term, pre-incubated, unloaded (non-extending) peels to fusicoccin, with respect to microtubule orientation, indicates that orientation might be affected by electric currents resulting from fusicoccin stimulation of H+-ATPases. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.
2010
Burian, A.; Hejnowicz, Z.
Strain rate does not affect cortical microtubule orientation in the isolated epidermis of sunflower hypocotyls Journal Article
In: Plant Biology, vol. 12, no. 3, pp. 459-468, 2010, (5).
@article{2-s2.0-77955789917,
title = {Strain rate does not affect cortical microtubule orientation in the isolated epidermis of sunflower hypocotyls},
author = { A. Burian and Z. Hejnowicz},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955789917&doi=10.1111%2fj.1438-8677.2009.00228.x&partnerID=40&md5=94e40ceb05f2af707414ac1566f344cb},
doi = {10.1111/j.1438-8677.2009.00228.x},
year = {2010},
date = {2010-01-01},
journal = {Plant Biology},
volume = {12},
number = {3},
pages = {459-468},
abstract = {A hypothesis exists that external and internal factors affect the orientation of cortical microtubules in as much as these lead to changes in cell elongation rate. Factors that stimulate elongation are proposed to lead to transverse microtubule orientation, whereas factors that inhibit elongation lead to longitudinal orientation. The elongation rate is equal to the rate of longitudinal irreversible strain in cell walls. Incubated epidermis peeled from sunflower hypocotyls does not extend unless it is stretched by loading and the pH of the incubation medium is appropriately low. Thus, peels provide a convenient model to investigate the relationship between longitudinal strain rate and cortical microtubule orientation. In the present study, it was found that peeling affects microtubule orientation. Peels were incubated for several hours in Murashige & Skoog medium (both unbuffered and buffered) to attain a steady state of microtubule orientation before loading. The effects of loading and pH on strain rate and orientation of microtubules under the outer epidermal walls were examined in three portions of peels positioned with respect to the cotyledonary node. Appropriate loading caused longitudinal strain of peels at pH 4.5 but not at pH 6.5. However, no clear effect of strain rate on microtubule orientation in the peels was observed. Independent of applied load and pH of the incubation medium, the microtubule orientation remained unchanged, i.e. orientation was mainly oblique. Our results show that strain rate does not affect cortical microtubule orientation in isolated epidermis of the sunflower hypocotyl model system, although orientation could be changed by white light. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.},
note = {5},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A hypothesis exists that external and internal factors affect the orientation of cortical microtubules in as much as these lead to changes in cell elongation rate. Factors that stimulate elongation are proposed to lead to transverse microtubule orientation, whereas factors that inhibit elongation lead to longitudinal orientation. The elongation rate is equal to the rate of longitudinal irreversible strain in cell walls. Incubated epidermis peeled from sunflower hypocotyls does not extend unless it is stretched by loading and the pH of the incubation medium is appropriately low. Thus, peels provide a convenient model to investigate the relationship between longitudinal strain rate and cortical microtubule orientation. In the present study, it was found that peeling affects microtubule orientation. Peels were incubated for several hours in Murashige & Skoog medium (both unbuffered and buffered) to attain a steady state of microtubule orientation before loading. The effects of loading and pH on strain rate and orientation of microtubules under the outer epidermal walls were examined in three portions of peels positioned with respect to the cotyledonary node. Appropriate loading caused longitudinal strain of peels at pH 4.5 but not at pH 6.5. However, no clear effect of strain rate on microtubule orientation in the peels was observed. Independent of applied load and pH of the incubation medium, the microtubule orientation remained unchanged, i.e. orientation was mainly oblique. Our results show that strain rate does not affect cortical microtubule orientation in isolated epidermis of the sunflower hypocotyl model system, although orientation could be changed by white light. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.
2007
Burian, A.
Chiral changes of cortical microtubule orientations in epidermis of sunflower hypocotyls. The effect of blue and red light Journal Article
In: Acta Societatis Botanicorum Poloniae, vol. 76, no. 4, pp. 269-275, 2007, (1).
@article{2-s2.0-38549111520,
title = {Chiral changes of cortical microtubule orientations in epidermis of sunflower hypocotyls. The effect of blue and red light},
author = { A. Burian},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38549111520&partnerID=40&md5=4227031f31c1a4de658bdf62ea99d577},
year = {2007},
date = {2007-01-01},
journal = {Acta Societatis Botanicorum Poloniae},
volume = {76},
number = {4},
pages = {269-275},
publisher = {Polish Botanical Society},
abstract = {Light and developmental processes affect the cortical microtubule (cMT) orientation. The cMT orientation with a special regard to its chirality was analyzed under the outer epidermal cell walls in different regions of sunflower hypocotyls kept in darkness and after irradiation with blue and red light. The results show that the cMT orientation depends on the cell position along hypocotyl, but generally cMTs are oblique. The oblique orientation has defined chirality: either of Z-form (right-handed) or S-form (left-handed). In the lower region of hypocotyls the Z-form dominates. After irradiation of hypocotyls with blue light this domination has been maintained and appeared also in the upper region. In contrast, after irradiation with red light the Z-form domination has not been apparent. It is proposed that in darkness, variations of cMT orientations in the epidermis along the hypocotyl are due to developmental processes, while blue and red light affect the cMT orientation via "shifting" these processes backward and forward, respectively.},
note = {1},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Light and developmental processes affect the cortical microtubule (cMT) orientation. The cMT orientation with a special regard to its chirality was analyzed under the outer epidermal cell walls in different regions of sunflower hypocotyls kept in darkness and after irradiation with blue and red light. The results show that the cMT orientation depends on the cell position along hypocotyl, but generally cMTs are oblique. The oblique orientation has defined chirality: either of Z-form (right-handed) or S-form (left-handed). In the lower region of hypocotyls the Z-form dominates. After irradiation of hypocotyls with blue light this domination has been maintained and appeared also in the upper region. In contrast, after irradiation with red light the Z-form domination has not been apparent. It is proposed that in darkness, variations of cMT orientations in the epidermis along the hypocotyl are due to developmental processes, while blue and red light affect the cMT orientation via "shifting" these processes backward and forward, respectively.
2006
Hejnowicz, Z.; Burian, A.; Dobrowolska, I.; Kolano, E.
Orientational variability of parallel arrays of cortical microtubules under the outer cell wall of the Helianthus hypocotyl epidermis Journal Article
In: Acta Societatis Botanicorum Poloniae, vol. 75, no. 3, pp. 201-206, 2006, (1).
@article{2-s2.0-33750743737,
title = {Orientational variability of parallel arrays of cortical microtubules under the outer cell wall of the Helianthus hypocotyl epidermis},
author = { Z. Hejnowicz and A. Burian and I. Dobrowolska and E. Kolano},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750743737&partnerID=40&md5=041c1af7187a88f5ca4b7ba1e9b80525},
year = {2006},
date = {2006-01-01},
journal = {Acta Societatis Botanicorum Poloniae},
volume = {75},
number = {3},
pages = {201-206},
publisher = {Polish Botanical Society},
abstract = {The epidermis of Helianthus hypocotyl can be peeled off and, in the form of detached strips can be used as a model system to study the effect on cortical microtubule (cMTs) orientation of these factors, which are difficult to be manipulated in situ, such as apoplastic pH or applied stress. In the first step, however, the orientation and reorientation of cMTs in the epidermis in situ must be described. The cMTs under the epidermal wall in hypocotyl epidermis at different positions along the hypocotyl and on its opposite sides were studied by means of immunostaining, using epi-fluorescence microscopy. The angle λ that parallel array of cMTs makes with cell longitudinal axis was measured. The variation of λ in a population of cells was documented by λ-histogram (frequency of cells exhibiting a particular λ±Δλ plotted against λ value). The histograms were of either transverse type (maximum at λ ∼90°; denoted as type A) or oblique type (two maxima on both sides of the transverse direction; denoted as type B) in the apical part of the hypocotyl, and were either of B type or of longitudinal type (maximum at λ ∼0° or 180° denoted as type C) in the basal part. The change from A or B to C basipetally may be considered as due to the developmental trend in cMT orientation. The occurrence of B above A in some hypocotyls in their apical part strengthens the hypothesis on the autonomous reorientation of cMTs. The intermingled occurrence of A and B reorientation in the upper part of hypocotyl is interpreted as a manifestation of a subtle control of cell growth in latitudinal direction. The majority of histograms were asymmetric showing predominance of cMT parallel arrays inclined as the middle part of the letter Z.},
note = {1},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The epidermis of Helianthus hypocotyl can be peeled off and, in the form of detached strips can be used as a model system to study the effect on cortical microtubule (cMTs) orientation of these factors, which are difficult to be manipulated in situ, such as apoplastic pH or applied stress. In the first step, however, the orientation and reorientation of cMTs in the epidermis in situ must be described. The cMTs under the epidermal wall in hypocotyl epidermis at different positions along the hypocotyl and on its opposite sides were studied by means of immunostaining, using epi-fluorescence microscopy. The angle λ that parallel array of cMTs makes with cell longitudinal axis was measured. The variation of λ in a population of cells was documented by λ-histogram (frequency of cells exhibiting a particular λ±Δλ plotted against λ value). The histograms were of either transverse type (maximum at λ ∼90°; denoted as type A) or oblique type (two maxima on both sides of the transverse direction; denoted as type B) in the apical part of the hypocotyl, and were either of B type or of longitudinal type (maximum at λ ∼0° or 180° denoted as type C) in the basal part. The change from A or B to C basipetally may be considered as due to the developmental trend in cMT orientation. The occurrence of B above A in some hypocotyls in their apical part strengthens the hypothesis on the autonomous reorientation of cMTs. The intermingled occurrence of A and B reorientation in the upper part of hypocotyl is interpreted as a manifestation of a subtle control of cell growth in latitudinal direction. The majority of histograms were asymmetric showing predominance of cMT parallel arrays inclined as the middle part of the letter Z.