The onset of rapid cell elongation occurred at different distances from the apex in various tissues of the primary root of maize (Zea mays L.). Furthermore, the comparison of these distances with those determined for the cessation of mitotic divisions revealed a considerable discrepancy. The onset of rapid cell elongation was realized much farther from the root apex than the cessation of cell divisions and therefore a distinct region could be distinguished in every examined maize root tissue. This region was denoted the region of postmitotic 'isodiametric' cell growth. Cells in this region grew in width as well as in length and obtained approximately a square-isodiametric shape. They were also characterized, as are cells in the meristem, by intense nucleic-acid metabolism. This prominent postmitotic 'isodiametric' cell growth was observed in both polyploid and diploid tissues, and indicates that postmitotic 'isodiametric' cell growth, like mitotic division and cell elongation growth, represents an important developmental stage in plant cell ontogeny.

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Rapid reorganization of microtubular cytoskeleton accompanies early changes in nuclear ploidy and chromatin structure in postmitotic cells of barly leaves infected with powdery mildew. Baluska, F.; Bacigalova, K; Oud, J.L.; Hauskrecht, M.; Kubica, S. Published in: Protoplasma DOI:10.1007/BF01272854 Link to publication Citation for published version (APA):Baluska, F., Bacigalova, K., Oud, J. L., Hauskrecht, M., & Kubica, S. (1995). Rapid reorganization of microtubular cytoskeleton accompanies early changes in nuclear ploidy and chromatin structure in postmitotic cells of barly leaves infected with powdery mildew. Protoplasma, 185, 140-151. DOI: 10.1007/BF01272854 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Summary. Post-mitotic ePidermal cells of barley leaves were found to contain, in addition to cortical microtubules (CMTs), distinct arrays of endoplasmic microtubules (EMTs). These encircle nuclei and continuously merge into the CMT arrays that underly the plasmalemma. Detailed three-dimensional reconstruction of both types of MTs during fungal infection showed that profound and very rapid MT rearrangements occurred especially in the case of incompatible (resistant) barley-powdery mildew genotype combination. The most early MT responses, followed by their subsequent complete disintegration, were recorded around nuclei. These events might be relevant for the induction of such nuclear processes as onset of DNA synthesis and nuclear chromatin condensation. Observed pattern of early infection events, as well as less prominent responses in the case of compatible (susceptible) barley-powdery mildew genotype combination, both findings suggest that rapid reorganization of the MT cytoskeleton could be involved in recognition of the fungus by host cells and in the initiation of resistance responses in barley leaves. We hypothesize that the integrity and dynamics of the MT cytoskeleton, especially of its perinuclear part, might participate in control mechanisms involved in activation of resistance genes.