Season-associated modifications in symplasmic organization of the cambium in Populus nigra
Season-associated modifications in symplasmic organization of the cambium in Populus nigra
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DOI：
10.1093/aob/mcp300
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发表时间：
2010-03-01
期刊：
影响因子：
4.2
通讯作者：
Ehlers, Katrin
中科院分区：
文献类型：
--
作者：
Fuchs, Maike;van Bel, Aart J. E.;Ehlers, Katrin
背景与目的胞间连丝（plasmodesma，PD）连接性的改变对植物的生长发育具有重要意义。在这里，研究了形成层原始细胞的重复分裂模式，以跟踪PD网络在成熟过程中的发展。此外，季节性变化进行了调查，以跟踪指标的发展和功能Adaptations.Methods形成层样品的P.nigra树枝，收集在夏季，秋季和春季，化学固定的透射电子显微镜。参数，PD密度（每平方微米细胞壁面积的PD数）和PD频率（每平均细胞壁面积的PD总数），被确定为径向和切向细胞界面沉积的时间order.Key结果数据集，在plasmodesmogram中，显示出很强的变化在PD网络全年。在夏季，高PD数发生在分隔壁，PD倍增后的纵向分裂，下降与进一步发展的木质部和韧皮部侧。在秋季，分隔壁处的PD的数量是低的，因为它们是在随后的切向界面。在春天，第一次细胞分裂与PD数量的大量增加相一致，特别是在分隔壁。只有首字母之间的径向墙全年维护其PD设备。这个功能可以利用识别的初始layer.Conclusions PD网络在形成层通过严格的发展计划，根据季节，这是与不断变化的功能要求。例如，PD数与增殖活性和细胞间信号传导的潜在途径相关。PD数的增加归因于纵向裂变作为一个主要的机制，而在旧的衍生物的下降归因于PD降解。
Background and Aims Alterations of plasmodesma (PD) connectivity are likely to be very important for plant development. Here, the repetitive division pattern of cambial initials in Populus nigra 'italica' was studied to follow the development of the PD network during maturation. Furthermore, seasonal changes were investigated in order to trace indications for developmental and functional adaptations.Methods Cambium samples of P. nigra twigs, collected in summer, autumn and spring, were chemically fixed for transmission electron microscopy. The parameters, PD density (number of PDs per square micrometre cell-wall area) and PD frequency (total number of PDs per average cell-wall area), were determined for radial and tangential cell interfaces deposited in chronological order.Key Results Data sets, presented in plasmodesmograms, show a strong variability in the PD network throughout the year. In summer, high PD numbers occur at the division wall which, after PD doubling by longitudinal fission, decline with further development both at the xylem and the phloem side. In autumn, the number of PDs at the division wall is low as they are in subsequent tangential interfaces. In spring, the first cell division coincides with a massive increase in PD numbers, in particular at the division wall. Only the radial walls between initials maintain their PD equipment throughout the year. This feature can be exploited for identification of the initial layer.Conclusions PD networks in the cambium go through a strict developmental programme depending on the season, which is associated with changing functional requirements. For instance, PD numbers correlate with proliferative activity and potential pathways for intercellular signalling. Increases in PD numbers are ascribed to longitudinal fission as a major mechanism, whereas the decline in older derivatives is ascribed to PD degradation.