Complex physiological and molecular processes underlying root gravitropism
Complex physiological and molecular processes underlying root gravitropism
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DOI：
10.1023/a:1015294711391
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发表时间：
2002-06-01
影响因子：
5.1
通讯作者：
Masson, PH
中科院分区：
文献类型：
--
作者：
Chen, R;Guan, CH;Masson, PH
向地性允许植物器官根据重力矢量引导其生长。对于大多数根来说，这种对重力的反应允许向下生长到土壤中，那里有水和养分可供植物生长和发育。根中重力感应的主要部位包括根冠，并且似乎涉及小柱细胞内淀粉体的沉积。这一过程触发信号转导途径，促进小柱细胞周围壁的酸化、小柱细胞质的碱化以及根冠横向极性的发展，从而建立横向生长素梯度。然后，该梯度被传输到伸长区域，在那里它触发中央伸长区域相对侧翼上的差异细胞伸长，负责部分向重力曲率。最近的研究结果还表明，根部重力感应的次要位点/机制参与了向地性，并且重力响应的早期阶段（涉及远端伸长区相对侧翼的差异伸长）可能与生长素梯度无关。这篇综述讨论了我们目前对根向重力反应各个阶段的分子和生理机制的理解。
Gravitropism allows plant organs to guide their growth in relation to the gravity vector. For most roots, this response to gravity allows downward growth into soil where water and nutrients are available for plant growth and development. The primary site for gravity sensing in roots includes the root cap and appears to involve the sedimentation of amyloplasts within the columella cells. This process triggers a signal transduction pathway that promotes both an acidification of the wall around the columella cells, an alkalinization of the columella cytoplasm, and the development of a lateral polarity across the root cap that allows for the establishment of a lateral auxin gradient. This gradient is then transmitted to the elongation zones where it triggers a differential cellular elongation on opposite flanks of the central elongation zone, responsible for part of the gravitropic curvature. Recent findings also suggest the involvement of a secondary site/mechanism of gravity sensing for gravitropism in roots, and the possibility that the early phases of graviresponse, which involve differential elongation on opposite flanks of the distal elongation zone, might be independent of this auxin gradient. This review discusses our current understanding of the molecular and physiological mechanisms underlying these various phases of the gravitropic response in roots.