Gravitropism in higher plants
Gravitropism in higher plants
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DOI：
10.1104/pp.120.2.343
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发表时间：
1999-06-01
期刊：
影响因子：
7.4
通讯作者：
Masson, PH
中科院分区：
文献类型：
--
作者：
Chen, RJ;Rosen, E;Masson, PH
自1806年以来，我们已经知道植物器官利用重力作为生长的指南（Knight，1806）。重力导向的生长过程，称为向重力性，指示向上的枝条生长，以确保叶片的正确定位，以进行有效的光合作用和气体交换。它还能引导植物的根向下生长，在土壤中，它们可以伸展出去吸收植物生长发育所需的水分和矿物质离子。向重力性对农业有重要影响。它允许植物竞争其直接环境中的有限资源，并确保作物芽在风雨作用下枯萎后恢复向上生长（图1）。因此，植物可以使种子远离土壤水分和病原体，更适合机械收获。世纪末，Ciesielski（1872）和达尔文（1880）证明了根顶端的一种结构，即根帽，是根向地性所必需的。他们假设根冠可以感知到在重力场（重力刺激）内根尖方向的变化。然后，重力感知将产生生理信号，该信号在传输到伸长区时将促进相对侧腹上的差异细胞伸长，这是导致弯曲发展的原因。由此产生的曲率将使根尖能够沿着向重力更可接受的矢量恢复生长。
Since 1806, we have known that plant organs use gravity as a guide for growth (Knight, 1806). The gravity-directed growth process, called gravitropism, dictates upward shoot growth to ensure a proper positioning of the leaves for efficient photosynthesis and gas exchange. It also directs roots to grow downward in soil, where they can reach out to take up the water and mineral ions required for plant growth and development.Gravitropism has an important impact on agriculture. It allows plants to compete for the limited resources available in their immediate environment and ensures that crop shoots resume upward growth after prostration by the action of wind and rain (Fig. 1). Consequently, plants can keep their seeds away from soil moisture and pathogens and are more amenable to mechanical harvesting. At the end of the 19th century, Ciesielski (1872) and Darwin (1880) demonstrated that a structure at the tip of the roots, the cap, is essential for root gravitropism. They postulated that the root cap could perceive a change in root-tip orientation within the gravitational field (gravistimulus). Graviperception would then produce a physiological signal that, upon transmission to the elongation zone, would promote a differential cellular elongation on opposite flanks, which is responsible for the development of a curvature. The resulting curvature would allow the root tip to resume growth along a gravitropically more acceptable vector.