Plant movement.: Submergence-induced petiole elongation in Rumex palustris depends on hyponastic growth
Plant movement.: Submergence-induced petiole elongation in Rumex palustris depends on hyponastic growth
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DOI：
10.1104/pp.102.014548
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发表时间：
2003-05-01
期刊：
影响因子：
7.4
通讯作者：
Voesenek, LACJ
中科院分区：
文献类型：
--
作者：
Cox, MCH;Millenaar, FF;Voesenek, LACJ
耐淹种沼泽酸模Rumex palustris(Sm.)通过增加叶柄与水平线的夹角来响应完全淹没。这种次生性生长，与刺激的叶柄伸长相结合，可以使叶尖浮出水面，从而恢复气体交换，使之得以存活。利用计算机数码相机装置，研究了这种亚音速叶柄运动和刺激的叶柄伸长的动力学。亚音速生长是一个相对较快的过程，在1.5~3h的滞后期开始，6~7h后完成。亚音速生长的动力学取决于浸水时叶柄的初始角度，这是一个具有较大季节性变化的因素。例如，淹水时较小的叶柄角度会导致较短的低速生长滞后期。这种次音速生长动力学的依赖性可以通过在浸水时通过实验操纵叶柄角度来模拟。受刺激的叶柄伸长对完全淹水的响应也表现出依赖于淹水时的叶柄角度的动力学，较小的初始叶柄角度导致叶柄伸长的滞后期较长。角度操纵实验表明，只有当叶柄的角度达到40度至50度时，刺激的叶柄才能开始伸长。叶柄可以达到这个通过低速生长过程刺激叶柄伸长的“临界角”。这项研究表明，沼泽红藻对淹水的一种反应(受刺激的叶柄伸长)对另一种反应(低速的叶柄生长)具有功能依赖性，因为只有当叶柄或多或少处于直立位置时，叶柄伸长才能促使叶片到达水面。
The submergence-tolerant species Rumex palustris (Sm.) responds to complete submergence by an increase in petiole angle with the horizontal. This hyponastic growth, in combination with stimulated elongation of the petiole, can bring the leaf tips above the water surface, thus restoring gas exchange and enabling survival. Using a computerized digital camera set-up the kinetics of this hyponastic petiole movement and stimulated petiole elongation were studied. The hyponastic growth is a relatively rapid process that starts after a lag phase of 1.5 to 3 h and is completed after 6 to 7 h. The kinetics of hyponastic growth depend on the initial angle of the petiole at the time of submergence, a factor showing considerable seasonal variation. For example, lower petiole angles at the time of submergence result in a shorter lag phase for hyponastic growth. This dependency of the hyponastic growth kinetics can be mimicked by experimentally manipulating the petiole angle at the time of submergence. Stimulated petiole elongation in response to complete submergence also shows kinetics that are dependent on the petiole angle at the time of submergence, with lower initial petiole angles resulting in a longer lag phase for petiole elongation. Angle manipulation experiments show that stimulated petiole elongation can only start when the petiole has reached an angle of 40degrees to 50degrees. The petiole can reach this "critical angle" for stimulated petiole elongation by the process of hyponastic growth. This research shows a functional dependency of one response to submergence in R. palustris (stimulated petiole elongation) on another response (hyponastic petiole growth), because petiole elongation can only contribute to the leaf reaching the water surface when the petiole has a more or less upright position.