Shifting effects of physiological integration on performance of a clonal plant during submergence and de-submergence
Shifting effects of physiological integration on performance of a clonal plant during submergence and de-submergence
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生理整合对克隆植物在浸水和去浸水期间性能的转变影响
DOI：
10.1093/aob/mcu057
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发表时间：
2014-06-01
期刊：
影响因子：
4.2
通讯作者：
Yu, Fei-Hai
中科院分区：
文献类型：
--
作者：
Luo, Fang-Li;Chen, Yue;Yu, Fei-Hai
背景与目的淹没和去淹没是河岸植物由于水位波动而遇到的常见现象，但关于克隆植物的生理整合(相互连接的分株之间的资源共享)在适应这种事件中的作用，人们知之甚少。本研究以空心莲子草为例，验证了生理整合能促进淹水分株生长和光合作用能力，并能促进去淹后恢复的假说。方法将空心莲子草连系无性系在对照条件下(两个分株系统未处理)、半淹水(一个分株系统淹没，一个不淹没)、全淹没(两个分株系统均淹没)、半遮荫(一个分株系统遮荫，另一个不遮荫)和完全遮荫(两个分株系统都遮荫)30d，然后去淹没/去遮荫20d。沉水植物也被遮荫到很低的光照强度，模拟浑浊洪水中的典型条件。去淹20d后，连接对去淹和非淹水分株的生长都没有显著影响，但去淹分株具有较高的可溶性糖浓度，表明代谢活性较高。由于生长和光合作用的快速恢复，从淹水期对淹水分株和非淹水分株的显著整合效应转变到去淹期的微弱影响。淹水/退水条件下的生理整合效应并不比遮荫/去荫条件下的强。结论研究结果表明，淹水条件下河岸无性系植物在淹水后迅速恢复生长和光合作用的能力，不仅是生理整合的有利效应，也是河岸克隆植物得以传播的关键。
Background and Aims Submergence and de-submergence are common phenomena encountered by riparian plants due to water level fluctuations, but little is known about the role of physiological integration in clonal plants (resource sharing between interconnected ramets) in their adaptation to such events. Using Alternanthera philoxeroides (alligator weed) as an example, this study tested the hypotheses that physiological integration will improve growth and photosynthetic capacity of submerged ramets during submergence and will promote their recovery following de-submergence.Methods Connected clones of A. philoxeroides, each consisting of two ramet systems and a stolon internode connecting them, were grown under control (both ramet systems untreated), half-submerged (one ramet system submerged and the other not submerged), fully submerged (both ramet systems submerged), half-shaded (one ramet system shaded and the other not shaded) and full-shaded (both ramet systems shaded) conditions for 30 d and then de-submerged/de-shaded for 20 d. The submerged plants were also shaded to very low light intensities, mimicking typical conditions in turbid floodwater.Key Results After 30 d of submergence, connections between submerged and non-submerged ramets significantly increased growth and carbohydrate accumulation of the submerged ramets, but decreased the growth of the non-submerged ramets. After 20 d of de-submergence, connections did not significantly affect the growth of either de-submerged or non-submerged ramets, but de-submerged ramets had high soluble sugar concentrations, suggesting high metabolic activities. The shift from significant effects of integration on both submerged and non-submerged ramets during the submergence period to little effect during the de-submergence period was due to the quick recovery of growth and photosynthesis. The effects of physiological integration were not found to be any stronger under submergence/de-submergence than under shading/de-shading.Conclusions The results indicate that it is not just the beneficial effects of physiological integration that are crucial to the survival of riparian clonal plants during periods of submergence, but also the ability to recover growth and photosynthesis rapidly after de-submergence, which thus allows them to spread.