Developmental responses of crop root system to water stress and its physiological basis

本研究旨在探讨作物根系对水分胁迫的响应。特别注意了组成根系的各组分根系所表现出的塑性响应。首先对水稻根系在不同水分条件下的发育和功能可塑性进行了评价。水分机制包括土壤水分波动，如水分胁迫后再浇水模拟干旱后的降雨，以及涝渍，干旱，然后再浇水模拟雨养低地条件。接下来，我们研究了水分胁迫对玉米、豇豆和水稻根系衰老和翻代的影响。最后，对甘薯块根在水分胁迫条件下的供水能力进行了定量评价。结果表明，土壤水分条件对根系发育和形态的影响较大，根系具有较大的可塑性，保证了植物在水分胁迫下的生长，根系表现出的可塑性是各组分根系对胁迫的差异化响应的综合结果。此外，我们还发现甘薯块根在土壤干燥时对地上部的供水可能起着重要的作用。这些研究结果为根系在作物抗旱性中的作用提供了依据，并有望为干旱易发地区抗旱性育种计划和生产技术的进展做出贡献。

This study aimed to investigate the responses of crop root system to water stress. Special attention was paid to plastic responses exhibited by component roots that consist of the root system.Specifically, first developmental and functional plasticity of rice root system to various water regimes was evaluated. The water regimes included soil moisture fluctuations such as water stress followed by rewatering simulating raining after drought, and waterlogging, drought and then rewatering simulating rainfed lowland conditions. Next, we examined the effects of water stress on senescence and turn over of root system for maize, cowpea and rice. Finally, we attempted to quantitatively evaluate the water supply ability of root tuber of sweetpotato under water stress conditions.Results revealed that root system development and morphology are greatly affected by soil water conditions, such large plasticity of root system ensures the growth of plant under water stress, and the plasticity exhibited by the root system is the integrated results of differentiated responses of component roots to the stress. Further, we found that root tuber of sweetpotato may play a substantial role in supplying water to shoot especially when soil dries. These findings provides with bases on the role of root system in crop drought tolerance, and are expected to contribute to the progress of breeding program for drought tolerance and production technology in drought prone areas.