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

研究了作物根系对水分胁迫的响应。特别关注组成根系的组成根所表现出的可塑性反应，首先评价了水稻根系对不同水分状况的发育和功能可塑性。水分状况包括水分胁迫后复水模拟干旱后降雨和涝渍、干旱后复水模拟干旱低地条件等土壤水分波动。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周转的影响。结果表明，土壤水分条件对甘薯块根的发育和形态有很大影响，根系的巨大可塑性保证了植株在水分胁迫下的生长，根系表现出的可塑性是组成根系对胁迫反应差异化的综合结果。此外，我们还发现甘薯的块根在为地上部提供水分方面可能起着重要作用，尤其是在土壤干燥时。这些结果为深入研究根系在作物耐旱性中的作用提供了依据，并有望为干旱地区作物耐旱育种和生产技术的发展做出贡献。

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.