Adjustment Responses of Crop Plants to Environmental Stress and its Strategies for Adaptation

为了更好地了解作物对胁迫环境的适应策略，该小组的研究人员研究了不同胁迫条件下作物的适应性形态发生及其生理机制。主要研究结果如下：在水稻植株中，不同环境条件下收获的种子萌发特性不同，幼苗生长方式可分为7种类型，与耐深播性有关。土壤施入可溶性淀粉导致根系活力降低，导致光合作用速率下降，上部合成的脱落酸向根内转移，影响根系生长。此外，在水分胁迫条件下，不同谷类作物的根系可塑性也不同。在白薯中，茉莉酸对块茎的形成起着重要的作用，在干旱条件下，根质量小的品种的蒸腾速率明显低于根质量大的品种。在甘薯中，淀粉的合成受ADPGPPase调控。大豆初花期喷施烯效唑磷肥提高了大豆的光合作用速率和叶片厚度。高粱在长日照和高温条件下，抽穗期明显延迟。在番茄中，即使在光照和地上部温度足够的情况下，地上部的生长也受到较低根温的限制。豆科作物在弱光条件下生长，叶片韧皮部负载量下降，光合作用速率下降。

For better understanding of the strategies in crop plants for adaptation to stress environments, the researchers of this group investigated the adaptative morphogenesis together with the physiological mechanisms in various stress conditions. The main results obtained were summarized as follows ; In rice plant, the germination characteristics were different in the seeds harvested in various environmental conditions, and the growth pattern of seedlings was divided into 7 types related with the tolerance to deep sowing. The low root activity caused by soluble starch application to soils declined photosynthetic rate, and the abscisic acid synthesized in top translocated into root and effected root growth. In addition, the plasticity of root system was different in cereal species under water stress conditions. In white potato, jasmonic acid playd an important role on tuberization, and the transpiration rate in a variety with small root mass greatly decreased under drought conditions when compared with a variety with large root mass. In sweet potato, starch biosynthesis was regulated by ADPGPPase. In soybean, Uniconazole-P application at initial flowering stage increased photosynthetic rate together with leaf thickness. In sorghum, heading stage was greatly delayd at long-day and high temperature conditions. In tomato, shoot growth was restricted by low root temerature, even if radiation and shoot temperature were adequate. The phloem loading of leaves in the leguminous crops decreased together with photosynthetic rate when grown under low light conditions.