Analysis on Relationships between Plant Growth and Water Dynamics in Environment-Plant System

通过对植物水分运移、植物水势、植物叶片生长、根系质量交换等植物和水行为的测量，分析了植物生长与植物-环境系统中水动力学的关系。由叶片热平衡测定的蒸发需要量与蒸腾量呈线性相关。蒸发需要量主要取决于短辐射和空气湿度，而不是空气温度和风速。从全株水分平衡随辐射强度的变化来看，除了膨胀压力外，细胞膜导水率和叶片伸伸性也影响植株含水量变化、气孔运动和叶片生长。这些变量对低蒸发需求下的光照反应强烈。在根系中，随着根温的升高，水分传导阻力增大。温度效应可能导致植物蒸腾作用的变化。利用图像处理技术揭示了根长指数增长和温度对叶片生长的影响。利用这些知识，优化农业生产的环境条件是可行的。

Measurements on plant and water behavior, such as weter transport in plant, water potential in plant, plant leaf growth, mass exchange in root system and etc., were carried out to analyze the relationships between plant growth and water dynamics in plant-environment system. Evaporative demand determined from heat balance in leaf was related linearly with measured transpiration. The evaporative demand was depended more largely on short radiation and air humidity than air temperature and air velocity. From the water balance in whole-plant varing with radiation intensity, it was found that hydraulic conductivity through cell membrane and leaf extensibility, besides turgor pressure, also affected on water content variation in plant, stomatal movement, and leaf growth. These variables responded intensively to light exposure at low evaporative demand. In the root system, resistance to water conduction increased with root temperature. The temperature effect suggests to lead to changes in transpiration of plant. Technique using image processing revealed exponential growth of root length and temperature effects on leaf growth. Using by these obtained knowledge, it would be feasible to optimize environmental conditions for agricultural production.