Growth, yield and biochemical response of rice cultivars to low light and high temperature-humidity stress

摘要

Low light stress alone (65 percent NL) in general caused significant increase in the stature and foliage growth of rice plants, while decreased the biological and economic yield remarkably in all the rice cultivars. However, low light coupled with high temperature (38 deg C) and humidity (RH 94 percent) induced complete spikelet sterility, enhanced foliage growth and impaired the biological yield. Lower biological and economic yield recorded under low radiation was mainly due to significant reduction in the number of panicles plant~(-1) and grains panicle~(-1), whereas zero economic yield under low radiation with high temperature and humidity was attributed to complete spikelet sterility. Among the rice genotypes tested, Mansarover showed greatergrowth and yield stability under low radiation. Rice cultivars also showed differential biochemical response to such environmental stress. Generally the low light stress alone or with high temperature and humidity enhanced the level of chlorophyll and organic nitrogen significantly, but depleted the level of sugars, starch, RNA and hemicellulose in rice genotypes.