Impact of Chilling Temperature and Drought on Corn Physiological Process in Seedling Stage

Northeast China is a frequently occurring area of agricultural meteorological disasters, where chilling temperature and drought frequently happen simultaneously, which brings about a greater impact on the growing up process and grain yield of corn and other crops. Therefore, they are paid more attention to. However, the researches in the past are mostly of the single weather disaster of either chilling damage or drought, seldom considering their combining impacts on corn growing up process. From this view point, combining impacts of chilling damage and drought on corn physiological process are undertaken with its growing up process in seeding stages.The experiment is carried out in the artificial weather laboratory of crops cultivating institute of Heilongjiang Agricultural Academy in 2004, where the mode of cultivating corn in a pot is adopted and the corn being cultivated is treated with chilling damage and drought respectively in its seeding stages. Through artificial simulation experiment, the impact of chilling damage, drought and their combining on corn physiological process, growing up process in seeding stages are quantitatively studied. Results are as follows:the impacts of chilling damage on photosynthesis and transpiration rate are both negative effects; photosynthesis rate assumes a conic section correlation with temperature. Transpiration rate assumes a cublic section corvelation. When the field water capacity is 80% and the temperature drops from 20 ℃ to 16 ℃, photosynthesis rate decreases by 22.4% and transpiration rate decreases by 44.0%; impacts of drought on photosynthesis and transpiration rate are also negative effect; both photosynthesis rate and transpiration rate assumes a conic section correlation with soil moisture. when the temperature is 20 ℃, the photosynthesis rate decreases by 11.5% from 80% of field water capacity to 50% and transpiration rate decreases by 2.7% from 60% of field water capacity to 50%; the combining impacts of chilling damage and drought are far greater than the impacts of single factor of chilling damage or drought; the photosynthesis rate decreases by 32.1% and the transpiration rate decreases by 52.7% when the temperature drops from 20 ℃ to 16 ℃ accompanied by the soil moisture decreases from 80% of field water capacity to 50%.