Effects Of Water Stress On The Photosynthesis And Yield Characteristics Of Maize In Different Fertility

Because of global climate has changed the drought increasingly had confined the corn produced of Heilongjiang provice.In this paper three water levels including severe drought, light drought, and normal were designed to study the drought-resistance of maize. Morphological and ecological responses of maize to water stress were also researched, especially photosynthesis, transpiration changing rule and chlorophyll fluorescence characteristics of maize. The major results concluded as following.1. The effect of water stress on the growth of maize was significant, including plant highest growing rate, root/top ratio, and efficiency of water application. Water stress decreased the height of maize. Proper drought condition in the earlier stage and normal water supplication in later stage had advantage of improving the efficiency of water utilization.2. Water stress affected the photosynthesis rate of maize in two ways. One was that the photosynthesis rate of maize was restrained, but changing trend in days in light drought condition was similar as in normal water condition. The other way was that photosynthesis rate reached the maximum value in day before the illumination intension reached the highest value in the severe drought condition. Dry material accumulation ability had strong dependence on water condition. In addition transpiration rate also had the similar disciplinarian as the photosynthesis rate.3. Chlorophyll fluorescence, which is the dynamic parameter of maize response to water stress, can sensitively reflect the destroy condition of photosystemâ…¡and light attraction, transform, and utilization. But since the affection factor is rather complicate sometime the effective engendered by water stress can not perfectly reflect the measurement result. If selecting the proper measurement time and accelerating the measurement rate, the variable fluorescence and PSâ…¡photochemical efficiency are the ideal draught-resistance index. In addition, fertilizer application level also affected the chlorophyll fluorescence parameters in certain degree. Increasing fertilizer-dressing levels had the advantage of decreasing the damage of water stress to PSâ…¡.4.Acording to water stress affected the crop yield rate of maize, effect of water stress on the crop yield was sensitive if give the maize water stress during teaseling stage to mature stage...