The Effects Of Water Stress On The Growth And Physiological Indexes Of Maize

Drip irrigation is an advanced technique. It has the advantages of saving water, enhancing yields, upgrading quality and high utility. Along with the development of agriculture, water-saving irrigation technologies are used more and more widely. So it is a key to establish suitable moisture content of crops under different water stress in order to realize accurate and scientific irrigation. In this paper, we take the corn as the test material, by using the method of rain water control of drip irrigation under membrane, effect of water stress on morphology and physiological characteristics of maize, the morphological index, photosynthetic index, chlorophy Ⅱ fluorescence index, yield and quality index of maize were analyzed under different water stress conditions, the sensitive index of maize was explored under water stress, Which provided the basis for guiding the precision irrigation of farmland. The main conclusions are as follows:(1) In the jointing stage, the effect of different water stress on plant height was significant, but the effect on leaf area was not significant; in the tasseling stage, the effect of different water stress on plant height, leaf area was significant, the degree of water stress was smaller, and the growth of maize was better. Using canonical correlation analysis, in the jointing stage, when the soil moisture content of 60%θf-65%θf, the morphology indexes of maize have reached a good level, the plant height is under water stress was the most sensitive index.(2) The photosynthetic rate and transpiration rate of maize were decreased by water stress, the greater the degree of water stress, the greater the decrease of photosynthetic rate (Pn) and transpiration rate (Tr). The photosynthetic intensity of the tasseling stage was higher than that of the jointing stage, the Pn and Tr of maize under the same water stress in the jointing stage was more sensitive than in the tasseling stage, the water use efficiency of maize leaves under water stress was increased, and the water use efficiency was significantly higher in the tasseling stage than that in the jointing stage. When subjected to water stress, maize is mainly used to improve water use efficiency by reducing its transpiration rate. The relationship between photosynthetic indexes and soil water content was studied by canonical correlation analysis. The transpiration rate was the most sensitive index of water stress at the jointing stage, and the photosynthetic rate was the most sensitive index of water stress.(3)During the maize jointing, When soil moisture is 60%θf～65%θf of field capacity, the canonical correlation coefficient between maize chlorophy Ⅱ Fluorescence parameters and soil moisture is 0.829. which is very significant. PS Ⅱ potential activity Fv/FO is the most sensitive to soil moisture. During the maize tasseling, when soil moisture is 60%θf～65%θf of field capacity, the canonical correlation coefficient is 0.870, which is very significant. And PS Ⅱ photochemical efficiency Fv/Fm is the most sensitive to soil moisture.(4) The effect of water stress on yield and composition of maize reached a significant level at jointing and tasseling stage. Grain number, one hundred seed weight and water use efficiency of maize in jointing stage under water stress is extraction larger than in tasseling stage, and with the stress level increasing, the grain number, one hundred seed weight and water use efficiency decline increased. Different water stress effects on the quality of maize (starch and protein)reached significant level, and effect on fat did not reach significant level, water stress degree is high, protein, fat and starch decreased more.(5)The relationship between water stress sensitivity index and yield and quality was studied by canonical correlation analysis. PS Ⅱ potential activity Fv/FO was the most sensitive index of yield and quality at the jointing stage, and the photosynthetic rate was the most sensitive index of yield and quality. Using of normalization method will yield, water use efficiency and quality of water stress to do a comprehension evaluation, it is concluded that the drip irrigation under mulch soil moisture was 60-65% θf as the most suitable soil moisture.