| As a key grain crops, peple has pay much attention to increase the yield and quality of wheat for a long time. Using plant growth regulators to change the system of endogenous hormones and regulate the growth and development of plant is a good method to improve the growth and yield of plant. This method is called chemical regulation cultivation technology. There are many researches focused on the effects of different plant growth regulators on the growth and development of wheat; but most of them are limited on the control of one growth stage of plant. The yield and qaulity of plant are not the result of one stage, but the comprehensive effects of each stage. As the growth of plant, their growth centre is changing; the metabolic characteristics and growth and development characteristics is also changed. Therefore, using different regulating methods in different stages is one of the effective mesures to coordinate the relationship between plant growth and the enviroment, and to improve the water and nutrient use efficency of plant. Furthermore, the effect of plant growth regulation is related to the nutritional status of plant; but there is little research about the effects of different nutrition and chemical regulation on plant.This research used the field experiment methods to evaluate the effects of different plant growth regulators and different nitrogen fertilization on the growth, yield, and nutrient uptakes and utilizations of winter wheat. The main results were shown as following:1. A field experiment designed with a split-plot design method was conducted to study the effects of the application rates of nitrogen, plant growth regulators, and the varieties of winter wheat on the growth and development, and grain yield and its constituents. The result showed that the treatment of PP333 increased the number of tillers per plant in winter and spring. And the treatments with PP333 addition decreased the length of the first and second internode, and increased the lodging-resistance of wheat and the blade chlorophyll contents of wheat. After the spray of 6-BA at the beginning of grian-filling stage, it greatly increased the chlorophyll contents, and delayed senescence of wheat, and extended the period of grain filling, and increased the grain number per plant and 1000-grain weight; and the yield was obviously improved by using plant growth regulators in different growth phase. It was more effective in the soil with middle or low fertility. Cultivars xiaoyan No.22 was sensitive to 6-BA, whereas xiaoyan No.6 was opposite; and xiaoyan No.6 was sensitive to PP333.2. A field experiment designed with nitrogen fertilization was conducted to study the effects of different nitrogen fertilization land chemical regulation measures on physiological index and yield of winter wheat. The result shows that the content of chlorophyll and photosynthetic rate were increased significantly by nitrogen application, although they didn't increase when the amount of nitrogen application increased, it's similar for the transpiration rate and stomatal conductance, but intercellular CO2 concentration was opposite, and apply nitrogen increased the yield, grains per ear and ear per mu significantly, but the 1000-grain weight has been decreased. Spray 6-BA at the stage of flowering benefit for chlorophyll content increasing and photosynthesis, but had little effect on the yield and it's constituents. Spray ethephon at milk stage decreased the chlorophyll content but the content of soluble sugar was more than the water treatment, and spray ethephon has little effect on the yield and its composition. It is concluded that the yield of winter wheat and physiological index after flowering could be improved by the plant growth regulators, nutrients and cultivations. 3. A field experiment designed with nitrogen fertilization was conducted to study the effects of different nitrogen fertilization and plant growth regulators on the nutrient uptakes and utilization of winter wheat. The result showed that the accumulative amount of nitrogen, phosphorus and potasium in stem, blade, glume and grain were increased significantly by nitrogen application, although the difference between 240 kg/hm2 nitrogen application and 120kg/hm2 nitrgen application of the accumulative amount of N, P and K in grain was not significantly. The distribution proportion of nutrients in blade was increased significantly by nitrogen application; but the ditribution proportion of nutient in grain was decreased significantly. And the manifestations of ditribution proportion in stem and Glume were different as the nutrient elements. The use efficiency of nitrogen was decreased significantly by nitrogen application, while the use efficency of phosphorus was increased significantly, altough it would decrease when apply excessive nitrogen. There was little effect on the potasium use efficency. As the amount of nitrogen increased, the nutrient harvest decreased significantly. Spray 6-BA at the stage of flower stages promoted nitrogen and phosphorus uptake of wheat; and had little effect on the potasium absorption. Also spray 6-BA had no effect on the distribution proportion, use efficency and havest index of nutrients. Spray ethephon under the application of 240 kg/hm2 of nitrogen fertilizer had little effect on the uptake, ditribution proportion, use efficency and havest index of nutrients. |
