Differences Of Water Use Characters And Relevant Mechanisms For Dominant Winter Wheat Veriaties In Huang-Huai-Hai Plain

Seven representative winter wheat cultivars cultivated widely in Huang-Huai-Hai Plain were selected as research materials. With experiments carried out in leaching buckets under rain shelter and plots in field separately, water consumption features, agronomic traits, photosynthetic characteristics, Antioxidant enzyme system, and Photosynthetic enzymes of the seven cultivars under different water situations were investigated. The experiments was carried out during 2012~2013 and 2013~2014 winter wheat growing seasons in Irrigation Experiment Stations of Guangli Irrigation District(35°40′N, 112°55′E). The main results were as followings:(1) Zhoumai 22, Aikang 58, Luohan 7 and Jimai 22 gained higher grain yield and WUE under suitable water application(CK). Xinmai 26, Shimai 15 and Hengguan 35 gained higher WUE under mild water deficit(MD), by less water consumption and higher grain yields. Under serious water deficit(SD), the WUE values were higher than those under CK treatments, but the grain yields decreased significantly.(2) there are significant differences for tolerances of photosynthetic rate(Pn), stomatal conductance(Gs) and transpiration rate(Tr) to water deficits among the seven cultivars. The photosynthetic capacity of Xinmai 26 performed the best tolerance to water deficits, by a higher stability under different water application treatments. Aikang 58, Luohan 7, Shimai 15 and Hengguan 35 also shown good tolerance capacities to water deficit. Jimai 22 and Zhoumai 22 performed better photosynthetic capacity under CK treatment and lower photosynthetic rates under MD and SD treatments, which showed a weaker tolerance to water deficit.(3) Activity of SOD was more sensitive than other three enzymes to water application. The activity of antioxidant enzyme under mild water deficit was higher than that under CK, but was significantly lower than that under serious water deficit. Water deficit raised the activities of RUBPase and SPS in flag leaf, which was helpful for photosynthesis and grain yield. Higher nitrogen level might improve drought resistance of winter wheat cultivars by decreasing the activities of antioxidant enzyme system in flag leaves. Aikang 58, Xinmai 26 and Shimai 15 performed better drought resistance than Zhoumai 22, because of the activities of antioxidant enzymes and photosynthetic related enzymes for the three cultivars were significantly lower than those for Zhoumai 22.(4) In field experiment, grain yields and WUE values of Xinmai 26, Hengguan 35 and Shimai 15 under mild water deficit were higher than those gained under CK treatment, and Pn, Gs and Tr values for the three cultivars were also higher than those for other cultivars under water deficit. In bucked experiment, the activities of antioxidant enzymes of Xinmai 26 and Shimai 15 were lower than that of Zhoumai 22 under water deficits. Xinmai 26, Hengguan 35 and Shimai 15 performed better drought tolerances than other winter wheat cultivars. Meanwhile, Jimai 22 and Zhoumai 22 performed relatively better under suitable water application(CK) and worse under water deficits for physiological index, yields and WUE values, which showed weaker drought tolerances for the two cultivars. Aikang 58 showed a very good stability in the experiments, because it performed with little variation for physiological index, yields and WUE values under different water application treatments...