Effect Of Light And Temperature On Photosynthetic Characteristics And Grain Starch Synthesis For Maize In Different Districts

In response to light and temperature resources in different districts of XianYu335(XY335) and ZhengDan(ZD958) are studied by the way of large scale space multi-site experiments in Qitai of Xinjiang-. Yinchuan of Ningxia and Gongzhuling of Jilin. We acquire the physiological mechanism that high yield needs to match light and temperature by analyzing the real-time net photosynthetic rate, light response curves and the synthesis of starch related to enzymes in response to light and temperature in the different districts of the XY335 and ZD958. The mainly results are as follows:1. With the increase of plant density, the light intensity of the XY335 and ZD958 gradually decreases under different density in same district at silking and grain filling stage, and the real-time net photosynthetic rate of the varieties gradually decreases with the decreased of the light intensity too. However, the real-time net photosynthetic rate of the two varieties among different plant density are significant differences (P<0.05) in each district but appears different time period.2. The real-time net photosynthetic rate of the XY335 and ZD958 is significant difference (P<0.05) from the noon 12 to the afternoon 16 under same density in different districts at filling stage but from the morning 10 to the afternoon at grain filling stage. The temperature and light intensity resources in Qitai is more suitable for maize growth and photosynthetic carbohydrate accumulation than in Yinchuan and Gongzhuling. The general light intensity of Yinchuan is higher than that of Gongzhuling, although the temperature is closed in Yinchuan and Gongzhuling. Therefore, the light intensity is restricted to the photosynthesis of the XY335 and ZD958 in Gongzhuling. The differences of light intensity and temperature lead to the differences of net photosynthetic rate for maize among three districts at grain filling stage.3. According to light response curves at silking and grain filling stage, we should plant the XY335 of using strong light because of rich light resources in Qitai or other similar varieties. And because the light in Yinchuan and Gongzhuling is weaker than that of Qitai, the ZD958 of the ability of using not strong can be considered or other similar varieties.4. With the increase of plant density, the ear leaf SPS, SS (cleavage) and AGPase activity in kernels for the XY335 and ZD958 are decreased. Because the net photosynthetic rate is decreased with the increase of plant density, which photosynthetic product provides substrate of the three enzymes.The changes of sucrose, soluble sugar and starch content in kernels can prove that photosynthetic production accumulation reduces in maize, because the net photosynthetic rate decreases with the increase of plant density. Thus those lead to reduce dry matter accumulation.5. The ear leaf SPS, SS (cleavage) and AGPase activity in kernels for the XY335 and ZD958 in Qitai is higher than that of Yinchuan, but the three enzymes in two varieties are higher in Yinchuan than that of Gongzhuling. Because high light intensity is conductive to photosynthetic carbon assimilation in Qitai, which provides sufficient substrate for sucrose and starch synthesis of the three enzymes. The photosynthetic product for maize in Yinchun provides substrate less than in Qitai and more than in Gongzhuling. Because the temperature is very close in Yinchuan and Gongzhuling, which are higher than in Qitai, but the light intensity in Yinchuan is lower than in Qitai, but higher than in Gongzhuling.6. At grain filling stage, the mean temperature in Qitai is lower than that of Yinchuan but higher in Gongzhuling, and the net photosynthetic rate and starch synthesis related to enzymes activity in Qitai are higher than that of Yinchuan and Gongzhuling, because the light intensity and temperature resources provide good climatic conditions for photosynthetic production accumulation and starch synthetic related to enzymes. And the net photosynthetic rate and starch synthesis related to enzymes activity in Yinchuan is higher than that of Gongzhuling. And the inhibition of low temperature on the enzymes activity of related to starch synthesis in Gongzhuling is far more than the high temperature in Yinchuan. Therefore, the light and temperature resources on the growth of maize are superior to the Gongzhuling, and the temperature lower and less sunlight hinder the growth and development and its grain filling stage.