Physiological characterization of maize silking delayed by drought stress
Whether maize silk,which can extrude the husk under drought stress,is an important factor affecting pollination and fertilization,which determines the number of kernels,and final yield.In this research,two summer maize varieties i.e.Annong 591 (AN591) and Zhongdan 909 (ZD909),were used as materials to conduct a drought pot experiment at the flowering stage.The physiological mechanism of sucrose metabolism involved in the drought-tolerant elongation of the silk was investigated by examining the effects of drought stress on the morphology of the silk,the sucrose metabolism,the enzyme activities and the photosynthetic parameters of the leaves at the spike position.The results showed that under drought stress,the silking time of AN591 and ZD909 was delayed,and the cell expansion and vigor of the silk decreased significantly.In addition,the net photosynthetic rate (Pn),transpiration rate (Tr) and stomatal conductance (Gs) of the spike leaves of both varieties decreased by more than 20%,while the interstitial CO2 concentration (Ci) showed the opposite trend,indicating that the production capacity of photosyn-thetically assimilated compounds decreased significantly.The content of sucrose in silk was significantly increased,while the contents of glucose and fructose were significantly decreased,and the activities of sucrose synthase and cell wall acid converting enzyme were decreased,indicating that the degradation of sucrose into hexose was severely compromised.In summary,drought stress delayed silking time,which may be caused by the combination of insuffi-cient assimilate supply due to the decline in leaf photosynthetic performance and the decrease in the ability to de-compose sucrose,and the silk of AN591 was less affected by drought stress than that of ZD909.
万方数据
维普
