afternoon change
2.It is found that the WUE of both varieties is higher in the morning, with a peak at 8～10 am than in the afternoon. The change of WUE is determined by non symmetry and contrary characteristics of Pn and Tr, i.e.,Pn is higher in the morning than in the afternoon, but Tr is on the contrary. The Pn and Tr values are all lower under water stress condition, but the WUE of different varieties is not the same.
4.5. CO_2 fertilizer after processing, compares with Elizabeth, Lanfeng has a bigger change, morning the peak value increase had the large scale increase along with the CO_2 concentration increase, the peak value treatment Ⅰ (700μL·L~(-1)) , treatment Ⅱ (1100μL·L~(-1)) separately to increase 39.6% compared to the comparison 46.5%, afternoon the peak value increased are not many;
