Figure 1a shows that the net photosynthetic rate varies with the time of zinc treatment and zinc concentration. Compared with the control group, the net photosynthetic rate of the treatment group with zinc concentration less than 800 μmol/L was significantly higher than that of the control group. When the zinc concentration was less than 400 μmol/L, the net photosynthetic rate increased slowly with the prolongation of zinc treatment time, but there was no significant difference between different treatment days. At the same time, when the zinc concentration is less than 400, the net photosynthetic rate increases with the increase of zinc concentration. When the zinc concentration was 400 μmol/L, it reached the maximum value, and there was significant difference compared with the control group.

Figure 1b shows that the transpiration rate varies with the time of zinc treatment and zinc concentration. Compared with the control group, the transpiration rate of all treatment groups with zinc concentration less than 400 μmol/L was significantly higher than that of the control group, and increased significantly with the increase of zinc concentration. At the same time, we found that when the zinc concentration was between 200 μmol/L and 400 μmol/L, the transpiration rate increased significantly with the increase of zinc treatment time. However, when the concentration of zinc was more than 400 μmol/L, the transpiration rate decreased significantly with the increase of zinc concentration. When the zinc concentration was 400 μmol/L and the treatment time was 21 days, the transpiration rate reached the maximum value, and there was significant difference compared with the control group.