Effect of H2S and rhizobia on antioxidant enzyme system in soybean plant leaves under water deficiency
As shown in Fig. 6A, with the decrease of water content, the SOD activity showed a trend of increased first and then decreased by control and NaHS treatments, and the SOD activity was decreased in varying degrees by Q8 and Q8+NaHS treatments (Fig. 6A). Under the three water conditions, the POD activity was sharply increased by Q8 and Q8+NaHS treatments. With the decrease of water content, the POD activity was no apparent changed under control treatment, but NaHS treatment showed a trend of increasing first and then decreasing. Moreover, the POD activity was obviously inhibited by Q8+NaHS treatments under MW and SW conditions (Fig. 6B). The CAT activity was substantially enhanced by four treatments under SW condition compared with NW condition. In contrast, the CAT activity was increased by 5.0 and by 5.3-fold under the Q8 and Q8+NaSH treatments compared with control under SW condition, respectively (Fig. 6C). In addition, with the decrease of water content, the APX activity was notably enhanced by control and Q8+NaHS treatments. However, the APX activity of NaHS and Q8 treatments displayed a tendency to decrease initially and then increase, and no matter what the water content, the APX activity by Q8+NaHS treatment was higher than control (Fig. 6D).