| Four concentrations of natural brassinolid were used for foliage spray to investigate their physiological effects on Fuji apple in hilly regions on the Loess Plateau. The changes of chlorophyll content, carotenoid content, proline content, malondialdehyde (MDA) content, superoxide dismasted (SOD), peroxides activity (POD) and yield were measured. The results showed that under different concentrations of natural brassinolide, MDA content was decreased dramatically, while SOD and POD activity, chlorophyll content, carotenoid content and proline content were increased significantly. The concentration of 0.2 mg/L was the best for increasing fruit yield of apple trees. |