Abstract: Jasmonic acid (JA) were sprayed on the leaves of Hevea brasiliensis, and the photosynthetic capacities, photosynthetic pigments, and antioxidant metabolites as well as activities of antioxidant enzymes after treated by JA for 1, 24, 48, 72, 96, 120 h were measured. The results revealed that JA led to the decline in maximum net photosynthetic rate, stomata conductance, and photochemical efficiency of photosystem II. The decline in photosynthetic capacity might be resulted from the JA-induced decreases in the contents of chlorophyll, carotenoids, and total soluble protein. Whereas, the levels of hydrogen peroxide (H₂O₂) were increased after JA treatment. Meanwhile, the increases in H₂O₂ levels could activate the antioxidant system. Therefore, the activities of superoxide dismutase, catalase, and guaiacol peroxidase were increased, and the cycles of ascrobate-glutathione were enhanced after the JA-induced increase in H₂O₂ levels. However, the potential antioxidants of α-pinene, β-pinene, sabinene, and total monoterpene were initially increased, and then decreased.

Key words: Hevea brasiliensis, jasmonic acid (JA), photosynthesis, antioxidant system, monoterpene