关键词: 长效油菜素内酯, 二氢茉莉酸丙酯, 大豆, 光合能力

Abstract: The effects and the action mechanisms of long lasting Brassinosteroid(TS303), Propyl dihydrojasmonate(PDJ) and their mixture on soybean photosynthetic capacity were investigated. The results showed that: (1) 0.01~1 mg·L^-1 TS303 promofed in dry matters with optimal concentration of 0.1 mg·L^-1, but had no significant effect on distribution between shoot and root. 1~100 mg·L^-1 PDJ promoted dry matter distribution to root as indicated by increasing in R/T, PDJ among 1~10 mg·L^-1 increased in dry matters with optimal concentration of 5 mg·L^-1, while an inhibitory effects occurred when applied at 50 and 100 mg·L^-1; (2)Both 0.1 mg·L^-1 TS303 and 5 mg·L^-1 PDJ promoted leaves areas, net photosynthetic rate and their derivative index photosynthetic capacity, and a synergistic effect occurred when they were applied in combination; (3)0.1 mg·L^-1 TS303 and 5 mg·L^-1 PDJ applied alone or in combination all promoted chlorophyll concentrations and PSⅡ actual efficiency (ΦPSⅡ), indicating the enhancement of light energy harvest and utilization. TS303 increased ΦPSⅡ through increasing in photochemical quenching (qP) rather than effectual PSⅡ efficiency (Fv′/Fm′) just in contrast to PDJ; (4)0.1 mg·L^-1 TS303 and 5 mg·L^-1 PDJ applied alone or in combination all increased in stomatal conductance (Gs), carbonic anhyrase activities, RuBPCase concentrations and activities, indicating the enhancement of CO₂ transportation and fixation; (5)0.1 mg·L^-1 TS303 and 5 mg·L^-1 PDJ applied alone or in combination all increased in sucrose concentrations and ratios of sucrose to starch in leaves, and increased in starch in root, indicating the amelioration to leaf carbohydrate accumulation and feedback inhibition of photosynthesis. The results suggested that it might be the differential mechanisms of TS303 and PDJ that resulted in the synergistic effect.

Key words: long-lasting brassinosteroid TS303, propyl dihydrojasmonate, soybean(Glycine max L. Merr.), photosynthetic capacity