亚适宜温光盐环境下油菜素内酯对黄瓜幼苗抗氧化系统及光合作用的影响

研究了24 表油菜素内酯(EBR)对亚适宜温光盐环境下黄瓜幼苗抗氧化系统及光合作用的影响.结果表明: 与对照相比,亚适宜温光盐环境下黄瓜幼苗叶片H₂O₂含量增加,膜脂过氧化程度加剧,膜透性增强,净光合速率(P_n)、气孔导度(g_s)、胞间CO₂浓度(C_i)和蒸腾速率(T_r)分别显著下降39.3%、40.0%、21.2%和47.2%,幼苗干物质积累减少35.9%.外源喷施EBR可提高亚适宜温光盐环境下黄瓜幼苗的抗氧化酶活性,降低H₂O₂含量及膜透性,缓解亚适宜温光盐环境下P_n、g_s、T_r的下降幅度,幼苗干物质积累增加25.9%,生长加快．EBR可通过调节亚适宜温光盐环境下黄瓜幼苗抗氧化性,减少其膜脂过氧化程度,进而维持其较高的光合性能,有效促进了亚适宜温光盐环境下黄瓜幼苗的生长．

Effects of brassinolide on the antioxidant system and photosynthesis of cucumber seedlings under suboptimal temperature,light and salt environment.

The effects of 24 epibrassinolide (EBR) on antioxidant system and photosynthesis of cucumber seedlings were studied under suboptimal temperature, light and salt environment. Compared with the control, the leaf H₂O₂ content, lipid peroxidation and cell membrane permeability significantly increased, and the leaf net photosynthetic rate (P_n), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), transpiration rate (T_r) and dry matter accumulation decreased by 39.3%, 40.0%, 21.2%, 47.2% and 35.9% in the suboptimal environment, respectively. Applying EBR could further improve the antioxidant enzyme activity, reduce the H₂O₂ content and membrane permeability of seedlings, alleviate the drop range of P_n, g_s and T_r, improve the growth of seedlings and increase the dry matter accumulation by 25.9%. Therefore, EBR treatment could keep higher photosynthetic performance to effectively promote cucumber seedlings growth through adjusting the protective enzyme activity and reducing membrane lipid peroxide level under suboptimal temperature, light and salt environment.