芸苔素内酯对厚皮甜瓜坐果节位叶片衰老及叶绿素荧光特性的影响

Effects of brassinolide on the fruiting-node leaf senescence and characteristics of chlorophyll fluorescence in muskmelon

以厚皮甜瓜‘迎春’为试材,研究了叶面喷施不同浓度芸苔素内酯(BR)对厚皮甜瓜坐果节位叶片衰老过程中叶绿素、可溶性蛋白含量、抗氧化物酶活性及叶绿素荧光特性的影响。结果显示:1.2mmol/L的BR处理可显著延缓叶绿素和可溶性蛋白含量的下降,提高SOD和POD抗氧化酶的活性,降低MDA的含量;同时,降低了非调节性能量耗散的光化学效率[Y(NO)],提高了PSII最大光化学效率(Fv/Fm),电子传递速率(ETR),实际量子产量[Y(II)]和调节性能量耗散的光化学效率[Y(NPQ)]。研究表明,叶面喷施一定浓度的芸苔素内酯(BR)可通过提高坐果节位叶片抗氧化物酶活性延缓坐果节位叶片衰老,使之保持较高的光合特性。

The study was conducted to investigate the effects of foliage spraying of brassinolide （BR）at different concentrations on the fruiting-node leaf senescence,antioxidant enzyme activ- ity and characteristics of chlorophyll fluorescence in muskmelon. The results showed that the treatment of 1.2 mmol/L BR significantly delayed the dropping of the content of chlorophyll and soluble protein,increased the activities of antioxidative enzymes including superoxide dis- mutase（SOD） and peroxidase（POD）, and reduced the MDA content. Meanwhile, the treatment of 1.2 mmol/L BR decreased the Y（NO） and increased Fv/Fm, ETR, Y（II） and Y（NPQ）. It suggested that spraying a certain concentration BR can delay the fruiting-node leaf senescence and keep higher photosynthetic characteristics resulted from the enhancement of antioxidant enzyme activities of POD and SOD.