缺磷胁迫加重柑橘叶片光合作用的光抑制及叶黄素循环的作用

用营养液培养的方法 ,研究了不同光强和磷水平对温州蜜柑叶片光合作用光抑制的影响。结果表明 ,在缺磷强光条件下 ,叶片的初始荧光Fo、最大荧光Fm、PSⅡ光化学效率 (Fv/Fm)及表观电子传递速率 (ETR)下降 ,叶片非光化学猝灭的慢相 (qNs)和叶温升高。用叶黄素循环的抑制剂DTT处理叶片后 ,Fo升高。这些结果说明 ,缺磷胁迫加重了温州蜜柑叶片光合作用的光抑制 ,叶黄素循环的非辐射能量耗散在保护光合机构免受强光破坏方面起着重要作用。

Phosphorus deficiency stress aggravate photoinhibition of photosynthesis and function of xanthophyll cycle in citrus leaves

Effects of different light intensities and phosphate levels on photoinhibition of photosynthesis in satsuma mandarin(Citrus unshiu Marc.) leaves were studied in the culture solution. The results showed that under high light intensity and the condition of phosphate deficiency, initial fluorescence(Fo), maximal fluorescence(Fm), photochemical efficiency of PSII(Fv/Fm)and apparent electron transport rate (ETR) decrease, on the other hand, slow -phase (qN_s) of non-photochemical quenching and leaf temperature increase. After treated by DTT, Fo was much higher than control(H₂O). These results indicated that phosphorus deficiency stress aggravate photoinhibition of photosynthesis, xanthophyll cycle-dependent non-radiate energy heat dissipation played an important protective role against photo-damage to the photosynthetic apparatus in satsuma mandarin leaves during phosphate deficiency stress.