鱼腥藻7120响应NaCl胁迫的光合特性

NaCl胁迫处理丝状蓝藻鱼腥藻7120后光合特性的变化表明；鱼腥藻7120的净光合放氧速率和呼吸速率随NaCl浓度的程式高而降低，且浓度低于0.4mol/LNaCl时的降幅比高于0.4mol/LNaCl时的降幅小，加入0.4%(W?V)的蔗糖后可提高盐胁迫后的鱼腥藻7120的光合放氧速率，吸收光谱测定结果表明盐胁迫没有改变鱼腥藻7120的光合色素组成，但导致藻胆蛋白的总含量降低，类胡萝卜素含量增加。低温荧光发射光谱测定表明盐胁迫后改变了光能在两个光系统之间的分配。由藻胆蛋白吸收的光能向光Ⅱ传递受阻。荧光动力学分析表明光系统Ⅱ的光化学效率随盐浓度的增加而降低。表现出与光合放氧速率的一致性。

CHANGES IN PHOTOSYNTHETIC PROPERTIES OF A FILAMENTOUS CYANOBACTERIUM ANABAENA SP.PCC 7120 IN RESPONSE TO NaCl STRESS

The changes in photosynthetic properties of filamentous cyanobacterium Anabaena sp.PCC 7120(A. 7120) in response to NaCl stress had been studied.It showed that both the net photosynthetic oxygen evolution rates and respiration rates were decreased more quickly with increasing NaCl concentrations when NaCl concentrations exceed 0.4 mol/L were. The absorption spectra had been shown that the photosynthetic pigments of A. 7120 under NaCl stress were unchanged,but the total contents of phycobiliproteins decreased and those of carotenoids increased.The low temperature fluoresence emission spectra suggested that the energy transfer from phycobiliprotein to photosystem I in A.7120 under NaCl stress was depressed.And the chlorophyll a fluoresence induction kinetics analysis displayed that changes in Fv/Fm ratios of A.7120 was consistent with those of the net photosynthetic oxygen evolution rates in response to NaCl stress.