photosynthesis and antioxidant activity in Ficus concinna var. subsessilis
In this study, chlorophyll fluorescence, gas exchange and antioxidant activity in Ficus concinna var. subsessilis were investigated under NaC1 stress. Under a low NaC1 concentration （50 mmol/L） treatment for 7 d, net photosynthetic rate （Pn）, stomatal conductance （Gs） and intercellular CO2 concentration （Ci） in the F. concinna var. subsessilis seedlings decreased by 24% , 31% and 30% , respectively, in comparison to the control. However, low NaC1 concentrations did not decrease the efficiency of energy conversion of open PS Ⅱ （F＇v/F＇m） and the proportion of open PSII reaction centers （qP）. These results indicated that the decline of Pn under low NaC1 concentrations was due to the stomatal factors. Under a high NaC1 concentration （200 mmol/L） treatment for 7 d, Pn, Gs, Ci, qP and F＇v/F＇m in the seedlings dropped by 81%, 54%, 51%, 72. 7% and 87.6%, respectively, compared to the control. Additionally, high NaC1 concentrations also decreased the F＇v/F＇m and qP, thereby resulting in an reduction in electron transport flow and Pn- The non-photochemical quenching （NPQ） , MDA content, SOD and POD activities of the seedlings were significantly increased after high NaC1 concentration stresses. These results showed that, though the light energy dissipation was increased, excessive excitation energy was still accumulated under high NaC1 concentrations, whictl induces the increase of activities of antioxidant enzymes and the aggravation of membrane lipid peroxidation, while the decreaseof P. under high NaC1 concentrations was due to both stomatal and non-stomatai factors.
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万方数据
维普
