NaCl胁迫对黄瓜幼苗植株生长和光合特性的影响

采用营养液水培法,选用耐盐性不同的2个黄瓜品种,研究了不同浓度N aC l处理对黄瓜幼苗植株生长及叶片光合特性的影响。结果表明,在盐胁迫下,净光合速率(Pn)呈下降趋势,气孔导度(G s)变化趋势与Pn相一致;气孔限制值(L s)在处理的前4 d显著升高,随处理时间延长而下降;细胞间隙CO2浓度(C i)的变化趋势与L s相反;光合碳同化的量子效率(Φc)明显下降。耐盐性较弱的‘津春2号’各项光合参数变化幅度明显大于耐盐性较强的‘长春密刺’。短期N aC l处理,Pn下降以气孔限制因素为主,较长期N aC l处理,Pn下降转向非气孔限制因素。

Effects of NaCl Stress on Growth and Photosynthetic Characteristics of Cucumber (Cucumber sativus L. ) Seedlings

Two cucumber varieties with different salt resistances were hydroponically cultured to study the effects of NaCl at different concentrations on the growth and leaf photosynthetic characters of cucumber seedlings.The results indicated that under salt stress,the net photosynthetic rates tended to decline and the stomatal conductance appeared to vary in the same manner as the net photosynthetic rates;the stomatal limitation values remarkably increased in the first four treatment days and then declined with the treatment duration prolonged;the intercellular CO_2 concentrations and the stomatal limitation values presented opposite tendencies and the apparent quantum yields in photosynthetic carbon assimilation remarkably declined.'Jinchun 2' with weaker salt resistance varied in its various photosynthetic parameters more greatly than 'Changchun Mici' with stronger salt resistance.In the short-period NaCl treatment the decrease in Pn mainly resulted from the stomatal limitation and in the long-period NaCl treatment the situation changed in which the decrease in Pn was the result of non-stomatl limitation.