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为了研究盐胁迫下耐盐性不同的两个小白菜品种的光合生理特性, 旨在探明小白菜耐盐的光合生理机制.研究结果表明, 随着NaCl胁迫浓度的增大, 两品种小白菜的净光合速率、胞间CO2浓度以及RUBPCase均逐渐降低, 气孔限制值逐渐增大.低浓度 (0.5％) 盐胁迫对两品种小白菜光合参数均无显著影响, 1.0％NaCl胁迫下, 盐敏感品种'改良605'Pn、Ci和AMC均受到极显著抑制 (p<0.01), 1.5％NaCl胁迫下, 耐盐品种'四倍体矮脚黄'Pn均受到极显著抑制 (p<0.01), AMC受到显著抑制 (p<0.05), Ls显著提高 (p<0.05) .可见, Ls和AMC均为高浓度盐胁迫抑制小白菜光合速率的主要因素, 另外, 叶绿素合成的抑制以及荧光参数和光系统活性的抑制等也是盐胁迫引起光合速率下降的原因.“,”This paper studied the photosynthetic characteristics of two cabbage varieties with different tolerance under salt stress, aiming to ascertain the photosynthetic physiological mechanisms of Chinese cabbage under the salt stress. The results showed that with the increase of NaCl concentration, the net photosynthetic rate, intercellular CO2 concentration and the RUBPCase of two varieties of cabbage decreased gradually, and the stomatal limitation value increased gradually. Low NaCl concentration (0. 5％) stress showed no significant effect on the photosynthetic parameters of two cabbage varieties. The Pn, Ci and AMC of salt-sensitive variety 'improvement605' were significantly inhibited (p<0. 01) under 1. 0％ NaCl stress. Pn of tolerant variety 'tetraploid Aijiaohuang' was significantly inhibited (p<0. 01), AMC was significantly inhibited (p<0. 05) and Ls was significantly promoted (p<0. 05) under 1. 5％ NaCl stress. It could clearly be seen that Ls and AMC were the main factors affecting the photosynthetic rate of cabbage under high concentration of salt stress. In addition, inhibition of the chlorophyll fluorescence parameters and synthesis and the activity of the optical system were also the major factors leading to the photosynthetic rate decline caused by salt stress.