NaCl胁迫对醋栗番茄、樱桃番茄和番茄幼苗生长、叶片气体交换和离子平衡的影响

以醋栗番茄( Solanum pimpinellifolium Linn.)、樱桃番茄品种‘秦皇贵妃红’( S. lycopersicum var. cerasiforme‘Qinhuangguifeihong’)和番茄品种‘浙粉202’(S. lycopersicum‘Zhefen 202’)幼苗为材料，研究了0(对照)、100、200 mmol·L-1 NaCl胁迫对其生长、叶片气体交换参数和离子平衡的影响。结果表明：在100和200 mmol·L-1 NaCl胁迫下，‘秦皇贵妃红’和‘浙粉202’幼苗单株总干质量的降幅较大，醋栗番茄的降幅较小。 NaCl胁迫明显增加醋栗番茄幼苗的根冠比，但不同胁迫条件下‘秦皇贵妃红’和‘浙粉202’幼苗的根冠比差异不显著。与对照相比，在100 mmol·L-1 NaCl胁迫下，醋栗番茄幼苗叶片的净光合速率( Pn)、胞间CO2浓度( Ci)和蒸腾速率( Tr)的降幅明显低于‘秦皇贵妃红’和‘浙粉202’，而醋栗番茄幼苗叶片气孔导度(Gs)的降幅明显高于后二者；在200 mmol·L-1 NaCl胁迫下，三者叶片Pn、Gs、Ci和Tr值的降幅接近。在100和200 mmol·L-1 NaCl胁迫下，醋栗番茄、‘秦皇贵妃红’和‘浙粉202’幼苗叶片的水分利用效率和气孔限制值均较各自对照显著升高，其中‘秦皇贵妃红’的增幅最大。在100和200 mmol·L-1 NaCl胁迫下，醋栗番茄、‘秦皇贵妃红’和‘浙粉202’幼苗根、茎和叶中Na+含量均较各自对照显著升高，而K+含量和K+/Na+比总体上较各自对照显著降低。与对照相比，经不同浓度NaCl处理后醋栗番茄幼苗根、茎和叶的Na+含量增幅以及K+含量降幅在供试3种植物中均最小，而其不同部位的K+/ Na+比总体上较高。上述研究结果表明：醋栗番茄的耐盐性较强，‘秦皇贵妃红’次之，‘浙粉202’较弱。 NaCl胁迫显著抑制‘秦皇贵妃红’和‘浙粉202’幼苗根的生长，但显著促进醋栗番茄幼苗根的生长，使其维持较强的耐盐性，且NaCl胁迫下醋栗番茄对Na+的吸收和运输减少，以维持体内的离子平衡及较强的光合作用。

Effect of NaCl stress on growth,leaf gas exchange and ion balance of seedlings of Solanum pimpinellifolium,S. lycopersicum var. cerasiforme and S. lycopersicum

Taking seedlings of Solanum pimpinellifolium Linn., S. lycopersicum var. cerasiforme‘Qinhuangguifeihong’ and S. lycopersicum ‘Zhefen 202’ as materials, effect of 0 (the control), 100 and 200 mmol · L-1 NaCl stresses on their growth, leaf gas exchange parameters and ion balance was studied. The results show that under 100 and 200 mmol·L-1 NaCl stresses, decreasing range of total dry weight per plant of ‘Qinhuangguifeihong ’ and ‘Zhefen 202 ’ seedlings is bigger, and that of S. pimpinellifolium is smaller. NaCl stress can obviously enhance root/shoot ratio of S. pimpinellifolium seedling, but difference in root/shoot ratio of ‘Qinhuangguifeihong’ and ‘Zhefen 202’ seedlings is not significant under different stresses. Compared with the control, under 100 mmol · L-1 NaCl stress, decreasing ranges of net photosynthetic rate ( Pn) , intercellular CO2 concentration ( Ci) and transpiration rate ( Tr) of leaf of S. pimpinellifolium seedling are obviously lower than those of ‘Qinhuangguifeihong’ and ‘Zhefen 202’, while that of stomatal conductance (Gs) of leaf of S. pimpinellifolium seedling is obviously higher than that of the latter two. Under 200 mmol·L-1 NaCl stress, decreasing ranges of Pn, Gs, Ci and Tr values of leaves of S. pimpinellifolium, ‘Qinhuangguifeihong ’ and ‘Zhefen 202 ’ are close. Under 100 and 200 mmol·L-1 NaCl stresses, water use efficiency and stomatal limitation value of leaves of S. pimpinellifolium,‘Qinhuangguifeihong’ and‘Zhefen 202’ seedlings are significantly higher than those of their respective control, in which, increasing range of‘Qinhuangguifeihong’ is the biggest. Under 100 and 200 mmol·L-1 NaCl stresses, Na+content in root, stem and leaf of S. pimpinellifolium,‘Qinhuangguifeihong’ and ‘Zhefen 202’ seedlings increases significantly than those of their respective control, while K+ content and K+/Na+ ratio totally decrease significantly than those of their respective control. Compared with the control, after treated by different concentrations of NaCl, increasing range of Na+ content and decreasing range of K+content in root, stem and leaf of S. pimpinellifolium seedling are all the lowest in three plants tested, while, its K+/ Na+ ratio in different parts is higher generally. It is suggested that salt tolerance of S. pimpinellifolium is stronger, that of ‘Qinhuangguifeihong ’ is the second, and that of ‘Zhefen 202 ’ is weaker. NaCl stress can significantly inhibit root growth of‘Qinhuangguifeihong ’ and ‘Zhefen 202 ’ seedlings, while it can significantly promote that of S. pimpinellifolium to maintain stronger salt tolerance. Under NaCl stress, Na+ uptake and transport of S. pimpinellifolium decrease for maintaining ion balance and stronger photosynthesis.