等渗NaCl和KCl胁迫对高粱幼苗生长和气体交换的影响

本文比较研究了等渗ＮａＣｌ和ＫＣｌ胁迫下，高粱幼苗生长及叶片离子含量、质膜相对透性和有关气体交换参数的变化。结果表明，在低浓度ＮａＣｌ和ＫＣｌ胁迫７天时，高粱生长、含水量和质膜相对透性与对照相比没有明显变化，而净光合速率、蒸腾速率和气孔导度已明显下降，叶肉细胞间隙ＣＯ２浓度明显增加。ＮａＣｌ胁迫下叶片Ｎａ＋含量成倍增加，而Ｋ＋和Ｃａ２＋含量无明显变化。ＫＣｌ胁迫时叶片Ｋ＋含量明显增加，Ｃａ２＋含量明显下降，而Ｎａ＋含量没有明显变化。随着ＮａＣｌ或ＫＣｌ浓度的增加，幼苗生长和叶片含水量明显下降，质膜透性和细胞间隙ＣＯ２浓度明显增加，净光合速率、蒸腾速率和气孔导度进一步下降。ＮａＣｌ胁迫下叶片Ｎａ＋含量进一步增加，Ｋ＋和Ｃａ２＋进一步下降，而ＫＣｌ胁迫下叶片Ｋ＋含量进一步增加，Ｎａ＋和Ｃａ２＋含量进一步下降。ＫＣｌ对高粱生长抑制、质膜透性、Ｃａ２＋含量下降及光合气体交换参数的影响均明显大于等渗的ＮａＣｌ。

Effects of Iso_osmotic NaCl and KCl Stress on Growth and Gas Exchange of Sorghum Seedlings

The growth of sorghum seedings,ion contents,relative plasmalemma permeability and gas exchange of the leaves under iso osmotic NaCl and KCl stress were studied.The results indicate that under the stress of low concentrations of NaCl and KCl for 7 days, the growth of the seedings,water content and relative plasmalemma permeability of the leaves were not significantly affected compared to control plants.But the net phytosynthetic rate, transpiration rate and stomatal conductance were markedly decreased and the intercellular CO 2 concentration was markedly increased.Correspondingly, the Na content in the leaves increased many times under NaCl stress,but K and Ca 2 contents were not obviously altered. The K content significantly increased and the Ca 2 content significantly decreased under KCl stress,but the Na content was not affected. With the increase of NaCl or KCl concentration,the growth of the seedings and the leaf water content markedly decreased,but relative plasmalemma permeability and intercellualar CO 2 concentration significantly increased,and the net photosynthetic rate,transpiration rate and stomatal conductance further decreased. The Na content in the leaves further increased, and the K and Ca 2 contents in the leaves decreased with the increase of NaCl concentration. Similarly, the K content in the leaves further increased,and the Na and Ca 2 contents further decreased with the increase of KCl concentration. KCl had much more detrimental effects on the growth,plasmalemma permeability,Ca 2 metabolism and photosynthetic gas exchange of the sorghum seedings than iso osmotic NaCl.