KCl和NaCl处理对盐生植物碱蓬幼苗生长和水分代谢的影响

研究了用不同浓度KCl和等浓度NaCl处理的盐生植物碱蓬幼苗水分代谢的变化.结果表明,NaCl处理显著促进碱蓬生长,根吸水增加,含水量高于对照.而相同浓度KCl处理却严重抑制碱蓬生长,含水量显著下降,400 mmol/L的 KCl处理后6 d,地上部分发生萎蔫,尔后死亡.KCl处理伤害碱蓬的原因之一是抑制根系吸水,而对蒸腾速率无显著影响,即水分吸收速率与蒸腾速率比值下降,植株缺水引起伤害.

Effects of KCl and NaCl Treatment on Growth and Water Metabolism of Halophyte Suaeda salsa Seedlings

Salt-dilution halophyte Suaeda salsa seedlings were treated with different concentration of KCl and isotonic NaCl. The results showed that NaCl treatment significantly enhanced growth of the Shoots (Figs.1 and 2). While growth of the shoots were markedly decreased when the plants were treated with isotonic KCl (Figs.1 and 2). The plants treated with 400 mmol/L KCl wilted and died after 6 days. The water content increased with 50 and 100 mmol/L NaCl treatment, and the relative water content had no significant changes in a range of 0-200 mmol/L NaCl (Fig.3). The water content and the relative water content declined with increase of KCl concentration (Fig.3). Water uptake rate of the plants treated with 200 mmol/L NaCl increased significantly and transpiration rate had no significant changes (Fig.5), so the ratio of water uptake rate over transpiration rate increased compared with those of controls. While the plants were treated with isotonic KCl, water uptake rate decreased significantly and transpiration rate was not affected obviously (Fig.5), i.e., the ratio of water uptake rate over transpiration rate decreased. The results suggest that one of reasons for KCl toxicity is that water uptake of the roots was interrupted by KCl treatment leading to plant damage due to the imbalance of water metabolism.