NaCl胁迫下黄瓜幼苗体内K+、Na+和Cl-分布及吸收特性的研究

采用营养液水培法,研究了不同浓度NaCl胁迫对黄瓜幼苗不同器官K 、Na 和Cl-含量的影响。结果表明,NaCl胁迫下黄瓜植株体内K 含量下降,Na 和Cl-含量升高,变化幅度随NaCl浓度的增加而增大;NaCl处理4 d后,各器官中K 含量下降幅度剧增,叶片中Na 和Cl-含量快速升高;3种离子在器官间呈区域化分布,Na 主要积累在根和茎部,K 和Cl-主要积累在茎部,而且K 的含量下降幅度由根向叶递减。在低浓度NaCl胁迫或高浓度NaCl短期胁迫下,黄瓜植株对K 的吸收选择性以及向地上部运输的选择性提高,离子区域化分布的能力增强,有利于避免离子代谢紊乱,减轻NaCl胁迫的伤害。可见,离子在器官水平的区域化分布是黄瓜植株耐盐性的重要机理之一。

K+ , Na+ and Cl- Distribution and Absorption in Cucumber Seedlings under NaCl Stress

Hydroponics was adopted to study K~ ,Na~ and Cl~-contents in different parts of cucumber seedlings at different NaCl concentrations.It was shown that under NaCl stress cucumber plants decreased the K~ content and increased the Cl~-content and the decrement and increment increased as the NaCl concentrations increased;after having been treated with NaCl for four days,the K~ decrements sharply increased in various parts and the Na~ and Cl~-contents showed a quick increase in the leaves;the three ions presented a compartmentalized distribution in which Na~ mainly accumulated in the roots and stems and Cl~ mainly concentrated in the stems and K~ decrement occurred from the roots to the leaves.At high or low NaCl concentration,cucumber plants increased the selectivity of their K~ absorption and upward transport and the capacity of their compartmentalized ion distribution,which was conducive to avoiding the disorder of ion metabolism and alleviating the damage of NaCl stress.It follows that the compartmentalized ion distribution on the organ level is one of salt-tolerance mechanisms in cucumber plants.