NaCl胁迫对黄瓜幼苗体内K+、Na+和Cl-分布的影响

采用营养液水培,以2个耐盐性不同的黄瓜品种为材料,研究了不同浓度NaCl处理下幼苗植株体内K 、Na 和Cl-在器官间的区域化分布及其吸收和运输特性的变化。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浓度的升高而增大;不同器官间,茎中Na 和Cl-含量最高,上位叶中Na 和Cl-含量最低、K 含量下降幅度最小。与耐盐性较弱的“津春2号”相比,耐盐性较强的“长春密刺”根向茎运输的SK,Na值较高,根系对Na 的截留作用较强,茎向上位叶运输的SK,Na和SCl,Na值均较高,叶片中K 含量下降幅度较小,K/Na和Cl/Na比值均较高,功能叶中盐分离子尤其是Na 积累较少,植株生物量较高。说明根系对Na 的截留能力较强且向上位叶运输Na 的选择性较低,是“长春密刺”耐盐性较强的主要原因之一。

Effects of NaCl stress on K+, Na+ and Cl- allocation in different organs of Cucumis sativus L. seedlings

By the method of hydroponics,this paper studied the effects of different concentration NaCl on the allocation of K ,Na and Cl-in the seedlings of two Cucumis sativus L.cultivars with different levels of salt-tolerance.The results showed that under NaCl stress,the seedlings K content decreased,while their Na and Cl-contents increased,with the increase in salinity.Among the test organs,stem had the highest content of Na and Cl-,while upper leaves had the lowest.The decrease of K content in upper leaves was less than that in other organs.Compared with salt-susceptible cultivar 'Jinchun No.2',salt-resistant cultivar 'Changchun Mici' had a higher transportation selectivity of K to Na from root to stem,and of K to Na and Cl-to Na from stem to upper leaves,and retained more Na in root.As a result,'Changchun Mici' accumulated more K and less Na in its leaves,and the ratios of leaf K/Na and Cl/Na were higher.'Changchun Mici' also had a higher biomass than 'Jinchun No.2' under same salinity.All of these suggested that the higher accumulation of Na in roots and the lower transportation selectivity of Na from stem to upper leaves were the main reasons for the stronger salt-tolerance of 'Changchun Mici'.