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作 者 ：韩志平 郭世荣 郑瑞娜 束胜 闫海霞

期 刊 ：植物营养与肥料学报 2013年 19卷 4期 页码：908-917

关键词：小型西瓜；盐胁迫；离子分布；选择性运输；

Keywords:mini-watermelon, salinity, ions distribution, selective transportation,

摘 要 ：采用营养液水培法，研究了不同NaCl浓度对耐盐性不同的两个小型西瓜品种（“秀雅”和“秀丽”）幼苗体内离子分布的影响。结果表明，NaCl胁迫抑制了西瓜幼苗的生长，“秀雅”生长受抑制程度明显小于“秀丽”； 随NaCl浓度的提高，植株体内Na⁺和Cl^－含量增加，K⁺、 Ca²⁺和Mg²⁺含量降低。5种离子在器官间呈区域化分布，Cl^－主要积累在茎中而Na+主要积累于茎和根中； K⁺含量在茎中降低幅度较大，叶中降低幅度较小； Ca²⁺和Mg²⁺主要存在于茎和叶中，且在叶中降低幅度较小。NaCl胁迫下，西瓜根向茎选择性运输K⁺和Ca²⁺的能力降低，而茎向叶选择性运输的能力提高，有利于减轻NaCl胁迫对叶片的伤害。与“秀丽”相比，“秀雅”叶中K⁺、 Ca²⁺含量降低幅度较小，Cl^－和Na⁺积累量较少，K⁺/Na⁺和Ca²⁺/Na⁺比值均较高，茎向叶运输的SK，Na和SCa，Na值也较高。以上结果说明，向叶片运输Na+的选择性较低，是“秀雅”耐盐性较强的主要原因之一，离子在器官水平上的区域化分布是西瓜植株适应盐胁迫的重要生理机制之一。

Abstract:A hydroponic cultivation experiment was carried out with two miniwatermelon cultivars differing in salt tolerance to study the effect of different NaCl concentrations on ions distribution in watermelon seedlings. The results show that NaCl stress inhibits the growth of watermelon seedlings, and the extent of inhibition for ‘Xiuya’ is less than that of ‘Xiuli’. Increasing NaCl concentration, the Na⁺ and Cl^- contents of the seedlings are increased, while the K⁺, Ca²⁺ and Mg²⁺ contents decreased. The five ions present a compartmentalized distribution.  Cl^- mainly accumulates in the stems and Na⁺ mainly concentrates in roots and stems. The decreased range of the K⁺ contents is larger in stems and smaller in leaves, Ca²⁺ and Mg²⁺ mainly exist in stems and leaves and the declined extent in leaves is less. The abilities of selective transportation of K⁺ and Ca²⁺ from roots to stems are decreased, while the abilities from stems to leaves are increased under the NaCl stress, which contributes to alleviate the damage of NaCl stress to leaves. Compared to cv. ‘Xiuli’, the  K⁺ and Ca²⁺ contents in leaves of cv. ‘Xiuya’ reduced  less, Cl^- and Na⁺ accumulations are less. As a consequence,  K⁺/Na⁺ and Ca²⁺/Na⁺ radios are higher, and SK，Na and SCa，Na ratios of selective transportations from stems to leaves are also higher. This research reveals that lower selective transportation of Na⁺ to leaves is one of main reasons for cv. ‘Xiuya’ with more salttolerance, and the compartmentalized distribution of ions on the organs is one of physiological adaptation mechanisms of watermelon plants to salinity.

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