NaCl胁迫下棉花体内 Na~+ 、K~+分布与耐盐性

采用盐化土壤方法 ,选择苗期耐盐性较强的陆地棉品种枝棉 3号和中棉所 1 9及耐盐性较弱的品种泗棉 2号和苏棉 1 2号 ,研究了盐胁迫下棉苗体内 Na+、K+的运输和分配与耐盐性的关系。结果表明 ,耐盐品种根系具有一定的截留 Na+作用。棉花地上部盐分器官水平上的区域化分布特征明显 :2 0 0 mmol/L Na Cl胁迫下 ,枝棉 3号叶片中的 Na+含量显著低于泗棉 2号 ,茎及叶柄中的 Na+含量显著高于泗棉 2号 ;棉株地上部茎、叶柄、叶片中的 Na+含量分别由下而上逐渐减小 ,相同节位的茎、叶柄中的 Na+含量大于叶片 ,枝棉 3号更显著。1 0 0 mmol/L和 1 50 mmol/L Na Cl胁迫下 ,枝棉 3号和中棉所 1 9K+/Na+显著高于泗棉 2号和苏棉 1 2号。Na+在茎和叶柄中滞留和积累 ,根中的 K+向地上部选择性运输 ,以维持叶片中较高的 K+/Na+,是棉花耐盐性的一个重要特点

Distribution of Na~+ and K~+ in cotton plant under NaCl stress and salt tolerance

Ion(Na +,K +) accumulation and distribution within whole plant of cotton ( Gossypium hirsutum L.) seedlings under the stress of 100 mmol/L,150 mmol/L or \{200 mmol/L NaCl\} in the soil were studied by 3 experiments with selected cvs.Zhimian 3 and Zhongmiansuo 19 (salt tolerant),Simian 2 and Sumian 12 (salt sensitive).The results showed that,the roots of salt tolerant cvs.played a role as pool areas of Na +.The salt tolerant cvs.had the significantly higher ability of selective transportation K + from roots to shoots (S\-\{K +,Na +\}) than salt sensitive cvs.under NaCl stress.There was a regular confined distribution of Na + in shoots of cotton under NaCl stress:contents of Na + in stems,petioles,and laminas of the whole plant programmed a de escalation from down to upper;and in the same node,Na + contents in stems and petioles were higher than that in lamina;the salt tolerant cvs behaved it more certainly.Contents of K + and K +/Na + ratio in shoots of salt tolerant cvs.were higher than that of salt sensitive cvs.It was a major characteristic of mechanism of salt tolerance in cotton that the confined distribution areas of Na + in shoots maintained a homeostasis of Na +,K + with the higher K +/Na + by selective transportation K + from roots to shoots,and interception Na + in stems and petioles.