盐胁迫下小麦幼苗离子吸收运输的选择性与叶片耐盐量

STUDIES ON K^+,Na^+ SELECTIVITY DURING ION UPTAKE AND TRANSPORT AND SALT TOLERANCE OF LEAF CELLS OF WHEAT SEEDLINGS UNDER SALT STRESS CONDITIONS

研究了小麦品种 LD-1(耐盐)和扬麦5号(不耐盐),在盐胁迫下植株体内 K^+、Na^+积累及其吸收、运输过程中的选择性和叶片电解质渗漏率的变化.结果表明,盐胁迫后 LD-1叶片〔Na^+〕/〔K^+〕明显低于扬麦5号,而其 S_(k,Na)(K^+,Na^+选择性比率)显著大于扬麦5号.2品种间根系〔Na^+〕/〔K^+〕及 S_k,Na均没有显著差异,根系离子吸收的选择性相似.LD-1从根系至地上部的离子运输过程中,具有较大的 K^+选择性,是它具有较强耐盐性的主要原因.2品种间叶片耐盐阈值及叶片致死盐量均无显著差异,叶片细胞的耐盐力相似.

Changes in K^+,Na^+ content in plants,K^+,Na^+ selectivity during ion uptake and transport,percentage electrolyte leakage in leaves in two wheat(T.aestivum)varieties,i.e.LD-1(salt-tolerant)andYangmai No.5(salt-sensitive)under saline conditions were studied.Results showed that ratio of〔Na^+〕/(K^+)in leaves of LD-1 was much lower than that of Yangmai No.5,while S_(κ,Na)for the leaf of the for-mer was much higher than that of the latter.The ratio of〔Na^+〕/〔K^+〕and S^(k,Na)for the root of the twovarieties was almost the same demonstrating similar K^+-Na^+ selectivity during ion uptake.It is suggestedthat salt tolerance in salt-tolerant variety is mainly due to its higher selectivity for K^+ relative to Na^+ duringtransport to the shoot.Salt tolerance of leaf cells of the two varieties was similar because of the same saltthreshold and lethal salt content of leaf cells.