摘要
75和150 mmol/L NaCl处理.降低棉花幼苗叶面积、叶相对扩展率,蒸腾和木质部汁液K^+浓度;而增大叶细胞质膜透性、渗透势、叶Na^+含量和木质部汁液Na^+和Cl^-的浓度。生长在75mmol/L NaCl加压(根际)和不加压条件下的棉花,叶面积、叶相对扩展率、蒸腾、叶质膜透性和渗透势的变化基本一样。这些结果表明棉花幼苗的拒盐能力不大,盐害的原因是盐的原初效应,而不是盐的次生效应。另外,盐对棉花幼苗叶相对扩展率和质膜透性的效应在生长后期降低,表明棉花幼苗也具有一定的耐盐能力。
Cotton seedlings were cultured in 75 and 150mmol/L NaCl without pressure and in 75 mmol/LNaCl with pressure (root zone). The leafarea, relative leaf expansion rate, transpiration,permeability of plasma membrane and osmoticpotential in leaves, Na^+ content in leaves andconcentration of Na^+, K^+, Cl^- and SO_4^- in xylemsap were determined. The results show thatwhen seedlings are cultured in 75 and 150 mmol/LNaCl, the leaf area, relative leaf expansionrate, transpiration and K^+ concentration in xylemsap are remarkably decreased, but the permea-bility of plasma membrane and osmotic potentialin leaves, Na^+ content in leaves and concentra-tions of Na^+, Cl^- in xylem sap are increased.SO_4^(2-) concentration changes slightly. The chan-ges of leaf area, relative leaf expansion rate, trans-piration and osmotic potential in leaves of cottonseedlings Cultured in 75 mmol/L NaCl with pres-sure are about the same as those cultured in theidentical amount of NaCl without pressure. Theabove results show that the ability of cottonseedlings to salt-exclusion is low the Salt injuryis due to the primary effect of salt (ion stress),not to its secondary effect (water stress). More-over, the effects of salt on relative leaf expan-sion rate and permeability of plasma membranesignificantly decreased at the late growth stage.This shows that cotton seedling have a certainability to salt-tolerance.
关键词
棉花
氯化钠
质膜透性
cotton
leaf area
relative leaf expansion rate
permeability of plasma membrane
osmotic potential
transpiration
salt ions
