盐胁迫下野大麦耐盐生理机制初探

Primary Studies on Physiological Mechanisms of Salt Tolerance in Hordeum brevisubulatum under Salt Stress

以盐生植物野大麦、甜土植物中国春小麦为材料,研究了NaCl胁迫对野大麦、小麦幼苗叶片质膜透性、含水量、地上和根部离子含量、脯氨酸含量、磷酸烯醇式丙酮酸羧化酶(PEPCase)活性的影响。结果表明,随盐胁迫浓度增加,野大麦的细胞膜透性、Na+含量、脯氨酸含量、Na+/K+、PEPCase活性增加,含水量、K+含量下降;但在相同盐胁迫条件下野大麦地上部和根部Na+含量明显低于小麦,而根中K+含量高于小麦,表明野大麦可能具有拒绝吸收Na+和维持高K+含量的能力;野大麦的脯氨酸含量增加幅度小于小麦,表明在盐胁迫下野大麦不是通过脯氨酸的积累来达到体内渗透平衡的;野大麦PEPCase活性增加明显高于小麦,说明提高光合效率可能是野大麦实现盐适应的主要措施之一。

The effect of NaCl stress on ion and water content, membrane permeability, change of proline content and activity of PEPCase were studied in Hordeum brevisubulatum （shortsubulate barley） and Triticum aestivum cv. Chinese spring. The result showed that, membrane permeab creased as NaCl concentration was increased, while ility, contents of Na^＋ contents of water and and proline, Na^＋/K^＋ , K^＋ decreased ; under the PEPCase activity insame saline condition Na^＋ contents in shoots and roots of shortsubulate barley were less than those of wheat, and K^＋ content in roots of shortsubulate barley was more than that of wheat. These indicated that shortsubulate barley tended to take up less Na^＋ and maintain higher K^＋ in shoots. The increment of proline in shortsubulate barley was less than that in wheat, which showed that osmotic homeostasis in shortsubulate barley was not realized by excess increment of proline under salt stress ; and the fact that the activity of PEPCase in shortsubulate barley was higher than that in wheat indicated that the improvement of photosynthetic efficiency is possibly one of the main ways for shortsubulate barley to adapt to salt stress.