盐胁迫对二穗短柄草幼苗生长及不同器官中盐离子稳态的影响

采用4种浓度的NaCl溶液(50、100、150、200 mmol/L)处理二穗短柄草和拟南芥(对照)幼苗,测定不同浓度盐胁迫下2种植物幼苗的生长指标和离子分布,以探讨二穗短柄草在盐胁迫下主要阳离子平衡机制.结果表明:(1)盐胁迫显著抑制二穗短柄草根叶的生物量积累.(2)根冠比数据显示,在盐胁迫条件下二穗短柄草能够更好地维系地下部分的生物量积累.(3)在4种浓度盐胁迫下,二穗短柄草叶中Na+含量低于根系,而且K+、Cl-含量和K+/Na+比值始终高于根系,说明在二穗短柄草中Na+从地下到地上的转运受到抑制,但对Cl-的转运缺乏有效的调控.(4)回归分析发现,盐胁迫下二穗短柄草和拟南芥根部Na+与K+含量变化呈正相关关系,而在叶部则不相关,说明二穗短柄草和拟南芥Na+与K+在根部具有相同的离子通道,而在叶部却具有各自独立的转运途径.

Brachypodium distachyon Seedling Growth and Ionic Homeostasis in Its different Organs under Salt Stress

To investigate the effect of salt stress on growth and ion distribution of Brachypodium distachyon (Bd21),we treated Bd21 seedlings with various concentration of NaCl,while the Arabidopsis thaliana seedlings were used as control.The results showed that:(1)The growth of roots and leaves of Bd21 was markedly inhibited under salt treatments.(2)Based on the results of root/leaf ratio,root growth of the Bd21 was better than that of Arabidopsis seedlings under the same salt treatments,suggesting that Bd21 is more tolerant to salt stress compared to the Arabidopsis seedlings.(3)Leaf Na⁺ content was lower than that in roots,and the K⁺,Cl^-,and the ratio of K⁺/Na⁺ in leaves were higher than those in roots under salt treatments,indicating that the transport of Na⁺ from the root to the shoot is effectively inhibited in Bd21.(4)Positive correlations of Na⁺ and K⁺ content were found in Bd21 and Arabidopsis roots,however,no correlations were found in leaves.These results implied that the same transporters are used to transport the Na⁺ and K⁺ in both plant roots and different channels are needed in leaves.