植物耐盐性是一种生理上复杂的性状,有许多机制促成。在这项工作中,我们表明,叶肉保留K()的能力代表了盐度耐受机制的重要且基本上被忽视的组成部分。在筛选46种大麦(HordeumvulgareL.)基因型时,发现了盐分条件下的叶肉K()保留能力(通过NaCl诱导的叶肉中K()流出的幅度量化)与总体耐盐性(相对鲜重和/或盐度胁迫下的存活率或损害)之间存在强正相关。发现在控制条件下具有固有较高的叶片K()含量的基因型在盐度下具有更好的K()保留能力,因此,总体耐受性较高。与以前关于大麦根的报道相反,叶肉中的K()保留与耐性品种的H()抽水增加无关,而是与该性状负相关。这些发现可以通过以下事实来解释:可能需要增加的H()挤出来平衡活性,并为恢复盐敏感的细胞溶质K()稳态所需的高亲和力HAK/KUPK()转运蛋白提供驱动力基因型。
Plant salinity tolerance is a physiologically complex trait, with numerous mechanisms contributing to it. In this work, we show that the ability of leaf mesophyll to retain K(+) represents an important and essentially overlooked component of a salinity tolerance mechanism. The strong positive correlation between mesophyll K(+) retention ability under saline conditions (quantified by the magnitude of NaCl-induced K(+) efflux from mesophyll) and the overall salinity tolerance (relative fresh weight and/or survival or damage under salinity stress) was found while screening 46 barley (Hordeum vulgare L.) genotypes contrasting in their salinity tolerance. Genotypes with intrinsically higher leaf K(+) content under control conditions were found to possess better K(+) retention ability under salinity and, hence, overall higher tolerance. Contrary to previous
reports for barley roots, K(+) retention in mesophyll was not associated with an increased H(+) -pumping in tolerant varieties but instead correlated negatively with this trait. These findings are explained by the fact that increased H(+) extrusion may be needed to charge balance the activity and provide the driving force for the high affinity HAK/KUP K(+) transporters required to restore cytosolic K(+) homeostasis in salt-sensitive genotypes.