Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Plant Physiol Biochem. 2012 Feb;51:47-52. doi: 10.1016/j.plaphy.2011.10.015. Epub 2011 Oct 30.
Euhalophyte Salicornia europaea L., one of the most salt-tolerant plant species in the world, can tolerate more than 1000 mM NaCl. To study the salt tolerance mechanism of this plant, the effects of different NaCl concentrations on plant growth, as well as Na(+) accumulation and distribution at organ, tissue, and subcellular levels, were investigated. Optimal growth and an improved photosynthetic rate were observed with the plant treated with 200-400 mM NaCl. The Na(+) content in the shoots was considerably higher than that in the roots of S. europaea. The Na(+) in S. europaea cells may act as an effective osmotic adjuster to maintain cell turgor, promoting photosynthetic competence and plant growth. The results from the SEM-X-ray and TEM-X-ray microanalyses demonstrate that Na(+) was compartmentalized predominantly into the cell vacuoles of shoot endodermis tissues. Accordingly, the transcript amounts of SeNHX1, SeVHA-A, and SeVP1 increased significantly with increased NaCl concentration, suggesting their important roles in Na(+) sequestration into the vacuoles. Therefore, a multiple sodium compartmentalization mechanism is proposed to enhance further the salt tolerance of S. europaea.
盐沼植物盐角草（Euhalophyte Salicornia europaea L.）是世界上耐盐性最强的植物物种之一，能耐受超过 1000mM 的 NaCl。为了研究该植物的耐盐机制，本研究调查了不同 NaCl 浓度对植物生长以及器官、组织和亚细胞水平上 Na+积累和分布的影响。结果表明，用 200-400mM NaCl 处理的植物生长最佳，光合速率提高。盐角草地上部分的 Na+含量明显高于根部。盐角草细胞中的 Na+可能作为一种有效的渗透调节剂，维持细胞膨压，促进光合作用能力和植物生长。SEM-X 射线和 TEM-X 射线微分析的结果表明，Na+主要被分隔到shoot 内皮层组织的细胞液泡中。因此，随着 NaCl 浓度的增加，SeNHX1、SeVHA-A 和 SeVP1 的转录物数量显著增加，表明它们在将 Na+隔离到液泡中具有重要作用。因此，提出了一种多重钠离子分隔机制，以进一步提高盐角草的耐盐性。
