全世界超过20%的农业用地受到盐渍化的威胁，但一些植物能够在高盐环境下生活，被称为盐生植物。了解盐生植物的耐盐机制对于培育耐盐作物和牧草品种具有重要意义。日前，中科院东北地理所揭示盐生植物早期生长阶段耐盐机制，相关成果发布于《植物与土壤》。

以往研究植物的耐盐机制大多使用单盐，通常是氯化钠，事实上盐渍化土壤中包含各种阴阳离子。此外，前人研究多关注一个物种或几个物种，缺少不同盐生植物间的对比研究。

种子萌发和幼苗阶段是植物生活史的关键阶段，决定着植物的存活及后续生长。东北地理所的科研人员研究了种子重量范围在0.16~3.29克的新疆12种苋科盐生植物对三种同浓度系列钠盐（氯化钠、硫酸钠和碳酸氢钠）的萌发生理生态响应。研究发现，大部分物种在同浓度的氯化钠中萌发率最高，然而有个别物种更耐硫酸钠和碳酸氢钠胁迫，因此评价盐生植物的耐盐性时要考虑多种不同类型的盐。

科研人员分析得出：在高盐条件下，种子大小与耐盐性成显著正相关，低盐条件下关系不显著。此外，他们还发现，不同的盐生植物采取不同的耐盐机制，有的是耐盐型，有的是避盐型。（来源：中国科学报 彭科峰）

Salt tolerance during seed germination and early seedling stages of 12 halophytes

Abstract  Aims  Most studies on plant responses to salt stress have focused on one salt (e.g., NaCl). The aim of this study was to investigate the salt tolerance of halophytes with different seed masses to three different salts during germination and early seedling growth stages. Methods  Seeds of 12 halophytes were imbibed with five concentrations of NaCl, NaHCO3, or Na2SO4 solutions or with distilled water. Germination was recorded for 20 days. Un-germinated seeds were transferred to distilled water and recovery of germination was recorded for another 20 days. We measured the Na+ and K+ concentrations in the seedlings after the germination experiments. Results  Most species showed higher germination percentages in NaCl than in NaHCO3 or Na2SO4 solutions. There were only significant differences in regressions of germination rates and salt concentrations for Anabasis salsa and Kalidium foliatum, between Na2SO4 solutions and the other salts. The Na+ concentration in the seedlings increased with increasing salt concentrations, while the K+ concentration was unchanged. Seed mass was significantly negatively correlated with the Na+/K+ ratio, and with decreasing germination percentage and decreasing germination rate at high salt concentrations. Conclusions  The halophytes showed species-specific responses to different salts. Some species were salt tolerators, while some were salt avoiders, as indicated by a high percentage recovery of germination in water after the alleviation of salinity. Seed mass was positively related to salt tolerance at high salinities.

原文链接：http://link.springer.com/article/10.1007/s11104-014-2322-3/fulltext.html