Table_4_Salt-Enhanced Reproductive Development of Suaeda salsa L. Coincided With Ion Transporter Gene Upregulation in Flowers and Increased Pollen K+ Content.docx

Halophytes are adapted to saline environments and demonstrate optimal reproductive growth under high salinity. To gain insight into the salt tolerance mechanism and effects of salinity in the halophyte Suaeda salsa, the number of flowers and seeds, seed size, anther development, ion content, and flower transcript profiles, as well as the relative expression levels of genes involved in ion transport, were analyzed in S. salsa plants treated with 0 or 200 mM NaCl. The seed size, flower number, seed number per leaf axil, and anther fertility were all significantly increased by 200 mM NaCl treatment. The Na+ and Cl− contents in the leaves, stems, and pollen of NaCl-treated plants were all markedly higher, and the K+ content in the leaves and stems was significantly lower, than those in untreated control plants. By contrast, the K+ content in pollen grains did not decrease, but rather increased, upon NaCl treatment. Genes related to Na+, K+ and, Cl− transport, such as SOS1, KEA, AKT1, NHX1, and CHX, showed increased expression in the flowers of NaCl-treated plants. These results suggest that ionic homeostasis in reproductive organs, especially in pollen grains under salt-treated conditions, involves increased expression of ion transport-related genes.盐生植物（Halophytes）适应盐渍环境，在高盐条件下可实现最优的生殖生长。为深入解析盐生植物碱蓬（Suaeda salsa）的耐盐机制及盐胁迫的影响，本研究对经0 mM与200 mM氯化钠（NaCl）处理的碱蓬植株，开展了花与种子数量、种子大小、花药发育状况、离子含量、花转录组谱以及离子转运相关基因相对表达水平等多维度指标分析。经200 mM NaCl处理后，碱蓬的种子大小、花数量、每叶腋处的种子数以及花药育性均显著提升。与未处理对照组相比，经NaCl处理的植株其叶片、茎秆及花粉中的钠离子（Na+）和氯离子（Cl−）含量均显著升高，而叶片与茎秆中的钾离子（K+）含量则显著降低。与之相反，经NaCl处理后花粉粒中的钾离子含量并未下降，反而有所升高。与Na+、K+及Cl−转运相关的基因（如SOS1、KEA、AKT1、NHX1和CHX）在经NaCl处理植株的花中均呈现表达上调。上述结果表明，生殖器官（尤其是盐处理条件下的花粉粒）中的离子稳态，依赖于离子转运相关基因的表达上调。