盐胁迫对四种基因型冬小麦幼苗Na+、K+吸收和累积的影响

以4种不同基因型冬小麦品种为试验材料，研究了盐胁迫下小麦幼苗的生长及Na^＋、K^＋和Cl^-的吸收、累积规律。结果表明，盐胁迫下小麦吸水困难，幼苗生长受抑；幼苗含水量、生物量及干物质量明显下降；Na^＋、Cl^-含量和单株累积量显著增加。K^＋含量和单株累积量则明显降低。Na^＋／K^＋比值随介质中的盐浓度的增加而升高。盐胁迫下各基因型冬小麦幼苗Na^＋、K^＋和Cl^-的单株累积量及其在地上部分和根系中的含量变化较大，说明小麦根系对Na^＋、K^＋和Cl^-的吸收存在基因型差异。盐处理下，暖型小麦NR9405对K^＋的选择吸收能力强，对Na^＋的吸收和累积少，植株体内的K^＋浓度较高，Na^＋／K^＋比值小；幼苗的生物量较大，耐盐性强。冷型小麦RB6对K^＋的选择能力差，对Na^＋的吸收和累积量大，幼苗的Na^＋／K^＋比值大，生物量小，耐盐性较差。低盐浓度下，Na^＋可作为渗透调节物质维持植物体内渗透平衡。高盐浓度下，Na^＋的过度吸收和累积可能是盐害的主要原因。维持体内较低的Na^＋水平和Na^＋／K^＋比值是小麦耐盐性的一个重要特征。

Effects of salt stress on the absorption and accumulation of Na+ and K+ in seedlings of four winter wheat (Tritium aestivum) genotypes

This research investigated the growth response and Na + and K + absorption and accumulation in seedlings of four winter wheat genotypes under salt stress. The results showed that the water content, biomass, dry weight, and K + concentration and accumulation of the seedlings decreased greatly under salt stress. In contrast, the concentration and accumulation of Na + and Cl - in the seedlings increased. The Na + /K + ratio in the seedlings increased as the salt concentration increased in the growth medium. There were differences in the concentration and accumulation of Na + and Cl - among the wheat genotypes, which indicated that wheat roots had genotypic differences in total absorption of Na + , K + and Cl - . Genotype NR9405 has a higher canopy temperature compared to the other genotypes. Under salt stress, it had a higher capacity for selective K + uptake and lower Na + uptake and translocation compared to the other genotypes. As a result, it had a higher cytosolic K + concentration and a lower Na + /K + ratio. It also had greater biomass production compared to the other genotypes. In contrast, genotype RB6 has a relatively low canopy temperature. Our results indicated that it had a lower capacity for K + uptake and a higher capacity for Na + accumulation compared to the other genotypes. This resulted in a higher Na + /K + ratio and lower biomass production. Na + entering the plant could function as an osmotica and adjust the osmosis potential and maintain the osmosis balance under low NaCl concentration. Excessive Na+ absorption is one of the main causes of plant injury and a reduction in growth under high salt stress. The ability to maintain a low cytosolic Na~+ concentration and a small Na~+/K~+ ratio could be a major characteristic of salt tolerance in wheat.