硅对大麦耐盐性的影响及其机制

研究了水培和土培条件下硅对盐敏感大麦（Hordeum vulgare L.）科品7号和耐盐大麦鉴4耐盐性的影响及其作用机制。结果表明，水培和土培条件下适量加硅可降低大麦的盐害。硅显著提高盐胁迫大麦根系脱氢酶活性，降低叶片细胞汁液浓度。硅可显著提高盐胁迫下大麦体内的钾离子浓度、降低钠离子浓度，并提高土培大麦植株体内氮、磷的积累量及磷的浓度，改善盐胁迫大麦植株的养分平衡状况。硅对耐盐大麦盐害的缓解效果比对盐敏感大麦更显著。硅对大麦耐盐性的影响主要是通过降低钠离子毒害、减轻水分胁迫程度和改善植株体内的养分平衡状况而实现的。硅参与了植物的代谢或生理活动。

Effects of Silicon on Salt Tolerance of Barley and Its Mechanism

Two barley (Hordeum vulgare L.) cultivars, Kepin 7 (salt sensitive) and Jian 4 (salt tolerant), were grown in both a hydroponics and a soil culture system for the investigation of silicon (Si) and salt (NaCl) interactions and their possible mechanism(s). The results indicated that the addition of soluble Si to both solutions and pot soils significantly improved salt tolerance of barley. Compared with the plants treated with salt alone, dehydrogenase activity in plant roots increased significantly for both cultivars when the salt-affected media were treated with Si. Addition of Si markedly decreased leaf cell sap concentration in the leaves of plants exposed to salinity at tillering, which strongly suggests that Si may help to alleviate water stress induced by salinity. Additionally, it was also found that the addition of Si reduced sodium but incrected soils significantly improved the nutrient balance of salt-stressed barley by increasing phosphorous concentration and content and nitrogen content in plants. Thus, Si-enhanced salt tolerance in barley plants is attributed to the decreased sodium ion toxicity and osmotic stress, and to the improvement of nutrient balance. The results of the present study strongly suggest that Si is involved in the metabolic or physiological changes in higher plants.