盐胁迫下黑果枸杞幼苗对外源甜菜碱的生理响应

以盐生植物黑果枸杞（Lycium ruthenicum）幼苗为试验材料，在300 mmol·L-1 NaCl胁迫下，用0.5、1.0和2.0 mmol·L-1甜菜碱根灌处理，第7和14天时测定黑果枸杞幼苗叶片主要生理指标的变化。结果表明，在盐胁迫下，黑果枸杞叶片叶绿素总量、质膜相对电导率、MDA、脯氨酸和可溶性糖含量均显著增加；在等盐分胁迫下，黑果枸杞幼苗经过甜菜碱处理后，MDA和膜透性伤害率显著降低，叶绿素总量、脯氨酸和可溶性糖的含量显著提高，并随胁迫时间的延长，有效抑制了MDA的产生，缓解了对细胞膜的伤害，同时进一步提高了叶绿素总量、脯氨酸和可溶性糖的含量。说明盐胁迫下施用适宜浓度的甜菜碱可改善黑果枸杞幼苗的耐盐能力，提高其对盐胁迫逆境的适应性。

Physiological response of Lycium ruthenicum seedling to exogenous betaine under salt stress

Lycium ruthenicum seedlings were treated with 0.5, 1.0 and 2.0 mmol·L-1 betaine by root irrigation under 300 mmol·L-1 NaCl stress to study physiological responses of L.ruthenicum to exogenous betaine under salt stress. Changes of main physiological indices of the seedlings were analyzed after 7 and 14 days of the treatments. The results showed that total chlorophyll, membrane permeability, malondialdehyde (MDA), proline and soluble sugar contents of L.ruthenicum leaves markedly increased in comparison with the control under salt stress condition. In the case of equal salt stress, MDA content and the damage rate of membrane permeability of the seedlings treated with betaine reduced markedly; while contents of chlorophyll, proline and soluble sugar increased significantly. Betaine had effective effects on inhibition of MDA generation and on alleviating damage of cell membrane, and also increased contents of total chlorophyll, proline and soluble sugar after root irrigation on L. ruthenicum seedlings. Applying the optimum concentration of betaine under salt stress can improve salt resistance of L.ruthencium seedlings and increase adaptabilities of salt stress condition.