硅对盐胁迫下枣组培苗生根培养效果、体内离子稳态及膜脂过氧化的影响

以泗洪大枣微茎段增殖扩繁苗为试材,研究了NaCl 75 mmol/L胁迫下生根培养基中加Si(K2SiO30.75 mmol/L)与否对枣树组培苗生根培养效果、体内离子稳态及膜脂过氧化的影响。结果表明:盐胁迫下枣树微茎段外植体成活率和生根率显著降低,生根枣苗的侧根条数、侧根平均长度、株高和单株重量均显著减小,盐胁迫下加Si处理的这些指标则显著升高或增大而与对照无显著性差异。盐胁迫下枣树组培苗体内Na+、Cl-含量均较对照显著升高,K+/Na+显著减小;盐胁迫下加Si枣苗体内Cl-含量减少,与对照无显著差异;Na+含量和K+/Na+虽然显著高于对照,但显著低于不加Si处理。盐胁迫下生根培养基中加Si与不加Si相比,枣树组培苗体内谷胱甘肽过氧化物酶(GPX)等抗氧化酶系统应激响应明显趋于平缓,细胞质膜透性显著减小,丙二醛(MDA)含量则无显著差异。说明,盐胁迫下加Si优化枣树生根培养基条件,增强组培枣苗对盐分离子的选择性吸收功能,利于保持盐胁迫下枣树组培苗体内的离子稳态,诱导对膜脂过氧化作用抗性的提高。

Genetic Variation in Salt Stress Response and Germplasm Resource Evaluation among <i>Lycium</i>Accessions

Genetic variation between naturally occurring ecotypes can be helpful to elucidate the mechanism controlling salt stress response in different environments. The salt stress response of 20 natural accessions or cultivars of Lycium was characterized at a physiological level, following exposed to 300 mM NaCl for 15 days. It is shown that salt stress increased Na+, betaine and malondialdehyde (MDA) content, as well as the relative permeability of plasma membranes, but decreased K+, chlorophyll and glutathione (GSH) content, as well as K+/Na+ ratio compared with their respective control value in most of the varieties, though the increasing or decreasing extent has a clear genetic diversity. The physiological response was utilized to evaluate the salt-tolerant capacity of these varieties by principal component analysis and clustering analysis, and in which total chlorophyll, K+/Na+ ratio and partially GSH have the maximum weight relatively. These varieties could be categorized into four sub-groups, means greatly resistance (Heiguo, Ninqi No. 2 and Beifang), moderately resistant, sensitive, and mostly sensitive (Ninqi No. 7) to salt stress. Our results provide a theoretical basis and practical guidance for the improvement of saline-alkali land and rational utilization of Lycium germplasm resources in the future.