NaCl分根胁迫对羊草幼苗生长及其生理生化特性的影响

Effects of NaCl Stress on Growth and Its Physiological-biochemical Characteristics of Split-root Leymus chinensis Seedlings

在自动控制的遮雨棚中,研究了200 mmol·L-1NaCl胁迫对不同分根处理羊草幼苗生物量、活性氧代谢以及渗透调节物质含量的影响.结果表明:单一胁迫根茎(RHS)、单一胁迫根系(ROS)以及同时胁迫根茎和根系(RHSS)3种处理方式下羊草幼苗各器官干重均低于对照,且大体呈现RHSS>ROS>RHS趋势.在RHS和ROS处理下,羊草叶片和根茎SOD、POD、CAT活性及MDA含量均无显著差异;RHSS处理时根系中SOD、CAT活性相比ROS处理显著降低.3种处理下根茎和根系MDA、可溶性糖、脯氨酸含量均显著高于对照,可溶性糖、脯氨酸含量在RHS和ROS处理间存在显著差异.可见,根茎在羊草响应盐胁迫的生理过程中与根系具有类似的功能;盐胁迫下羊草不同器官同一抗氧化酶对活性氧淬灭具有不同的作用,与POD相比不同器官SOD和CAT作用可能更大;根茎可能参与光合同化物——可溶性糖在羊草地上部和地下部的调节运输,且协同根系增强了羊草对盐胁迫的耐性作用.

An experiment was conducted to investigate the effects of salt stress on biomass,activated oxygen metabolism and osmoregulation content of split-root Leymus chinensis seedlings in an auto-rain-shelter greenhouse. The results showed that, compared with controls, three treatments, namely RHS （only rhizome was stressed） ,ROS （only root was stressed） and RHSS （rhizome and root were all stressed） ,decreased dry biomass of different tissues with the decreased range for RHSS〉ROS〉RHS. Under RHS and ROS treat- ments,SOD, POD, CAT activities and MDA contents in leaves and rhizomes changed no significantly; compared with ROS,SOD and CAT activities in roots decreased significantly under RHSS treatment. MDA, soluble sugar and proline contents in rhizomes and roots were higher than those in controls under three different treatments,and also soluble sugar and proline contents had significant differences between RHS and ROS. These results suggested that,rhizomes are important in sensing and responding to salt stress,and have a similar function as roots;The same antioxidized enzyme has different effect on the quenching of activated oxygen in different tissues of L. chinensis seedlings,among which SOD and CAT may had more important roles owning to their higher activities under the stress; Rhizome may participate in the regulation and transportation of photosynthate, viz soluble sugar in shoots and roots, and may coordinate with roots to enhance the tolerance of L. chinensis seedlings to salt stress.