Effects of PEG stress on phytomass,active oxygen metabolism and proline content of Leymus chinensis seedlings under split-root condition

Chinese. 采用分根装置,在自动控制的遮雨棚中,研究了聚乙二醇（PEG）胁迫对羊草幼苗植物量、活性氧代谢以及脯氨酸含量的影响.结果表明：与对照（CK,1/2强度Hoagland营养液）相比,单一根茎胁迫（RHS）、单一根系胁迫（ROS）以及同时根茎和根系胁迫（RHSS）3种处理方式均显著降低了羊草幼苗地上部干重、根茎干重以及总干重,且ROS处理和RHSS处理的降低幅度较大.RHS处理时,羊草幼苗根系中SOD、CAT活性显著降低,而根茎SOD、CAT活性增加.ROS和RHSS处理下,叶片中SOD、POD和CAT活性均有上升趋势;根茎在ROS处理下SOD、CAT活性均增加,RHSS处理下仅SOD活性上升,而根系在ROS处理下仅CAT活性上升.羊草地上部脯氨酸含量在RHS、ROS和RHSS处理时均显著增加,而根茎则显著降低.可见,根茎和根系在羊草响应PEG胁迫的生理过程中具有不同的功能;PEG胁迫下羊草不同器官同一抗氧化酶对活性氧淬灭作用不同,与POD相比不同器官SOD和CAT作用可能更大.[著者文摘]

English. A split-root experiment was conducted to investigate the effects of PEG stress on phyto mass,active oxygen metabolism and proline content of Leyrnus chinensis seedlings in auto-rain-shelter greenhouse. The results showed that, compared with control （CK, 1/2 strength Hoagland solution）, the three treatments,namely RHS（only rhizome was stressed）,ROS（only root was stressed） and RHSS（both rhizome and root were stressed）,decreaseed dry biomass of shoot,rhizome and the whole plant significantly. Under RHS treatment,SOD and CAT activities in root were decreased,while increased in rhizome. Under ROS and RHSS treatments, SOD, POD and CAT activities in leaves showed an increasing tendency. The SOD and CAT activities in rhizome were decreased under ROS treatment , but to RHSS treatment , only SOD activity in rhizome was increased. As for root,only CAT activity was increased under ROS treatment. In addition, significant differences were found in proline content in different organs under PEG stress, namely,proline content increased in shoot while decreased in rhizome under three treatments of RHS,ROS and RHSS. This result above suggested that rhizome was important in sensing and responding to PEG stress,and had difference in function to roots. The same antioxidized enzyme in different tissues~of Leymus chinensis seedlings has different effect on the quenching of active oxygen, among which SOD and CAT might have more important roles in owning to higher activities under the stress.