Effects of waterlogging stress during filling stage on physiological and biochemical characteristics of backbone maize inbred lines in Guangxi

【Objective】The purpose of the study was to investigate the differences in physiological and biochemical responses of two backbone maize inbred lines in Guangxi under waterlogging stress during the filling stage，so as to provide a theoretical basis for waterlogging-tolerance evaluation and cultivation of maize.【Method】Four treatments were set up：the normal water treatments of 14 d（CK-14）and 18 d（CK-18）and the flooding treatments of 14 d（W-14）and 18 d（W-18） at the filling stage after pollination. The leaf water content，chlorophyll content（SPAD value），malondialdehyde（MDA） content，proline content，abscisic acid（ABA）contents and autioxidant enzyme activities of maize inbred lines were separately measured after different treatments，respectively. Effects of flooding stress on physiological and biochemical characteristics of maize leaves at filling stage were comprehensively evaluated using principal component analysis and membership function method.【Result】At W-14，leaf water content，SPAD value，SOD and POD activities of 88M-1-8 were higher than those of Xian 21A，and at W-18，leaf water content，SPAD value，CAT activity and ABA content were significantly higher than those of Xian 21A（P＜0.05，the same below）. As the number of days of flooding increased，CAT activity significantly increased and Pro content，SOD and POD activities significantly decreased in 88M-1-8 leaves； MDA content，SOD and POD activities increased，and leaf water content，CAT activity，chlorophyll and ABA content significantly decreased in Xian 21A leaves. Compared with the normal water treatment，flooding resulted in a significant increase in POD activity，MDA and Pro contents，and a significant decrease in SPAD value and ABA content in the leaves of 88M-1-8 and Xian 21A，among which the change of Xian 21A was larger and the difference was significant. The results of correlation analysis showed that leaf water content was extremely significantly and positively correlated with SPAD value（P＜0.01，the same below），both were extremely significantly and negatively correlated with MDA content， and CAT activity was significantly and negatively correlated with SOD activity. The eight physiological and biochemical indicators in maize leaves were comprehensively evaluated and analyzed by principal component analysis and membership function method，and the results were as follows：the waterlogging tolerance of 88M-1-8 under W-14 treatment was the strongest，the waterlogging tolerance under W-18 treatment was the second，and the waterlogging tolerance of Xian 21A under W-14 treatment was the third，and the waterlogging tolerance under W-18 was the worst.【Conclusion】Flooding stress at filling stage can lead to increase of POD activity，MDA and Pro contents，and decrease of SPAD value and ABA content in maize leaves. The variation range of the inbred line 88M-1-8 is lower than that of Xian 21A. With the increase of stress time，the waterlogging tolerance of 88M-1-8 is higher than Xian 21A. CAT activity and ABA content can be used as preliminary evaluation indicators for waterlogging tolerance of maize leaves during the filling stage.