灌浆期淹水胁迫对广西骨干玉米自交系生理生化特性的影响

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

【目的】探究灌浆期淹水胁迫下2个广西骨干玉米自交系在生理生化水平上的应答差异,为玉米耐涝性评价及耐涝栽培提供理论依据。【方法】以广西骨干玉米自交系88M-1-8和先21A为供试材料,设灌浆期授粉后正常水分处理14 d(CK-14)、18 d(CK-18)和淹水处理14 d(W-14)、18 d(W-18)共4个处理,分别测定不同处理玉米自交系的叶片含水量、叶绿素含量(SPAD值)、丙二醛(MDA)含量、脯氨酸(Pro)含量、脱落酸(ABA)含量及抗氧化酶活性,利用主成分分析和隶属函数法综合评价淹水胁迫对灌浆期玉米叶片生理生化特性的影响。【结果】88M-1-8在W-14时叶片含水量、SPAD值、SOD和POD活性均高于先21A,在W-18时叶片含水量、SPAD值、CAT活性和ABA含量均显著高于先21A(P<0.05,下同)。随着淹水天数的增加,88M-1-8叶片中CAT活性显著上升,Pro含量、SOD和POD活性显著下降;先21A叶片中MDA含量、SOD和POD活性上升,叶片含水量、CAT活性、SPAD值和ABA含量显著下降。与正常水分处理相比,淹水导致88M-1-8和先21A叶片POD活性、MDA和Pro含量上升,SPAD值和ABA含量下降,其中先21A变化幅度更大,差异均达显著水平。相关分析结果表明,叶片含水量与SPAD值呈极显著正相关(P<0.01),叶片含水量、SPAD值与MDA含量呈显著负相关,CAT活性与SOD活性呈显著负相关。利用主成分分析及隶属函数法对玉米叶片的8个生理生化指标进行综合评价,其结果为88M-1-8在W-14处理的耐涝性最强,在W-18处理的耐涝性次之;先21A在W-14处理的耐涝性第3,在W-18处理的耐涝性最差。【结论】灌浆期淹水胁迫可导致玉米叶片POD活性、MDA和Pro含量上升,SPAD值和ABA含量下降。自交系88M-1-8的变化幅度低于先21A,随着胁迫时间增加,88M-1-8的耐涝性明显优于先21A。CAT活性和ABA含量可作为玉米灌浆期叶片耐涝性的初步评价指标。

【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 pro-vide 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.