The Actions Of ABA And H₂O₂on The Expression Of SHSPs And Antioxident Defense Enzyme Of Maize Varieties With Different Endurance Induced By The Combination Of Drought And Heat Stress In Different Varieties Of Maize

In order to determine the mechanism of heat shock protein （HSPs） andABA protecting maize （Zea mays L.） from the combination of drought and heat stress,four maize varieties of Zheng dan958with drought edurance, Xundan20with heatendurance, Longyu602with endurance to the combination of drought and heat stress,Zhuyu309with sensitivation to three stresses. cavenger Flu（F） were used to analyse theinfluences of ABA, cavenger KI（I） and P were used to analyse the influences of ABAand H₂O₂on sHSPs and antioxidant defense enzymes genes expression induced by thecombination of drought and heat stress in maize leaves The detailed research results areas follows.1、In determination sHSP16.9, sHSP17.2, sHSP17.4, sHSP17.5, sHSP22and sHSP26six sHSPs,sHSP17.2only expressed in Zheng dan958with drought edurance, while theother four different tolerance of maize varieties were expressed.2、In addition to the sHSP17.2outside, the five other sHSP expression in the heat stressand combination of drought and heat stressthan the drought and control;ABA andinhibitor fluorine （F）and H₂O₂scavenger KI,（I） and sodium pyruvate （P） after thestress is only slightly affected sHSP16.9, sHSP17.2, sHSP17.5, sHSP22and sHSP26five the relative expression level of the kinds of sHSP, and sHSP in the combinationof drought and heat stress, heat which was significantly higher than that of drought, inaddition to sHSP22outside, the other four sHSP are in the Longyu which express thehighest among the lowest in zhuyu.3、After treatments, catalase （catalase, CAT）, ascorbate peroxidase （ascorbate peroxidase, APX）, glutathione reductase （glutathione reductase, GR）, three antioxidantdefense gene expression is: ABA varying degrees of increase in the relativeexpression level of GR and APX, the CAT gene, F, I, P three treatments reduced tovarying degrees relative expression levels of antioxidant defense enzymes. InZhengdan958, Xundan20, Longyu602leaves, the increase of APX, GR, CATactivities was more than that in Zhuyu309leaves under drought, heat, thecombination of drought and heat; under drought, APX, GR, CAT activities of Zhengdan958leaves increased significantly more than those of Xundan20’, butthose were contrary under heat; under the combination of drought and heat, APX,GR activities of Longyu602leaves increased significantly more than those ofZhengdan958and Xundan20.4.The results of sHSP26expression analysed by western blot showed that, sHSP26wassignificantly inhabited by KI in maize leaves, sHSP26expression of performanceand in the Longyu which is more obvious, the largest increase in the heat. Thisshows the level of transcription and translation levels sHSP26of the expression isnot the same.Our results show that the sHSPs and antioxidant protection system in a differenttolerance to corn varieties expression exist significant differences, the ABA andH₂O₂significantly improve the four different tolerance corn varieties,anti-oxidation protective gene expression, but only slightly improve thesHSPs geneexpression. However, significantly to improve sHSP26protein expression onH₂O₂.These results supplied the basis for further researching the mechanisms ofplant response to stress and gene cloning, and also offered important scientificevidences to reveal the mechanism of plants tolerant to combination stress.