High Temperature Stress On Physiological Characteristics And The Related WRKY Gene Expression Quantity Of Maize

As the greenhouse effect intensifies,global climate warming trend is irreversible.The frequency and intensity of high temperature stress are gradually increasing,and time of occurrence has a tendency to ahead,which will affect the growth of maize seedlings and harm summer corn in China.In this study,by analyzing Huangzao4,8112,478 and Lv9 kuan changes rules of chlorophyll fluorescence parameters,chlorophyll content,antioxidant enzyme activity and membrane lipid peroxidation were determined by continuous high temperature treatment of 40℃ in maize.The evolutionary tree analysis of the nucleotide sequence of maize,Arabidopsis and Rice was established to select the WRKY family gene that might participate in the stress response in maize.By analysis the expression of WRKY genes to obtain the gene get involved in high temperature stress.The main results are as follows:1.Analyzing the content of chlorophyll and fluorescence parameters after high temperature stress treatment,compared with 478 and Lv9 kuan,the chlorophyll fluorescence parameters(Fv/Fm,Y(II),q P and q N)and the content of chlorophyll(chlorophyll a and chlorophyll b and carotenoids)of Huangzao4 and 8112 changed in small;Antioxidant enzymes activity and membrane lipid peroxidation material analysis found that,the SOD,CAT and POD activity of 478 and Lv9 kuan are lower and changing much more than Huangzao4 and 8112,the trend of MDA content and relative conductivity is same as before and even more significant;In other words,Huangzao4 and 8112 have stronger ROS scavenging ability and thermal stability,and degree of cell membrane damage is smaller than 478 and Lv9 kuan during treatment.Comprehensive analysis this physiological indexes,compared with 478 and Lv9 kuan,Huangzao4 and 8112 in seedling stage have more ability to tolerance high temperature.2.Verified the amount of gene expression,found that the expression of ZmWRKY22,ZmWRKY23,ZmWRKY30,ZmWRKY65 and ZmWRKY82.2 in Huangzao4 induced by high temperature stress were increasing,and all of them peaked at 8h;ZmWRKY25 and ZmWRKY92.1 were up-regulated in all of inbred lines;in Lv9 kuan,478 and 8112 the express of ZmWRKY31 were significantly up-regulated,and change little in Huangzao4.The smooth conduct of experiment not only have the advantages of revealing the regulatory mechanism of maize when response to heat stress,but also provide reference for maize germplasm resources and breeding.