| In order to study the specific reasons why it occured phytotoxicity risk in the actual production of wheat, the effects of seed-coating triadimefon on seed germination have been studied in this paper. The results indicated that the germination index, seed vigor index and germination rate of coated wheat seeds were negatively correlated with the dose of triadimefon, and their relationship satisfied with function Y=A+B×e(-x/k), and the sensitivity of the different variations to the dose of triadimefon were different. It determined the cold resistance related physiological and biochemical factors in plumules of Zhou mai 22 wheat seeds detailedly comparing with difenoconazole, and based on this, the effect of seed-coating triadimefon on the gene expression related cold resistance factors have been further studied. From these results above, the effect of seed-coating triadimeon on wheat plumules have been preliminary understood. Results are as follows:1. It was found that the triadimefon treatment could lead to lower GAs contents and higher ABA contents in shoots when compared to the control. For example, at the dose of 0.6 g/kg, the GAs content decreased to 37.6% and ABA content increased to 2.1 times compared to the control. And the variation of GAs and ABA contents showed increased trends with the increase of triadimenfon dose, which theoretically explained the dose dependent suppression of triadimenfon on wheat seed germination. Biochemical analysis revealed that triadimefon could lead to higher chlorophyll content, respiratory rate, soluble protein content and activity of ?- amylase, and the lower electrolyte leakage than the control treatment in renascent shoots. Comparatively, difenoconazole showed less suppression on wheat seed germination and was more helpful to improve the potential cold resistance of wheat shoots when compared to triadimefon.2. The test determined the effect of seed-coating triadimefon on stress-resistance factors of wheat plumules at the low temperature stress. The results showed that the electrolyte leakage of wheat plumules decreased with the increasing dose; The activity of SOD, POD and CAT of wheat plumules with triadimefon treatments changed different with the increasing dose of triadimefon, CAT activity reduced and POD activity increased, and SOD activity decreased by 73.6% compared with control at the dose of 0.6 g/kg; The AsA content increased with the increasing dose, and key enzyme activity in the process of ascorbic acid synthesis were changed; At the same time, it measured the gene expression quantity of relative enzyme and the results indicated that it can promote the gene expression at the dose 0.05 to 0.075 g/kg with triadimefon treatments. It can further explain that the effect of seed-coating triadimefon on the growth of wheat at low temperature stress, and difenoconazole treatment can improve the cold resistance of wheat.3. Based on three kinds of cold resistance genes Wcor14, Wcor410 and Wcs120 determination of the amount of gene expression, it showed that under the low temperature stress, three kinds of cold hardiness genes will be induced to express and three genes had significant influence with the treatment of triadimefon. Wcor14 gene was down-regulated with the increasing dose and Wcor120 gene was upregulated. Within the dose of 0.075 to 0.6 g/kg, three kinds of gene expression quantity of wheat with difenoconazole treaments were higher than that of triadimefon coating processing. It suggests that it has a certain influence to the expression of the three cold-resistance genes with triadimefon treatment, but difenoconazole can promote three cold resistance genes expression and it can enhance the resistance to low temperature environment.In conclusion, it inhibited the seed germination with seed-coating triadimefon and the sensitivity of the different variations to the dose of triadimefon was different. Meanwhile, it can promote the cold resistance of wheat plumules at the low dose and it reduced the resistance at the high dose. And it was inferior to difenoconazole. |
