Effect of Seed Coating Agents on Growth and Disease Resistance RelatedEnzymes of Shannong Feed Corn No.7 Seedling

The effect of three seed coating agents on the growth of Shannong feeding maize No.7 was determined by sand bioassay.The results indicated that imidacloprid-tebuconazole(5%+0.4%)seed coating agent (the pesticides and seed mass ratio is 1∶ 100) increased the height of maize,length of tap root and fresh weight by 1.68 cm,2.44 cm and 0.17 g respectively,comparing with the control,and the effect was better than that chlorpyrifos-tebuconazole-thiram(5%+0.3%+15%)seed coating agent.However,carbofuran-thiram-triadimefon(7%+7%+1%)seed coating agent restrained the growth of the maize.In vitro study it showed that imidacloprid-tebuconazole seed coating agent could increase the activity of disease resistance related enzymes in both above ground and the underground parts of the seedings,with superoxide dismutase (SOD) specific activity being improved by 47.1% and 100.2%,and phenylalanine ammonialyase (PAL) specific activity being enhanced by 59.5% and 58.6% respectively;meanwhile,the content of malondialdehyde (MDA) being decreased by 54.0% and 26.2%,respectively.The activity of catalase (CAT) and peroxidase (POD) was also increased in different degree.The effect of 5.4% imidacloprid-tebuconazole seed coating agent on the activity of disease resistance related enzymes increase obviously and promote seedling growth significantly.