Evaluation On Biological Efficiency And Application Effects Of Cold Resistant Seed Coating Agents Of Rice

The influences of 4 cold resistant seed coating agents HET, YKJ, ABA and SNCon 9 items of physiological and biochemical indexes, such as root vigor, chlorophyllcontent, proline content, soluble sugar content, soluble protein content,peroxidase(POD), catalase(CAT) and superoxide dismutase(SOD) activities,electrolyte leakage and malondialdehyde(MDA) content, etc., were studiedsystematically under chilling stress in growth chamber and fields by using ricevarieties Jinyou974 and Xiangzaoxian31 as materials. And then the application effectsof the prepared cold resistant seed coating agents were studied. The main results areas follows:1. Under normal condition, the 4 kinds of cold resistant seed coating agentsraised obviously the root vigor, the contents of chlorophyll, soluble sugar, free proline,growth hormones as well as the activities of peroxidase(POD), catalase(CAT) andsuperoxide dismutase(SOD), decreased the content of malondialdehyde(MDA) andelectrolyte leakage, which laid a physiological foundation for raising vigorousseedlings and increasing the seedling's suitability to reverse environments.Under chilling stress, the cold resistant seed coating agents maintained a ratherhigh level of root vigor and chlorophyll content, which guaranteed keeping seedlingsa normal nutrient absorption, higher photosynthetic power and normal growth andstrengthening the resistance to reverse environments. The cold resistant seed coatingagents accelerated the growth of seedlings and prolonged the functioning time ofleaves by preserving a high level of growth hormones as auxin(IAA), gibberellin(GA₃) and zeatin(Z) in seedlings; the membrance system was protected by enhancing largeaccumulation of soluble sugar, proline and abscisic acid(ABA) and reducing thedecline of soluble protein, which laid a physiological foundation for strengthening thecold resistance of seedlings. The cold resistant seed coating agents reduced theelectrolyte leakage and the decline of COD, CAT, POD activities, kept a low level offree oxygenic radical, decreased the accumulation of MDA, which ensured thephysiological and biochemical HETabolism conducted as usual. As a result, the plantswere prevented from cold damage.According to integrated evaluation of 9 items of physiological and biochemicalindexes, YKJ+SNC was the best, then YKJ and ABA, and the last HET in 4 coldresistant seed coating agents in effect of resistant cold.2. The resistant frequency of 2 rice varieties coated with YKJZYJ seed coatingagent against 14 kinds of blast isolates usually seen in Hunan were 75％～93.75ï¼…,25.5～31.25 percentages more that than of CK, which revealed that the inducingresistance were broad spectrum; The effects of inducing resistance were74.81％～80.57ï¼…, in which the hybrid rice was superior to the conventional rice.3. In the experiment of direct seeding of 3'early-rice varieties coated with 3kinds of seed coating agents, HET, YKJ and YKJZYJ, adult seedling rate, seedlingqualities and cotd resistance were obviously enhanced, and rotten seedling rate wasobviously decreased. Adult seedling rate increased by 10～11.6 percentages, plantdamage rate decreased by 53.9～63.7 percentages and yield increased by 8.2％～17.6ï¼….The effect of YKJZYJ was the best among three kinds of seed coating agents tested.4. Applying under conventional condition, the total effect of YKJZYJ wassuperior to the effects of seed coating agents applied in production such as JiangsuHuanong and Sichuan Hongzhongzi produced in China and Shileshi imported fromSwitzerland.