Studies On Preparation,Action Mechanism And Biological Effect Of Soaking Suitable Rice Seed Coating Agent

This thesis includes three parts. In the first part, 23 kinds of film-forming materials, 60 kinds of assistants, 15 kinds of pesticides and fungicides and 17 kinds of plant growth regulators and micro nutrients were used as tested materials to prepare soaking-suitable rice seed coating agent(Hongli rice seed coating agent).In the second part, rice seeds were coated to explore the mechanism of slow-release, entering seedling and content change hi seedlings of active ingredients in the seed coating agent. In the third part, some rice varieties(such as Jinyou 402) tested were studied the biological effects of the seed coating agent by using indoor and outdoor seedling raising and field cultivation. Main results are as follows:1 The property of soaking-suitable rice seed coating agent with compound film-forming materials TJW7j JHW3 and QWYs was better than that with single one, which can overcome film dissolving hi water or no film pore of that with single film-former. The general property of this seed coating agent was best when FM, IW, octanol, ethandiol and so on were used as its assistants.2 The prevention and controlling effects of this seed coating agent on diseases and pests during seedling period were very obvious when prochloraz and imidacloprid were used as its fungicide and pesticide with a mix ratio of 4 to 9. Its effects on regulating seedling growth, enhancing seedling qualities and increasing seedling resistance to reverse environments were remarkable when NAA, DBA, BR DCPTA, PP333, uniconazole, copper, zine, manganese and molybdenum were used as plant regulators and micro nutrients hi this seed coating agent.3 This seed coating agent has good film-forming property, uniform film coated around seed and low separation rate of the film. The coating film was not soluble but expansible hi water, so the damage rate of active ingredients was less than 8.0% after coated seeds soaked at 25 癈 for 48 hours. The coated seeds soaked and pregermined can be used as non-irrigation nursery, semi-irrigation nursery or directly sown on soils, which suits to farmer's customs of rice cultivation. The coating film has many membrane pores (average pore size and density are 0.22um and 1.6 X 104 pores/mm2, respectively) and good permeability, which can not only guarantee the freely entering of water and oxgen necessary to seed germination into the seed, but also lay a foundation for slow-release of the active ingredients. The general property is obviously better than that of Shileshi seed coating agent made in Switzerland and similar seed coating agents made in China.4 Active ingredients in the coating film release slowly through membrane pores, and their slow-release rates and velocities depend on factors such as their properities and concentrations hi the seed coating agent. The slow-release rate sequence was magnesium >zhie>hnidacloprid>paclobutrazol. Active ingredients released can be absorded notillonly by seedling roots, but also by seed embryo, and translocated to seedling parts above underground to play their roles.5 The contents of active ingredients in seedling decreased gradually but their weight increased within 60 days after coated seeds were sown, which showed that the plant was absorbing and moving these ingredients all the lime. The absorption degree was higher than the degradation degree of the ingredients, and the effects of the ingredients can last longer.6 This seed coating agent can obviously enhance the activities of pexoxidase (POX), catalase (CAT) and superoxide dismutase (SOD) as well as the contents of proline and soluble sugars, which lays a physiological foundation for increasing seedling resistance to reverse environments. The activities of POX, CAT and SOD increased 17.0%~26.3%, 7.0%~ 10.1% and 1.1%~1.7% compared with uncoated controls, respectively. The proline content increased by 61.1 %?166%.7 Seed coating can obviously increase the contents of 3-indoleacetic acid (IAA) and gibberellin (GAs) and decrease abscisic acid (ABA) co...