【作者】 杨琛；

【导师】 李晓刚；

【作者基本信息】 湖南农业大学 ， 农药学， 2012， 硕士

【摘要】 种子包衣已成为防治农作物病虫害重要手段。旱地作物用种衣剂已得到大面积推广,但南方水稻专用种衣剂应用严重不足。水稻包衣后存在有水环境,吸水耐水性和持效期要求高,成膜剂耐水性比旱田作物要求更高。因此,成膜剂的筛选,既要考虑成膜的包衣稳定性和耐水性,又要提高包衣的缓释性,提高持效期,确保种子发芽的安全性。稻瘟病是南方水稻苗期侵染性病害,研制长效控释性防治稻瘟病的水稻种衣剂是目前防治水稻苗期病害的一种新策略。鉴于此,本论文针对南方水稻稻瘟病防治,结合聚乙烯醇的功能化改性制备新型专用成膜剂,通过配方筛选实现水稻种衣剂的吸水耐水性和长效控释性。其主要研究内容如下：以聚醋酸乙烯酯、苯丙乳液对聚乙烯醇物理共混改性,合成了一系列水稻种衣剂专用成膜剂,单体比例为1：2：1的成膜剂脱落率3.26%、发芽率98.25%；光学显微镜显示三者单体配比为1：2：1时,成膜剂孔隙率小,浸水30d,成膜剂的破损程度较小；通过高效液相色谱法对不同浸水时间进行测定,浸水30d后,种衣中嘧菌酯的保持率为30%左右,缓释性能好,适合南方水稻种衣剂的成膜剂。通过对不同分散剂、成膜剂以及增稠剂的筛选,建立了以嘧菌酯为活性成份的水稻种衣剂新配方及制备工艺方法。10%嘧菌酯悬浮种衣剂的最佳制剂配方为嘧菌酯原药10%,YUS.FS30008%,黄原胶0.12%,快T0.5%,皂土0.5%,成膜剂8%。在砂磨转速500r/min,砂磨时间2h条件下,得到了种衣剂粒径小于3μm,其成膜性良好,脱落率小于5%,包衣后的水稻种子发芽率达到98.25%,符合水稻悬浮种衣剂要求。水稻种衣剂毒力测定和稻种室内安全性评价表明,嘧菌酯对稻瘟病病菌EC5o为0.0395μg/mL,包衣处理对水稻种子的发芽无不利影响,包衣后对水稻种子的发芽势和发芽率分别比未包衣的提高了0.83%和1.29%,株高和干重相对未包衣的水稻种子分别提高了1.3cm和1.2g,进一步验证了共混改性的水稻种衣剂成膜剂对种子性能促进作用,适合南方水稻种衣剂。更多还原

【Abstract】 Seed coating has been a key method of preventing plant diseases and insect pests. Seed coating formulation has been used widely in nonirrigated farmland,while application of seed coating special for rice in the south is severely insufficient. The main reason is that they live in different circumstances and have different demand on assistants. The rice seed coating lives in water environment, which has a high demand on water absorption resistence and pesticide persistence.The demand on water resistence of membrane agents is also higher than that used in nonirrigated farmland. Therefore, the choice of membrane agent need considering not only stability of the seed coating, water absorption and resistence but also its controlled release and persistence, which ensures the seed germinate normally. The rice blast is a kind of infectious diseases that arises in the south at the seeding stage, and the focus of present research is developing a rice seed coating agent of long-term controlled-release type in order to prevent the rice blast at the seeding stage.Aiming at rice blast control,the thesis of this paper is to accomplish water resistence and long-term controlled-release of rice seed coating agent through formula screening combined with functional modification of the polyving akohol.The following contents are main studies:A series of membrane agents special for rice seed coating were synthesized by blending polyvinyl acetate, styrene-acrylic latex and modified PVA.When the monomer ratio was1:2:1, synthesized membrane agent had a low shedding rate of3.26%,high germination rate of98.25%;Observation under optical microscope showed that porosity of membrane agent was small and breakage of membrane agents for30days in the water was low. Azoxystrobin amount after different soaking time was determined by HLPC.The retention rate of azoxystrobin after30d soaking was about30%with favorable controlled-release,which is suitable for membrane agents of the rice seed coating in the south.Through screening different dispersant, membrane agents and thickening agents, a new formula and preparation method for rice seed coating using by using azoxystrobin as active ingredients was established. The optimum formula of10%azoxystrobin seed coating was10%azoxystrobin,8%YUS-FS3000,0.12%gum,0.5%quick T,0.5%soap soil,8%membrane agents.At grinding speed of500r/min for2h, the size of the rice seed coating was less than3μm, shedding rate was less than5%, and germination rate of the seed coating reached98.25%.Toxicity test and security assess of rice seed coating showed that azoxystrobin had perfect controlling effect on rice blast with EC50value of0.0395μg/mL, and seed coating had no adverse effect on germination of rice seed. The germination power and germination rate increased respectively by0.83%and1.29%compared with CK. Meanwhile,plant heigt and dry weight increased respectively1.3cm and1.2g compared with CK. So the membrane agent of the rice seed coating can enhance seed performance and is suitable for rice seed coating agent in the south.更多还原