水稻纹枯病（R. solani）以“菌丝-菌核-菌丝”无性繁殖，且以菌核的形式抵御现有药剂的作用，使得难以根治。本项目根据水稻纹枯病菌核的内外层组成与结构特性，设计合成了一类以聚硅氧烷（PDMS）为疏水嵌段、含季铵盐侧基的聚合物（PQAS）为亲水嵌段、兼具大分子表面活性剂和大分子杀菌剂特性的两亲性大分子季铵盐（PDMS-b-PQAS），它可通过亲-疏水作用稳定吸附在菌核表面，继而浸润、渗透菌核的疏水性外层，抑制/破坏菌核萌发初期产生的菌丝及菌核内层活性菌丝，实现对该病菌核萌发的有效抑制。在研究PDMS-b-PQAS对水稻纹枯病菌丝的抑制机理及其在模拟复杂固体表面的吸附与浸润特性的基础上，通过建立两亲性大分子季铵盐的结构及其在菌核表面的吸附与渗透特性、对菌核萌发的抑制作用三者之间的结构-性能关系，结合盆栽与田间试验，为探索水稻纹枯病的根治新方法提供理论依据。

Rhizoctonia solani is hard to be eradicated because it can resist the existing fungicides in the form of sclerotium. According to the asexual reproduction of R. solani, i.e., from mycelium to sclerotium and to mycelium again, and also the typical inner-outer layers structure of R. solani sclerotia, a novel amphiphilic macromolecular containing quaternary ammonium salt (PDMS-b-PQAS), with polydimethylsiloxane (PDMS) as the hydrophobic block, and polymers containing quaternary ammonium salt as hydrophilic block, was designed and synthesized. PDMS-b-PQAS could act as both macromolecular surfactant and macromolecular fungicides, thus it could stably absorb on the surface of sclerotia based on the hydrophilic-hydrophobic interaction, then the hydrophobic outer layer of the sclerotia were soaked and infiltrated by both water and the macromolecular surfactant, i.e., PDMS-b-PQAS, and the inner mycelium could be inhibited or destroyed by the infiltrated PDMS-b-PQAS, thus the R. solani sclerotia germination could be effectively inhibited. The core of this project including four parts, firstly, the inhibition effect of PDMS-b-PQAS on R. solani would be extensively studied; secondly, the relationship between polymer structure and adsorption/soaking characteristics on the complex surface of simulating solids would be established; and thirdly, the structure-properties relationship among PDMS-b-PQAS structure and its adsorption, soaking and infiltrating characteristics on the surface of the R. solani sclerotia, and the inhibition of sclerotium germination would be established; at last, a novel method for the eradication of rice sheath blight based on the above mentioned structure-properties relationship and the pot/field experiments would be carefully explored and put forward, which could also provide scientific evidences for the permanent prevention and control of rice sheath blight.