Comparative Studies On The Physiological And Biochemical Mechanisms Of Gueneefolder Resistance Of Goose Lake Fragrant Rice,dongxiang Wild Rice And Tsuen You 822

Oryza sativa is one of the important food crops for human beings and the basic guarantee for human reproduction.As one of the most serious insect pests,Cnaphalocrocis medinalis has a serious impact on the growth and yield of rice crops.At present,the control of C.medinalis is mainly by spraying pesticide.This method not only requires the concentration of pesticide itself and the spraying period,but also causes irreparable pollution such as soil and water resources.Therefore,it is of great strategic significance to cultivate O.sativa,which has tolerance to C.medinalis,ensure the yield and quality rice in the limited cultivated area.In recent years,the emergence of hybrid rice has solved the problems of high rice diseases and insect pests and low yield to some extent,but with the increase of planting algebra,hybrid rice has also exposed the weakening of resistance.Based on this,this paper to three different varieties of O.sativa,before and after pest of the leaf rate,soluble sugar,reducing sugar,free proline,malondialdehyde,chlorophyll,silicon,silicon size,oxidase（POD）,polyphenols oxidase（PPO）and Superoxide dismutase（SOD）enzyme activity was determined,mainly studied the resistance mechanism of O.sativa,to cultivate a high quality rice provides a new theoretical guidance.This study mainly includes the following three chapters:Chapter 2: Effect of Cnaphalocrocis medinalis on leaf roll rate and sugar content of different Oryza sativa varieties.In this chapter,the effect of Cnaphalocrocis medinalis on the leaf rolling rate of three kinds of O.sativa（Goose lake fragrant rice,Dongxiang wild rice and Tsuen You 822）was calculated under the exclusion of natural enemies,and determine the sugar content of different varieties of plants before and after feeding rice.The results showed that the rice feeding or parasitic Dongxiang wild rice was the lowest,the population trend index of Tsuen You 822 was the highest,and the Goose lake fragrant rice was in the middle.There were obvious differences between the soluble sugar varieties in rice plants before and after the C.medinalis pests,and the soluble sugar content and reduced sugar content of different varieties were reduced,but the decrease was different.So,the relationship between sugar content and insect resistance was preliminarily obtained,which laid a foundation for further studying the mechanism of physical and chemical resistance in different O.sativa varieties.Chapter 3: Effect of Cnaphalocrocis medinalis hazards on physiological and biochemical indexes of different Oryza sativaOn the basis of the above experiments,the size and content,the content of the silica layer,the content of the free proline,malondialdehyde and chlorophyll content physical and chemical indexes on the leaf of the three rice insect pests were determined.The results show that the Dongxiang wild rice was the highest silicon conten and twax layer content,and silicon chains are closely aligned which showed strong resistance;However,the silicon content,wax layer content and free proline on the leaf surface of Goose lake fragrant rice increased greatly after insect pests,and the content of malondialdehyde increased the least,which was manifested as a strong self-repair mechanism.In this chapter,the physical and chemical content of Goose lake fragrant rice,Dongxiang wild rice and Tsuen You 822 was analyzed,and further the resistance mechanism of the three rice was studied.Chapter 4: Effect of Cnaphalocrocis medinalis hazard on protective enzymes activity of different Oryza sativaThis chapter measures the activities of three main protective enzymes: peroxidase（POD）,superoxide dismutase（SOD）and polyphenol oxidase（POD）before and after pests of three kinds O.sativa.The results showed that the activity of superoxide dismutase（SOD）and polyphenol oxidase（POD）were the highest in the Dongxiang wild rice leaves,with strong resistance;after the pest,the activity of the three enzymes in the leaves of the Goose lake fragrant rice plants increased greatly,showing a strong repair mechanism.Tsuen You 822 has no pre-pest resistance or post-pest restoration capability.Analysis of the changes in the activity of the three enzymes,we further understand the resistance mechanism of the three O.sativa species.