| Soybean(Glycine max(L.). Merr) origins from China. It is an important crop serving as the major resource of edible oil and plant protein in the world. Soybean production in China could not satisfy the markets demands due to low yield and seriously harm of weeds. Therefore, a large number of glyphosate tolerant genetically modified(GM) soybeans were imported fro m abroad. Development of glyphosate tolerant soybean could improve weed control efficiency, reduce weed management cost,although the international trade of genetically modified soybeans has long been commercialized, but the problem of food safety of genetically modified soybeans have yet to be further verified.The glyphosate is an efficient, low toxicity, broad spectrum, conductive, no selective kind of herbicide.which developed by the United States of America Monsanto and has the epoch-making significance. Its market application can not only improve the agricultural productivity, brought great convenience for farmers, but also changed the direction of development of modern agriculture.The glyphosate could control most of weeds by absorbing from leaves and guide to the part of the plant. But because of its broad-spectrum and non-selective characteristics, it also has a toxic effect while killing weeds and crops. Glyphosate-resistanct crops, not only enable the glyphosate control weed effectively, but also improve labor productivity, reduce the planting cost,Glyphosate-resistant crops could effectively control weeds, increase laber productivity, decrease planting cost and protect crops from herbicide injury which had important economic values. Therefore, screening and excavating glyphosate-resistant germplasm played a vital roles in cultivating new herbicide-resistant varieties. In recent years, some researches screened glyphosate-resistant genes from resistant bacterials and transfered them into plants by using molecular biology techniques. But there were disadvantages of transformation and safety. Different crops had different resistance to herbicide. It was an effective method to screen resistant germplasm from different crops and applied host resistant genes into crops.Sreening and identification were different soybean resistace to glyphosate in this research using field trials. Target enzymes, protect enzymes and endogenous hormone have finished for analysis, sph-ysiological and biochemical mechanism to glyphosate is clear. The main findings of this study as follows:(1) The 100 soybean materials showed significantly different resistance levels after the application of 0.92 g ae ha-1 glyphosate application and acquire the resistant wild soybean germplasm,SD1. At different dosage and different years, SD1 is stable strain and high temperature has some effect.(2) Reaserch of resistance stability.The resistant material SD1 and susceptible materials Williams 82,ZH35 the shikimate accumulation and chlorophyll content were analyzed. At glyphosate application, there were no significant differences in shikimate levels and Chlorophyll content in SD1. But there have significant decrease in shikimate and chlorophyll content in Williams 82 and ZH35. Therefore, shikimate content no accumulation was a reason for physiological mechanism.(3) Soybean resistance to glyphosate physiological and biochemical mechanism analysis. Resistant wild soybean leaves after glyphosate stress, the leaves of SOD, POD showed decreased and then gradually,MDA content increased and then decreased. But SD1 continued to decrease. Therefore, Resistance strains were higher activity cleared reactive oxygen made of SD1. This factor is one of the reasons for the enhancement of the resistance of SD1, G STs and GSH activity was enhanced in SD1. |
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