The Interaction Of Copper And Glyphosate In The Soil And Their Toxic Effects On The Wheat

As the industrial and agricultural development,more and more pollutions went into the environment and coexistenced.Many environmental effects of pollutions could not be explained use the mechanism of a single pollution.The combined polltion has gradually become an important direction of scientific development.In summing up the thesis of combined pollution study at home and abroad,this thesis's major contents were:The glyphosate adsorption and desorption in several different characteristic soils by balance method,the glyphosate adsorption in the clay minerals and the impact of pH;The impact of copper on glyphosate absorption in the soils and clay minerals;The copper adsorption and desorption in several clay minerals,the copper adsorption with the impact of pH or glyphosate;The activity of soil enzyme,wheat germination,sprout length and root elongation under the combined pollution of Cu and glyphosate.Its main findings are as follows:1.The adsorption of glyphosate in several soils was investigated.The results indicated that the adsorption isotherms were well fitted with Freundlich equations.The adsorption quantities of glyphosate in soils were related to soil characteristics,which increased with increasing clay content,ferric oxide content and decreasing with soil pH,and it did not matter with the CEC.The adsorption quantities of glyphosate in soils followed the order of red Soil＞yellow cinnamon soil＞fluvo-aquic＞indicoticblack;in clay minerals,followed the order of Ca-montmorillonite＞zeolite＞kaolinite.We further studied the adsorption of glyphosate under different pH conditions.2.We had studied the adsorption of glyphosate in several soils and clay minerals under the effects of Cu.The results indicated that the adsorption isotherms were well fitted with Freundlich equations.The glyphosate adsorption quantity in yellow cinnamon soil, fluvo-aquic and Ca-montmorillonite was decreased while in zeolite and kaolinite were increased under the impacted of Cu.3.The experiment carried on the Cu adsorption in clay minerals under the impacted of glyphosate.The result show that the adsorption quantities of Cu were increased with increasing concentration of Cu,and it could well fitted with Freundlich equations.The adsorption quantities of Cu followed the order of zeolite＞kaolinite＞Ca-montmorillonite, and the adsorption quantity by zeolite and kaolinite were decreased while it was increased by Ca-montmorillonite under the impacted of glyphosate. 4.The effects of both single and combined pollution of Cu and glyphosate on the activities of amylase,urease,phosphatase and catalase in paddy soil were studied under laboratory incubation condition.The results showed that there existed significant differences in effects of between single and combined pollution on soil enzyme activity. When the soils were treated with Cu,the activities of amylase,urease and phosphatase were inhibited;the catalase activity was stimulated with low concentration of Cu while inhibited with high concentration of Cu.When the soils were treated with glyphosate,the activities of amylase and urease were stimulated,the activity of catalase was inhibited,and phosphatase activity was stimulated at low concentration of glyphosate while inhibited at high concentration of glyphosate.It was found that there was a significantly interaction between Cu and glyphosate in case of combined pollution.The toxicity effect on catalase activity followed the order of combined pollution of Cu and glyphosate＞glyphosate＞Cu. The toxicity effects on the activities of amylase,urease and phosphatase followed the order: Cu＞combined pollution of Cu and glyphosate＞glyphosate.Analysis of variance also indicated that there were significant differences in soil enzyme activities in the contents of Cu or glyphosate(P＜0.01).Between the interaction of Cu and glyphosate,the differences of amylase and urease were extremely significant,and the difference of phosphatase and catalase were not significant.5.Through the toxicity test to wheat by glyphosate interaction with Cu,we found glyphosate's toxicity was greater than Cu on wheat germination rate.Whether Cu or glyphosate greatly inhibited the growth of the wheat roots and shoots,Cu's toxicity was greater than glyphosate on wheat roots,shoots was the opposite.Low concentrations of Cu decreased the toxicity of glyphosate to wheat germination rate while high concentrations of Cu increased its toxicity.To roots of wheat,the presence of Cu increased the toxicity of glyphosate,with the increasing concentration of Cu,the combined pollution increased inhibition to wheat roots;to shoots of wheat,the Cu significantly reduced the inhibition of glyphosate to wheat shoots,but with the increasing concentration of Cu,the combined pollution decreased inhibition to wheat shoots,but compared with glyphosate alone,its increased the wheat shoots to some extent.