The Responses Of Physiological And Biochemical In Walnut Leaves To Differrent PH

Based on the current re-cultivation of large-scale tea gardens in Ya'an area,as the severe acidification of the soil in this area is a serious problem,the article is going to clarify the key problems of walnut seedlings reaction mechanism and tolerance to soil acid stress in the region,and at the same time lay a good job for soil improvement.In this study,by studying pot culture,dynamic sampling and indoor treatment,the physiological and biochemical characteristics of walnut seedlings in two typical tea soils,and analyzing the characteristics of plant height,ground diameter,chlorophyll,photosynthetic rate,electrical conductivity,proline,soluble sugar content,SOD activity,POD activity,CAT activity,MDA content,etc.the following main conclusions are obtained:1)In the three sampling seasons,under different pH levels and based on different six soil treatments,plant height and ground diameter of walnut seedlings increased in different degree.There was no significant difference in plant height and ground diameter under different pH conditions in each soil,and there was no significant difference between the two soils.It indicated that walnut seedlings could grow normally in acid purple soil and yellow soil with different pH.2)The chlorophyll content of walnut seedlings in three sampling seasons was not significantly different under the different pH values of the two different soils.When the acid purple soil pH is 4.6 and the yellow soil pH is 4.1,the walnut seedlings can use light energy more effectively under strong light.It indicated that in the acid stress environment,walnut seedlings can perform normal photosynthesis.3)The proline of walnut leaves generally decreased with the increase of soil pH.The content of soluble sugar in the acid purple soil increased first and then decreased,reaching the highest point at pH 4.8-5.4;the yellow soil is slightly increased wavy.When the soil pH is 5.3-5.4,the relative conductivity is relatively higher than the rest of the pH conditions.In summary,when the pH of the walnut seedlings is 5.7 in the acid purple soil and the pH is 7.0 in the yellow soil,the osmotic adjustment tends to be stable.4)The antioxidant enzymes and MDA content of walnut leaves shows: SOD activity decreased slightly with the increase of pH value,and the POD activity decreased gradually with the increase of pH in acidic purple soil.In yellow soil,SOD activity increased with the pH value increased slightly in a wave shape,pH 5.3 was the bottom and pH 7.5 was the peak;with the increase of pH,POD activity decreased first and then increased,and then peaked at pH 7.5.The CAT activity of walnut leaves increased gradually with the increase of soil pH in the two soils,and reached a peak at pH 6.8(purple soil)or 7.5(yellow soil).The overall trend of MDA content in acid purple soil increased first and then decreased with the increase of pH;the content yellow soil first increased slightly and then decreased,and the content at pH 5.3 in was slightly higher than the other pH treatment.According to the data of three antioxidant enzyme activities and MDA content,the antioxidant enzyme system of walnut seedlings was more stable and efficient in acid purple soil pH 5.7 and yellow soil pH 7.5 than other situations.In summary,the walnut seedlings grow normally under strong acid stress and carry out photosynthesis,which has certain acid resistance.The difference of partial osmotic adjustment characteristics and antioxidant enzyme activities conditions reflected that walnut seedlings were more suitable for growth in weak acid or neutral soil under different pH.Acidic purple soil and yellow soil are suitable for the improvement of 2CaO level in the experiment.