Effects Of Zinc Sulfate Application On The Growth And Physiological Characteristics Of Platycodon Grandifloru

In this study,platycodon grandiflorus（Jacq.）A.DIC is used as the material to evaluate the yield,quality and economic benefit of platycodon grandiflorus.This paper studied the effects of zinc fertilizer on the morphological and physiological indexes of platycodon grandiflorum under the condition of applying zinc fertilizer to the soil and spraying ZnSO₄on the leaf surface of platycodon grandiflorum biennial,analyzed the changes of morphological and physiological indexes of platycodon grandiflorum,and obtained the optimal concentration for the growth and development of platycodon grandiflorum.The results are as follows:1.For annual platycodon grandiflorum,Zn2 fertilizer significantly increased plant height and stem diameter.Spraying ZnSO₄on leaf surface of biennial platycodon grandiflorum significantly increased plant height,stem diameter and leaf area.Foliar spraying ZnSO₄could promote photosynthesis and increase chlorophyll and carotenoid contents.With the increase of ZnSO₄concentration,the chlorophyll and carotenoid contents of Zn5 were higher than other concentrations.2.Applying zinc fertilizer to annual platycodon grandiflorum soil significantly,Zn2increased root length and root diameter.Spraying different concentrations of ZnSO₄on leaves had no obvious effect on root length of biennial platycodon grandiflorum,but Zn5 significantly increased root diameter.The number of root fractions determines the value of the product.The smaller the number of root fractions,the better the sales volume and the higher the value of the product.The Zn5 root fractions are the least,which helps to restrain the root fractions of platycodon grandiflorum and improve the value of the product.3.The effects of Zn3 and Zn5 on the soluble sugar content were different.The effects of Zn3and Zn5 on the soluble sugar content were not obvious in the other treatment groups.With the growth of the plantlet,the soluble sugar content in the leaves showed a decreasing trend.4.Spraying different concentrations of ZnSO₄on platycodon grandiflorum,Zn5significantly increased the soluble protein content in roots,and the soluble protein content showed a trend of increasing first and then decreasing,while the soluble protein content in leaves had no obvious change rule with the increase of concentration.5.The activities of POD,SOD,CAT and MDA were affected by spraying ZnSO₄with different concentrations.After spraying for 45 days,except for Zn1 and Zn2,the activities of POD and CAT Zn4 and Zn5 were significantly higher than those of the control group.The activities of POD,SOD and CAT increased firstly and then decreased with the increase of the concentration and the number of spraying days,while the content of MDA decreased with the growth of plants.6.The fresh weight of radix grandiflorum showed an increasing trend.The fresh weight of radix grandiflorum in six treatment groups was higher than that in the control group（Zn5>Zn6>Zn4>Zn3>Zn2>Zn1>CK）,and Zn5 increased the most by 76.6%compared with the control group.With the increase of ZnSO₄concentration,the root-shoot ratio increased firstly and then decreased,and Zn5 increased by 33.3%compared with CK.In conclusion,zinc fertilizer can increase plant height,stem diameter,root length and root diameter of platycodon grandiflorum.Spraying suitable concentration of ZnSO₄can increase the characteristics of plant height,stem diameter,leaf area and root weight,is beneficial to dry matter accumulation,improve the characteristics of economic value,increase the biomass,increase the chlorophyll and carotenoid content,improve the content of soluble sugar,soluble protein content,POD,SOD,CAT activity,lower MDA content and increase the resistance of platycodon grandiflorum.