Studies On The Drought Stress And High Temperature Stress And Trace Elements Regulation Of Platycodon Grandiflorum(JACQ.)A.DC.

Platycodon grandiflorum is frequently-used medicinal plant,It was planted in most parts of our country,its root can be used to Xuanfei,Liyan,Expectorant,Pus and so on.According to the process of Platycodon grandiflorum seed germination usually occurs " fall dry " phenomenon,in an attempt to establish an efficient way to keeping soil moisture when the seeds are germinating in drought area.Finding the foliage spraying exogenous substances to alleviate the damage of Platycodon grandiflorum leaves are caused by the high temperature stress.according to the main cultivated areas of soil microelement deficiency status and studying Cu,B,Se,Mo 4 kinds of trace element fertilizers on yield and quality of Platycodon grandiflorum.1.The treatment of 1g SAP,1g SAP + 9 g Na bentonite,1.5 g SAP + 12 g Na bentonite,1 g SAP + 9 g Ca bentonite was beneficial to seed germination rate,root growth rate and increased leaf relative water content of platycodon grandiflorum,enhanced the activities of SOD and CAT,the contents of proline,contents of soluble polysaccharide and soluble protein,effectively reduced the damage of drought stress on cell membrance.At the same time,the exogenous substances increased the contents of chlorophyll and carotenoid,the efficiency of leaf photosynthesis,increase the ASA and GSH content,and thus effectively resist the oxidative stress caused by drought stress,but with the increasing concentration of spraying,Platycodon grandiflorum decreases the ability to resist drought stress.2.The treatment of 6 mmol·L-1 CaC12 and 1.5 mmol·L-1 SA enhance the activities of SOD and CAT,the contents of proline and soluble protein,and effectively reduce the damage of heat stress on cell membrance.At the same time,the exogenous Ca2+ and SA increase the contents of chlorophyll and carotenoid,the efficiency of leaf photosynthesis,increase the ASA and GSH content,and thus effectively resist the oxidative stress caused by high temperatures,but with the increasing concentration of spraying,the high treatment of CaCl2 and SA could decrease the ability to resist high temperature stress of Platycodon grandiflorum.3.Cu2+ could significantly improve the photosynthetic pigment content and net photosynthetic rate of Platycodon grandiflorum leaf.In the 150 mg·L-1Cu2+,Platycodon grandiflorum leaf MDA content was the lowest,the total flavonoid content of soluble protein,SOD,cat enzyme activity and root,polysaccharide and platycodin D content were the highest,and different concentration of Cu2+ on the root of Cu,Zn,Mn,Fe,Ca accumulation effect,but with the increase of the concentration of Cu2+,in the 250 mg·L-1,significantly reducd the photosynthetic pigment content.net photosynthetic rate,and the accumulation of platycodin D of Platycodon grandiflorum4.Under 150-200 mg·L-1MoO42-processing,the physiological and biochemical indexes in leaves of Platycodon grandiflorum and the content of effective components of roots of Platycodon grandiforum were the highest,it had a positive effect on nitrate reductase activity and amino acid content of Platycodon grandiflorum in plants,it could avoid excessive nitrite and cause harm to the human body,and different MoO42-cocentrations had significant effects on trace element concentrations in roots,but with the increase of M0O42-concentration,at 250 mg·L-1,it started to suppress the growth resulted of Platycodon grandiflorum.5.The treatment of 50-100 mg·L-1 BO33-was the best,under 50-100 mg·L-1 BO33-processing,the physiological and biochemical indexes in leaves of Platycodon grandiflorum and the content of effective components of roots of Platycodon grandiflorum were the highest,it had effect on promoting the growth of roots of Platycodon grandiflorum,enhancing Platycodon antioxidant enzymes and the activity of nitrate reductase,it affected the growth and metabolism of Platycodon grandiflorum,and different BO33-concentrations had significant effects on trace element concentrations in roots,but with the increase of BO33-concentration,in 150 mg-L-1 Platycodon blade has mild chlorosis,200 mg-L-1has a large area of yellow leaves of Platycodon grandiflorum,and obviously suppressed the growth resulted of Platycodon grandiflorum.6.SeO32-significantly increased the photosynthetic capacity of Platycodon grandiflorum leaves.The treatment of 10-15 mg·L-1 SeO32-was the best,the physiological and biochemical indexes in leaves of Platycodon grandiflorum and the content of effective components of roots of Platycodon grandiflorum were the best,it was promoting the cycling of nitrogen and amino acid content of Platycodon grandiflorum,at this time,the content of organic selenium was higher than that of inorganic selenium,it was conducive to the absorption of the human body,and different SeO32-concentrations had significant effects on trace element concentrations in roots,but with the increase of SeO32-concentration,In 25 mg·L-1,it started to suppress the growth resulted of Platycodon grandiflorum.7.The treatment of Se and S mix was no significant difference to the activities of SOD and CAT of Platycodon grandiflorum.In the low treatment of S(2 mmol·L-1+15 mg·L-1)significantly enhanced the photosynthetic capacity of Platycodon grandiflorum.Compared with CK,the S treatment(2 mmol·L-1)under the different concentration of Se treatment could improve the root length and root diameter,reduce the MDA content,increase the content of chlorophyll,promote the vitamin C and Platycodon grandiflorum polysaccharide content,the soluble protein content decreased when the increase of se concentration in low treatment of S(2 mmol·L-1),in the treatment(2 mmol·L-1+25 mmol·L-1)that organic.selenium content reached the maximum and the sulfur content was significantly lower than CK.Certain concentration of se and s fertilization significantly increased the content of Mineral element and reduced the accumulation of Fe,the accumulation of Ca was no significant effect of Platycodon grandiflorum roots.