Salt Tolerance Evaluation And Nitrogen Nutrition Physiology Research Of Chrysanthemum Morifolium

Chrysanthemi flos?Chrysanthemum morifolium Ramat.?is traditional crude drug for medicine and food.With the development of new products and the public attention to preserve one's health care in resent years,Chrysanthemi flos have brought in strong social demands.As its strong adaptability,Chrysanthemum are widely introduced in coastal and other inland areas to satisfy production requirements.But many of the areas are soil salinization,which will seriously affect the yield and quality of chrysanthemum.This study is foused on-the salt tolerance characteristics of Chrysanthemum morifolium,salt tolerance of some of the resources was evaluated,while carrying out physiological studies of nitrogen nutrition in order to provide some technical reference for the selection and the actual production of salt-tolerant varieties of Chrysanthemum.morifolium.Results are as follows:1.The experiment was conducted under controlled hydroponics to comprehensive evaluate the salt tolerance of Chrysanthemums morifolium as influenced by 40%artificial seawater in a laboratory at experimental station of Nanjing Agricultural University.Results:Biomass,Membrane Permeability,Activity of SOD and POD,Total soluble sugars,Pro and other indicators that can be used as indicators of the rapid evaluation of salt tolerance of Chrysanthemum morifolium.34?K1 and K2 are the excellent resource for salt-tolerance screening.Organ quality comparison study showed that the distribution of secondary metabolites in each cultivars of chrysanthemum flower organ of tubular flowers and ray florets are different.Chlorogenic acid contents are higher in the tubular flowers,while luteolin levels is higher in the ray florets.2.In vitro micropropagation and shoot regeneration,using leaves as explants,were studied in 3 species of K1,K2 and 34.The results showed that the media with NAA 0.1 mg·L^-1+6-BA 1.0 mg·L^-1+2,4-D1.0 mg·L^-1 are much better than others when callus were induced.While the MS medium with 6-BA 2.5 mg·L^-1+NAA 0.6 mg·L^-1 is the preferable medium for proliferation.The formation rate of leaves calli reduced by increase processing time as the same to increase EMS concentrations 0.4%concentration of EMS and 2 h treatment with Chrysanthemum morifolium leaves get the best result at semilethal dose.3.Low salinity treatments induced increase in the contents of Car,osmotic stress have greater influence on superoxide ion balance and membrane peroxidation than that of ion stress when concerned on Chrysanthemum morifolium;Effect of high concentration artificial seawater treatments on photosynthetic pigment have greater damage to C.morifolium 'huaiju' than that of Chrysanthemum morifolium;Under normal circumstances,the activity of SOD,POD,CAT in Chrysanthemum morifolium' is higher than that of C.morifolium 'huaiju'.Chrysanthemum morifolium' is likely to remain higher activity of antioxidant enzyme in response to stress when facing high salt stressChrysanthemum morifolium will accumulat more soluble protein and soluble sugar in response to high concentration of NaCl and isotonic PEG6000 stress;Artificial seawater treatments,Chrysanthemum morifolium will accumulate more soluble protein and proline when faced with low concentrations stress,while accumulate more soluble sugars in response to high concentration of artificial seawater stress;We believe that the actual contribution of osmotic regulation substances are proline>soluble sugar>soluble protein.The mechanism of ion regionalization are different when under NaCl,isotonic PEG6000 and artificial seawater stress.Under NaCl stress,Chrysanthemum morifolium will accumulate more K⁺ contents in roots,base of the stems and young leaves,more Ca²⁺contents in aged leaves,base of the stems and young leaves,reduce the absorption of Na⁺contents,increasing the contents of Mg²⁺ to cope with the stress at the same time;Under artificial seawater stress,Chrysanthemum morifolium will accumulate more K⁺ contents in roots,base of the stems and stem,more Ca²⁺ contents in base of the stems and young leaves,priority Na⁺ contents in the aged leaves and base of the stems to cope with stress;Chrysanthemum morifolium will accumulate more Na⁺ contents mainly depend on roots,base of the stems and young leaves,more K⁺ contents in aged leaves,young leaves and roots,more Ca²⁺ contents in roots,young leaves and base of the stems,higher leaf-root absorption selectivity SK.Na to ensure more K⁺ are transported to the blade to cope with isotonic PEG6000 stress.4.Effect of NaCl stress on photosynthesis of Chrysanthemum morifolium is the main cause by non-stomatal limitation factors.The increase of super oxygen anion,MDA content and the decline of relative water content may be largely influenced by Na⁺,while the damage to membrane permeability may be mainly influenced by Cl^-.The variation trend of antioxidant enzymes ordered by CAT,SOD,POD;The contents of soluble sugar,soluble protein and Pro are gradually increase with the concentrations stress level increasing.The changes trend of soluble sugar and soluble protein contents may be largely influenced by Na⁺,while the changes trend of Pro mainly influenced by Cl^-.5.Nitrogen form has remarkable influence on the photosynthesis,nitrogen metabolism,growth and quality,spot blight incidence,disease index and secondary metabolites.The content of chlorogenic acid and 3,5-O-dicoffeoylqunic acid are 0.673%and 1.838%respectively,reaching the maximum at the NH₄⁺-N/NO₃^--N ratio of 25:75;The content of luteoloside increasewith the ratio of NO₃^--N increasing and reached it's maximum at the NH₄⁺-N/NO₃^--N ratio of 0:100;The yield of Chrysanthemums morifolium reach it's maximum at the NH₄⁺-N/NO₃^--N ratio of 25:75.The spot blight incidence and disease index of Chrysanthemum morifolium are closely related to physiological indicators and secondary metabolites,The correlation analysis shows that lignin,total soluble sugars,the activity of PAL and POD,O2-,chlorogenic acid,3,5-O-double-caffeoyl quinic acid and total flavonoids of flowers are negatively correlated with the spot blight incidence and disease index,reaching a significant level of 0.01,while the SOD activity and MDA content are positively correlated with the spot blight incidence and disease index,reaching a significant level of 0.05.The spot blight incidence and disease index of Chrysanthemum morifolium decreased with the ratio of NO₃^--N decreasing,and reach the lowest level at the ratio of 25:75.