| As a traditional Chinese medicine treating cough and sore throat,the market demand for Platycodon grandiflorum have increased year by year.High yield and quality of P.grandiflorum in Fujian is important to meet the market demand.In order to improve seed germination rate and solve the problem of low germination rate in field cultivation,the biological characteristics of 3 kinds of P.grandiflorum and optimum condition of thire seed germination were investigated in this study.Through management of fertilizer and the field density,the accumulation of active constituents and the change of physiological characteristics of P.grandiflorum were analyzed to determinate the suitable type,nutrient ratio of fertilizer and planting density.The present study may provide a theoretical basis for the key technique system of P.Grandiflorum cultivation.The main results were as follows:Effects of different soaking agents and water temperature on the seed germination of 3 kinds of P.grandiflorum seeds.The results of different inducers(CaCl2,H2O2,PEG6000,KMnO4,and H2O)treatment of P.grandiflorum seeds showed that PEG6000,KMnO4 and CaCl2 significantly improved the germination energy,germination rate,germination index of P.Grandiflorum seed.And results of the hot water treatment of seeds showed that the highest germination,germination rate and germination index of three varieties of P.grandiflorum seeds(Anguo,Bozhou and Chifeng)were observed at 30 degree of water temperature.2.Effect of different fertilizer proportions on physiological characteristics of 3 kinds of P.grandiflorumA).Effect of different fertilizer proportions on growth characteristic of 3 kinds of P.grandiflorumNitrogen(N),phosphorus(P)and the appropriate ratio of nitrogen to phosphorous(N/P)were conducive to root length of Anguo P.Grandiflorum,(APG)and stem gowth was promted by phosphoru.Bozhou P.Grandiflorum(BPG)required P treatment with high level,while mixed N and P with equal proportions showed benefit to gowth of root and stems.The increment of N was conducive to the gowth of root and stem of Chifeng P.Grandiflorum(CPG).B)Effect of different fertilizer proportion on physiological property of 3 kinds of P.grandiflorumThe contents of Chlorophyll,Photosynthetic rate of 3 kinds of P.Grandiflorum were all raised by the mixture of N and P that also increased the activities of protective enzymes,the activity of catalase(CAT),superoxide dismutase(SOD)and peroxidase(POD)in BPG were higher than those in other two kinds.C)Effect of different fertilizer proportion on the absorption of nitrogen,phosphorus and potassium in 3 kinds of P.GrandiflorumThe mixture of N and P was conducive to the absorption of N,P and potassium(K)in P.Grandiflorum,and the absorbed dose of BPG was highest.For APG,the N accumulated in leaves and stem under the combined applying of N and P.With the use increase of N fertilizer,N,P and K were accumulated in root,stem and leaves respectively.With the increase of P fertilizer,P was accumulated in root.For BPG,N and K were accumulated in leaves under all treatment,while P was accumulated in stem.For CPG,N and K were accumulated in root with an appropriate N/P.Nitrogen was accumulated in leaves and stem with a single treatment of N or P,and K was mainly accumulated in leaves with all treatment.D)Effect of different fertilizer proportion on quality in 3 kinds of P.grandiflorumThe effect of P on the dry substance accumulation in APG was most significantly.The dry substance accumulation in BPG was sensitive with single element,especially N.The combined applying of N and P had significant effect to the dry matter accumulation in CPG.The highest total protein contents of three cultivars of P.grandiflorum were obtained by treatment with N2P3 which promoted the contents of soluble sugar of APG and CPG as well as the contents of total saponins of BPG and CPG most significantly.And when the treatment with the N/P at 1,the content of soluble sugar was the highest in BPG,and the content of total saponins was the highest in APG.Based on the analysis of appearance and quality,BPG was most suitable for cultivation in Fujian area for it’s certain advantages such as less branches,high yield and goods value.3.Effect of different planting density on the physiological characteristics characteristic of BPGA)Effect of different planting density on the growth characteristic of BPGThe M3(8cm*25cm)treatment was most conducive to growth form of BPG compared to other treatments,and dry and fresh weight of plants reached the maximum in the middle and later period of growth.B)Effect of different planting density on physiological property of BPGThe M5(12cm*25cm)treatment had obvious effects on the activity of SOD and POD in BPG while the M2(6cm*12cm)treatment was beneficial to activity of CAT in BPG.The activity of protective enzyme under all treatments showed a declining trend after rising first,and then achieved peak when fruits were matured.Photosynthetic rate increased with the increase of planting distance,which reached the highest with M5 and followed by M4(10cm*25cm)treatment.C)Effect of different planting densities on the absorption of nitrogen,phosphorus and potassium of BPG.The N,P and K in BPG were mainly concentrated in stem and leaves during early growth,which gradually transferred to the roots at the late period.M1(4cm*25cm)and M4 treatment contributed to the N absorption,while M3 treatment ingnificanty increased the absorption of P and K.D)Effect of different planting density on yield and quality of BPGWith the M3 treatment,the dry substance accumulation was highest in BPG at later of growth which distributied uniformly in each organ.In BPG,the accumulation of total protein was promted by M2 treatment and M3 treatment.Also,M3 treatment had significant effet on the accumulation of soluble sugar.The total saponins accumulation was highest with M4 treantment,follwed by M5 treatment and M3 treatment.Overall,taking the yield and quality into consideration,M3 was selected as the best planting density,which recommended that BPG could be plated with the density of 33333 plants per mu. |
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