Development Of Multifunctional Seedling Substrate For Astragalus Membranaceus Var. Mongholicus To Promote Growth And Control Disease

The Astragalus membranaceus var.mongholicus(AMM)is a commonly used traditional Chinese medicine.AMM is a mainstream commodity in the market in China.Currently,transplanted AMM occupies major share of the AMM market,but it faces many difficulties and challenges in its cultivation and production:(1)the root rot of AMM has seriously occurred in many plant regions;(2)the contents of certain medicinal component in transplanted AMM do reduce compared with wild-simulated AMM;(3)stronger seedlings are needed when the AMM was transplanted;(4)the natural germination rate of AMM seeds is very low.Functional seedling substrates have the advantages of promoting crop growth,reducing the incidence of disease,and promoting seed germination.For these phenomena,the functional seedling substrates were developed and their application potential were evaluated for the large-scale cultivation and production of AMM.In the paper,the functional seedling substrates were prepared using Bacillus spp.as the functional bacterium and industrial waste in Shanxi province such as wine residue,vinegar residue,cow dung and biogas residue.The main results in the study are as follows:1.Based on determination of the ability of promoting plant growth,inhibiting effect to the pathogen causing root rot and compatibility among the test Bacillus strains in vitro,the target functional strains including G10,R91 and R57 were selected by the quantitative assignment method and fuzzy evaluation method.The optimal functional flora G10+R91and G10+R57 were obtained by measuring the inhibition effect of mixed fermentation.The functional Bacillus carriers were prepared using bran,peanut oil residue,corn flour and soybean flour.Then,the functional Bacillus fillers of the flora G10+R91,named FD5-G9(bran: soybean flour=5:1)and FH5-G9(bran: peanut oil residue=5:1)respectively,were selected based the CFU of G10 and R91 in the PDA plate.2.The organic-composite substrates were prepared using wine residue and vinegar residue as main materials and cow dung and biogas residue as auxiliary materials,and their physicochemical properties were tested.The organic-composite substrates E3(Vinasse residue Ⅱ: cow dung=2:1)and E2(Vinasse residue Ⅱ: cow dung=3:1)were obtained by fuzzy evaluation method for their higher content of nutrients,affordable and easily accessible.3.The mixed seedling substrates T1 and T2 were prepared by mixing the organiccomposite substrates E2 and F2(Vinasse Ⅱ: biogas residue=3:1)with garden soil,considering the principle of ease-to-use and economic.In order to investigate the effect of organic-composite substrates prepared with different auxiliary materials on the growth of AMM,the organic-composite substrate F2 also was selected as research target.The physical and chemical properties of mixed seedling substrates T1 and T2 were tested and the results helped to clarify their usability as substrates for AMM seedlings.4.Functional seedling substrates T1 P and T2 P were prepared by mixing functional Bacillus fillers and mixed seedling substrates.The effects of functional seedling substrate on seed germination and seedling growth of AMM were studied by the pot experiment.The results showed that T2 P increased the germination rate of AMM seeds by 53.67%,enhanced the vigor index and germination potential of seeds,and had obvious promotion effect on the biomass of AMM seedlings.5.The effects of functional seedling substrate T2 P and T1 P on the growth and pharmacodynamics components were studied by the pot experiment.The results showed that T2 P and T1 P generally increased the biomass and the contents of main pharmacodynamic components in healthy AMM seedling compared with the control.The contents of total flavonoid and total saponin in AMM,planted in the functional seedling substrate T2 P,increased by 90.91% and 537.71% respectively.The content of total polysaccharide in AMM planted in T1 P,increased by 48.39%.The functional seedling substrate T2 P had a better growth-promoting effect on AMM than T1 P.6.The biomass and content of pharmacodynamic component in AMM inoculated with the pathogen causing root rot were significantly affected by the functional seedling substrates.The incidence rate of AMM root rot was reduced by functional seedling substrates.Compared with the control,the survival rates and the growth of transplanted AMM inoculated the pathogens were increased by functional seedling substrate T1 P and T2 P.The above-ground plant height of AMM seedling planted in T1 P and T2 P increased by66.17% and 31.09%,respectively.The contents of total flavonoids and total saponins in AMM planted T2 P increased by 14.49% and 144.15% compared with the control,respectively.T1 P could significantly decrease the disease severity of root rot,with 49.00%control effect.T1 P showed better control effect on AMM root rot than T2 P.