Research On Promotion And Biocontrol Of Root-knot Disease On Medicinal Plants By Bio-fertilizer "NS"

In general,plant growth promoting rhizobacteria(PGPR)prevent plant diseases and promote the growth of plant by one or more mechanisms.Under the pressure of plant diseasas,PGPR can improve the disease resistance of plant,inhibit infection and expansion of pathogen through competition for nutrientions,colonization sit competition,inducing Systemic acquired resistance(SAR)and induced systemic resistance(ISR)or other methods.However,Some PGPR can directly promote the growth of plant in the absence of disease pressure.For instance,microorganisms may fix nitrogen,resolve phosphate or potassium,ultimately,providing plant with more nutritions.Or,they excrete plant hormones,such as auxin,cytokinin,gibberellin,to promote plant growth.The bio-fertilizer"Ning shield" is a production mixed with many PGPR,which the main effective composition is Bacillus.The early research shows that "NS" has a high biocontrol efficacy to bacterial wilt of tomato,cucumber root-knot nematodes,watermelon wilt,phytophthora capsici and other soil borne disease.The efficacy of growth promotion and production increasing in field is remarkable.Trichosanthes kirilowi Maxim.is an important medicinal resource,which is recorded in the previous versions of "People's Republic of China Pharmacopoeia".When its root,fruit and seed all can be medicine,the dry root of T.kirilowi used in medicine is called trichosanthin,with the efficacy of heating,Chesting and moistening.Dioscoree opposita Thunb.cv.Tiegun is the treasure of D.opposita which is famous for the "four pregnant drugs".Tiegun is an unique specie in Chinese yam germplasm,and it is said that "yam top in four pregnant drugs,Tiegun is the king in yam family".Modern science has proven that Tiegun could stomach,kidney,tonic,anti-hypoglycemic,prolong life and enhance immunity.The biggest problem in planting process of T.kirilowi and Tiegun is the serious harm of root-knot nematode(RKN)disease,which affects the crop growth and final yield,but also the impact of commodity properties and food value,resulting in a serious decline in the quality of medicines and farmers' income.Dendrobium officinale Kimura et Migo is a rare traditional Chinese medicinal herbs,known as the "Chinese immortality" and "gold in medicine".D.offcinale is the main species of Dendrobium sp.in the 2010 version of "Chinese Pharmacopoeia",which has the efficacy of nourishing yin and coughing,throating eyesight and prolonging life.With the rapid development of health industry,the difficuty in transplanting and the slow growth of D.officinale has become an important factor which restricts its industrial development.This study detected the growth promotion and biocontrol efficacy of RKN on T.kirilowii and Tiegun by bio-fertilizer "NS",and also the content of effective components.In order to screen the best concentration and method of"NS" in the vitro micropropagation system of D.officinale plantlets,The transplanting survival rate and growth index were statistical,and the quality of D.officinale was valuated later.The detail results are showed as follows:1.According to the results of the field tests in two years,the biocontrol efficacy of "NS"to RKN was about to 50%,when the population number in soil was reduced more than 60%.The seedling rate and the growth index were increased significantly by bio-fertilizer "NS",and the chlorophyll content was improved about 10%.The content of N,P,K and organic matter in soil were increased 22.27%?50.91%,respectively.The fresh weight of T.kirilowi was increased about to 20%,and the drying rate was significantly improved too.The content of polysaccharides and trichosanthin in T.kirilowi was increased 12.25%and 16.72%,respectively.2.The biocontrol efficacy to RKN on Tiegun by "NS" was about to 50%,reducing the occurrence of disease significantly.The length and diameter of Tiegun were improved significantly by "NS",the increasing leval was 26.39%and 18.54%,and the yield was increased 24.53%.The content of starch was increased more than 20%,and the total solid,protein,reducing sugar,and glycosaminoglycan were all increased about 10%.So it was that "NS" greatly improved the taste and nutrition value of Tiegun.3.The transplanting survival rate of D.officinale plantlets was significantly increased 16.77%?33.54%by different treatments of "NS",and the plant height,stem diameter and leaf number were also increased significantly.While the treatment that root diping and mixing with 2×10~7 CFU/mL of "NS" performed the best effect,the treatment which the concentration was 5×10~6 CFU/mL followed,but there was no significant difference between the two treatments.The content of polysaccharide and total alkaloid were increased 12.77%and 6.97%,respectively by 5×10~6 CFU/mL of "NS",so the medical quality was improved significantly.