Analysis Of Antibacterial Activity Of Chinese Herbal Extract And Their Prevention And Control Effect On Kiwifruit Canker

Kiwifruit industry has become one of the pillars of poverty alleviation in some areas of Hunan Province,but due to the influence of canker disease,hindered the rapid development of the industry.In order to effectively and pollution-free control of kiwifruit canker disease,improve the quality and safety level of kiwifruit,reduce the harm of canker disease on kiwifruit orchard.The purpose of this research is to improve the disease resistance of kiwifruit tree body,inhibit the growth and reproduction of kiwifruit ulcer bacteria,so as to reduce the incidence of tree body and improve the economic benefits of the industry under the premise of green health,high efficiency and practicality.This paper mainly studied the field investigation,the isolation and identification of the pathogen of kiwifruit canker,the screening of Chinese herbal bacteriostatic agent,the extraction technology of Chinese herbal bacteriostatic substance,the synergistic bacteriostasis of the complex,the bacteriostasis mechanism of the extracted complex,and the bacteriostasis control effect in the field,etc.The research results are as follows:(1)Isolation and identification of pathogen of kiwifruit canker.From kiwi canker disease tissue isolated pathogens isolates,after by Koch’s postulation,combination of isolates morphological observation and molecular identification,pathogenic bacterium to determine the cause of hunan province kiwi canker outbreak of clove false form bacillus kiwi pathogenic bacteria(P.syringae pv.actinidiae)of a kind.By measuring the physicochemical properties of the pathogen,it was found that fructan and ammonia could be produced in the process of physiological metabolism,without fluorescent pigment,without ice nuclear activity,without oxidase,starch hydrolase and arginine hydrolase,and catalase was contained.(2)Screening and analysis of bacteriostatic medicinal materials of plant origin of pathogenic bacteria.Eighty kinds of extracts of Chinese herbal plants with antibacterial effect were selected to determine their inhibitory effect on pathogenic bacteria by the Oxford cup method.The extracts of Chinese herbal plants with strong antibacterial effect were selected.Under the condition of 1.0 g/m L mass concentration of the extract of the tested Chinese herbal medicine,Acetone extracts of Scutellaria baicalensis,Syzygium aromaticum,Acorus tatarinowiiz and Pogostemon cablin all showed good antibacterial effect against Actinidia ulcerans with diameter of more than 20 mm.Scutellaria baicalensis had the best antibacterial effect,and the minimum inhibitory concentration was very low,only 3.90 mg/m L.All the extracts contained flavonoids,essential oils and saponins.(3)The extraction technology conditions and action conditions of the antibacterial active substances from Acorus tatarinowii and the synergistic antibacterial effects of the compound of Chinese medicine were determined.Through the Acorus tatarinowii extract single factor tests and response surface test,determine the bacteriostatic effect and the relationship between various factors and extract the better technology conditions as follows:ethanol concentration of 81.171%,extraction temperature of 54.730 ℃,solid-liquid ratio of 1:25,extraction time of 2 h,ultrasonic power of 700 W.Under these conditions,the diameter of the inhibition zone could reach 27.81 mm,and the best Acorus tatarinowii extract was stored in low temperature and away from light.The results of stability test showed that the extract of Acorus tatarinowii was suitable for low temperature and protected from light,but had poor effect under alkaline conditions.The synergistic antibacterial effect of the complex was analyzed by response surface analysis.The optimal formulation of the compound antibacterial agent was as follows: Scutellaria baicalensis: Acorus tatarinowii: Allium sativum: Pogostemon cablin: paeonia suffruticosa: Syzygium aromaticum= 182.310: 306.104: 521.432: 453.106: 153.199: 362.565.Under these conditions,the diameter of inhibition ring measured by the 1.0 g/m L compound could reach 33.860 mm in the actual test.It has better bacteriostatic effect than any single Chinese herbal extract.(4)Study on the antibacterial mechanism of Chinese medicine compound on the pathogen of kiwifruit canker.Through determination of traditional Chinese medicine compound content of extract of kiwi canker pathogen bacteriostatic(MIC)and minimum bactericidal concentration(MBC),after depicting the comparison function of bacterial growth curve,combined with traditional Chinese medicine(TCM)of bacteria cell wall,cell membrane,the influence of intracellular nucleic acid analysis,and assisted by electron microscopy,tem to observe changes of shape and structure of bacteria,comprehensive analysis shows that the traditional Chinese medicine compound with content can reduce the bacteria’s life activity,make it grow slowly;Destroy the cell wall and cell membrane,so that the material inside the cell outflow;Affect the morphology and structure of the bacteria,making the bacteria twisted and deformed;Reduce the content of DNA in the bacteria,so that the bacteria can not grow and reproduce normally.(5)The results of field experiments showed that the Chinese herbal compound showed good control effect by means of pesticide spray,daub and root irrigation.By spray method,the cure rate of 100 times dilution solution of Chinese medicine compound on canker spots reached 69.57%.The cure rate of 100 times diluent was as high as 79.17% by smearing method.The results of root irrigation showed that the disease index of orchard was only 11.38 after the application of Chinese herbal compound,which was better than the control effect of 20% clothiaocutum and rapiomycin commonly used in production.