Effect Of Ginseng Rhizosphere Soil Extracts On Pathogenic Fungi And Their Antagonistic Microorganisms

Panax ginseng C. A. Meyer, is a perennial herb of Araliaceae family. The great value of P.ginseng gains increasing attention from the world over the years. However, the development ofP. ginseng industrialization is restricted by continuous cropping obstacle. The P. ginseng, whichis like other perennial root plants, could not be cropped continuously, as the roots of P. ginsengwould be burned, rotted and cause soil to be infected by the borne disease. The influence on thegrowth of ginseng pathogenic fungi, antagonistic bacterias and antagonistic actinomycetes wasstudied by examining the extracts of new forest soil, the ginseng rhizosphere soil for three yearsof continuous cropping and the ginseng-grown land soil for ten years of rest. It will providetheoretical basis for discussing the allelopathy of the P. ginseng rhizosphere secretion, andanalyzing the cause of P. ginseng continuous cropping obstacle and recycling the ginseng-grownland.First of all, new forest soil, the ginseng rhizosphere soil for three years of continuouscropping and the ginseng-grown land soil for ten years of rest were extracted by differentsolvents. The activity of extracts was tested by ginseng pathogenic fungi, antagonistic bacteriasand antagonistic actinomycetes. Inhibition rate was compared at last. The study has thefollowing findings:(1) The growth of pathogenic fungi and their antagonistic microorganismsare retrained by the extracts of P.ginseng rhizosphere soil on. Inhibitory activity: the ginsengrhizosphere soil for three years of continuous cropping> the ginseng-grown land soil for tenyears of rest> new forest soil.(2) The extracts that retrained the growth of the pathogenic fungiand the antagonistic actinomycetes exist in the low polarity position, and the extracts thatretrained the growth of pathogenic fungi exist in the middle and high polarity position.(3) Onthe whole, P. ginseng rhizosphere secretions restrain the growth of antagonistic bacterias themost, and restrain the growth of antagonistic actinomycetes weaker, and restrain the growth ofpathogenic fungi the weakest. It shows that the growth of benificial bacterias which is retrainedby extracts of P.ginseng rhizosphere soil is closely related to the outbreak of disease.(4)Thetype and content of fatty acids in the ginseng rhizosphere soil for three years of continuouscropping and the ginseng-grown land soil for ten years of rest is more than that in new forestsoil, while the type and content of saccharides in the ginseng rhizosphere soil for three years of continuous cropping and the ginseng-grown land soil for ten years of rest are less than that innew forest soil. In the cultivation soil of P.ginseng, the decrease of benificial bacterias ofP.ginseng is closely related to soil acidification.