ABSTRACT
This article was aimed to study the dynamics of biocontrol endobacteria in roots, stems and leaves of Panax ginseng and soils adjacent roots. Gradient screening and root irrigation methods were used to develop Rif-resistance bacteria and inoculation. Dilution plate method was used to count the number of them in roots, stems and leaves of P. ginseng and soils adjacent roots. The results showed that bacteria which can endure 120 μg·mL-1 Rif was developed, and no change was found on their antagonistic activity against A lternaria panax Whetz and Phytophthora cactorum. In roots and stems of P. ginseng, ge15 and ge25 showed the highest number in the initial.Then, populations of ge15 and ge25 in ginseng roots and stems decreased to a stable status gradually. In ginseng leaves, populations of ge15 and ge25 increased to the highest 3 days after inoculation, then, populations of them were decreased and kept at certain concentration. In ginseng rhizosphere soil, populations of ge15 showed reciprocating change, and which of ge25 showed increase initial, and then decrease to a stable status. It was concluded that endobacteria can keep a certain population in ginseng roots, stems, and leaves. Biocontrol agents based on them will be helpful for ginseng diseases controlling in the field.
ABSTRACT
By nutrient solution culture method, effects of benzoic acid, diisobutyl phthalate, diisobutyl succinate, palmitic acid, 2,2-bis(4-hydroxyphenyl) propane on root exudates of Panax ginseng were studied. GC-MS results in-dicated that, 15 to 23 components were detected in treatments including control, which were organic acids, alcohol, amino acid esters, phenols, amines, condensed nucleus, saccharine, etc. Through compared with control we found that, phenol and phenolic acids in root exudates increased in most of stress treatments. So we deduced that, the re-laxation of autotoxins from roots to outside environment was stimulated by autotoxins released into soil, and which ac-celerated the autotoxicity to ginseng seedlings.