【摘要】 通过对桉树无性系剪根苗接种青枯菌Ralstonia solanacearum 2个菌株后测定菌株的致病性、茎内的细菌数量得到,两菌株具有明显的致病性分化,强致病性菌株在剪根苗基部、中、上部的细菌数量都显著高于弱致病性菌株;2个菌株的细菌数量从茎基部到上部呈逐渐降低的趋势,木质部的含菌量比韧皮部高。通过提取和测定2个菌株胞外多糖(EPS)产量得到,强致病性菌株EPS的总产量及单个细菌EPS产量都高于弱致病性菌株。试验揭示青枯菌菌株的致病性分化与其在桉苗茎内的增殖扩散数量及其EPS的产量有着一定联系。更多还原

【Abstract】 By measuring the pathogenicity of bacteria and the number of bacteria in stems of eucalyptus clone cuttings after inoculation with two isolates of Ralstonia solanacearum,significant differentiation was found in pathogenicity between two isolates.The bacteria of the isolate with high pathogenicity in the basal,middle and upper portions of stems were significantly more than those of the isolate with low pathogenicity.For both isolates,the number of bacteria decreased gradually from base to top and bacteria in xylem was significantly more than those in phloem.By extracting and measuring extrapolysaccharide(EPS) produced by two isolates,it was found that both the total production and unit production of EPS of the isolate with high pathogenicity were higher than those of isolate with low pathogenicity.It was suggested in this experiment that the differentiation in pathogenicity of R.solanacearum isolates was associated with the propagation and spread of the bacteria in eucalyptus stem,and amount of EPS production of the isolates.更多还原