利用愈伤组织验证细菌分离物B619与松材线虫病的关系

用细菌分离物B619、无菌松材线虫以及它们的混合物接种黑松愈伤组织，发现无菌线虫或B619单独接种的黑松愈伤组织表现为轻微褐变；二混合接种的黑松愈伤组织严重褐变、萎缩、表现高度感病；而二得混合接种的预先用抗菌素处理的愈伤组织发病较轻。这些结果与接种黑松幼苗的结果相似，再次证明了松材线虫病是一种由松材线虫和细菌共同侵染引起的复合侵染病害。在愈伤组织中单独接种B619，接种后其数量逐渐下降，而在愈伤组织中混合接种，B619繁殖很快，其数量呈上升趋势，表明在愈伤组织内松材线虫的存在有利于B619的繁殖。

Experiments on the Relationship Between the Bacterium Isolate B619 and the Pine Wilt Disease by Using Calli of Pinus thunbergii

The calli of Pinus thunbergii were separately inocul ated under aseptic conditions with aseptic pine wood nematodesBursaphelenchu s xylophilus(Steiner & Buhrer)Nickle],bacterium isolate B619 isolated from t he virulent nematode,and mixture of both.It was found that the calli inoculated with the aseptic nematodes or bacterium isolate B619 became browning slightly,w hile those inoculated with the mixture of the aseptic nematodes and bacterium is olate B619 became browning and wilted severly.After inoculating with the mixture of the aseptic nematodes and bacterium isolate B619,the disease index of calli treated with certain antibiotics was lower than that of the control.Those result s further demonstrated that the pine wilt disease was a disease complex involvin g the nematodes and bacteria.Bacterium isolate B619 could hardly propagate in th e calli without nematodes but could quickly propagate in the calli inoculated wi th the mixture of the aseptic nematodes and bacterium isolate B619.This indicate d that the existing of nematodes in the calli was favorable for the propagation of bacterium isolate B619.