松材线虫与其伴生细菌在寄主内的种群动态

Population Dynamics of Pine Wood Nematode and its Accompanying Bacterium in the Host

利用马尾松水培离体松枝作接种材料 ,分别接种消毒后的松材线虫、松材线虫伴生细菌坚强芽孢杆菌和松材线虫与坚强芽孢杆菌的混合液 ,以研究松材线虫与其伴生细菌在松枝中的种群动态。结果表明 :松材线虫和坚强芽孢杆菌混合接种 ,松枝发病 ,松枝髓部发生褐变 ,褐变的过程是由接种枝发展到主枝 ,再由主枝下部向上部发展 ,而单独接种松材线虫或坚强芽孢杆菌 ,松枝不发病 ;松材线虫和坚强芽孢杆菌混合接种较单独接种松材线虫 ,松枝中的松材线虫繁殖量大、扩散速度快 ;松材线虫在松枝中扩散的过程是 :接种枝→主枝→侧枝→新梢 ,在主枝中由下部向上部扩散 ;松枝髓部褐变过程和松材线虫在松枝中扩散过程相一致 ,松材线虫扩散分布先行于髓部褐变 ;松材线虫和坚强芽孢杆菌混合接种较单独接种松材线虫或坚强芽孢杆菌初期 ,松枝中致病细菌的检测量大 ,从而提出细菌和松材线虫均是松材线虫病不可缺少的致病因素。文后指出寄主主干下部髓部褐变可用作病害的早期诊断。

year old aquacultural excised branches of Pinus massoniana were inoculated with disinfected Bursaphelenchus xylophilus(Bx), the bacterium Bacillus firmus(Bf) accompanying Bx and the mixture of Bx and Bf respectively in order to investigate the population dynamics of Bx and its accompanying bacterium in the branches. The results showed that by inoculation with the mixture of Bx and Bf, the branches were diseased, the pith of the branches browned, the process of pith browning was from inoculated branch to main branch, and from lower part to upper part in the main branch, while by inoculation with Bx or Bf singly, the branches were not diseased. By inoculation with the mixture of Bx and Bf than with Bx singly, the propagation number and moving speed of Bx in the branches were larger. The moving process of Bx in the branches were: inoculation branch→main branch→lateral branch→current shoot, and from lower part to upper part in the main branch. The process of pith browning showed no difference from the moving process of Bx in the branches, the distribution of Bx preceded the pith browning. At early stage after inoculation with the mixture of Bx and Bf than with Bx or Bf singly, the number of pathogenic bacterium detected in the branches was larger. Thus the standpoint was proposed that both bacterium and pine wood nematode was necessary pathogenic factor of pine wood nematode disease, and pith browning in lower part of the main stem of the host could be used for early diagnosis of the disease.