松材线虫自然侵染后对不同松树组织结构的影响

Impact of pine wood nematode invasion on the micro-structures of different pine hosts

利用滑走切片技术从显微水平研究松材线虫(Bursaphelenchus xylophilus)在自然状态下入侵,对马尾松(Pinus massoniana)和黑松(Pinus thunbergii)显微结构的影响。结果表明,马尾松和黑松的组织结构在感病初期即表现出病变特征,并随感病时间推移病变加剧。马尾松在感病初期皮层薄壁细胞开始木质化,伴有细胞破裂并融合成空腔;至感病中期周皮的栓内层细胞、皮层薄壁细胞以及韧皮部薄壁细胞均发生木质化,细胞内含物增多,甚至形成层细胞也发生一定程度的木质化现象,树脂道因周围细胞破裂而变形;至感病晚期,木材以外所有部分完全被木质化、大量细胞破裂。黑松发病症状与马尾松大致相同但发病时间稍晚,发病程度也较轻,这可能是因为两者对松材线虫病的抗性强弱有差异。同一时期的组织病理学特征在空间上也存有差异,这与松材线虫入侵的位置及其在树体内的分布有关。

To study the impact of the pine wood nematode （PWN, Bursaphelenchus xylophilus） invasion on the micro-structures of Pinus rnassoniana and P. thunbergii , slicing section technology was used. The results indicated that the structures showed lesion characteristics during the early period of invasion and become aggravated with the time passed. For P. massoniana, parenchyma cells became lignified and cell rupture. During the second period of invasion, periderm cells, parenchyma cells of cortex and phloem all became lignified and their contents even cambial cells also became lignified. In the later period, all cells became lignified and lots of cells rupture. However, for P. thunbergii, pathogenic characteristics were the same as that of P. massoniana, but occured later and the disease degree was lighter, which indicated the difference of resistance to PWN between two pine trees. Histopathological features at the same stage were also different, it was related to the location of invasion and the distribution of PWN in the pine trees.