杨树与栅锈菌互作的细胞学研究

CYTOLOGICAL STUDIES ON THE HOST-PATHOGEN RELATIONSHIP IN THE COURSE OF POPLAR LEAF INFECTION BY MELAMPSORA LARICI-POPULINA

利用生物电镜技术对落叶松—杨栅锈菌 (M .larici populina)与不同杨树无性系互作过程中的细胞学进行了研究 ,结果表明 ,在不同的非亲和性组合中 ,病菌侵染结构的受抑情况不同 ,主要表现为菌体内出现颗粒状物质和多聚核糖体 ,细胞紊乱程度增加 ,原生质解体 ;乳突、胼胝质的形成 ;吸器畸形及外包被物和管状复合物体的出现。寄主细胞对病原菌入侵的反应因品种而异 ,菌丝在寄主细胞间隙或沿寄主细胞壁延伸时 ,感病品种的叶肉细胞保持正常状态。抗病组合中 ,与菌丝接触部位的寄主细胞壁明显增厚 ,并产生乳突 ,细胞壁与质膜之间出现黑色沉积物 ;寄主细胞分泌电子致密度不同的物质包围吸器 ,同时细胞器与吸器相伴随 ,并向吸器周围聚集 ;叶绿体畸形 ,淀粉粒肿胀 ,最后消失 ;质膜内陷发生质壁分离 ,液泡膜上沉积大量的深色颗粒状物 ;细胞膜破裂 ,染色加深 ;细胞质紊乱 ,细胞器解体 ,细胞颗粒化或空泡化而坏死。中抗品种的细胞解体后 ,与受侵细胞相邻的寄主细胞仍很正常 ;高抗与近免疫品种的受侵细胞解体、坏死后 ,相邻的细胞也发生解体或坏死。

The cytology of interactions between poplar cultivars and leaf rust (Melampsora larici populina Kleb.)with different compatibilities were observed using electron microscopy at various times after inoculation. The results are as follows:(1) In non compatible combination, the infection structure of the hypha was restrained in different ways. In medium resistant species or hybrids with the hypha were slightly restrained, and the extending area was relatively large. As compared with susceptible species, there were more vacuoles and lipid body in the hypha, and the hypha became more the electron dense. Species or hybrids with a high ability of resistant were similar to the medium resistant ones, but the number of hypha was smaller with more hypha deformity, darker in electron dense. Compare with resistant species, hypha deformity in near immune species or hybrids was more serious, and the cell wall of hypha were thicker, hypha became darker, the vacuole was larger, some of the organelles disintegrated, and hypha cells were dead or near dead.(2) The restrain and death of haustorium in all incompatible combination were similar. All the haustoria showed deformity and darken, with irregular form and with more black grains on the plasmallemma. (3) The reaction of host cells to pathogen was different in different compatible combinations. When rust hypha grew in the intercellular spalls between cells or along the cell wall, the cells of mesophyll maintained in normal state within the susceptible species. In the resistant combination, the cell wall became thicker when contacted with hypha, and papilla formed to restrain the infection. There were some black deposit between cell wall and membrane. Nucleus, mitochondria, and golgiosome gathered around the haustorium. Chloroplast deformed, starch grain became smaller and disappeared. The tonoplast membrane broke and some dark grains deposited on it, and all other organelles disintegrated, granulated or vacuolized, and then died. Cells adjacent to the infected cells were normal in medium resistant species, cell disintegration and death were common in resistant and immune species, and cells adjacent to the infected cells disintegrated or died to different level. (4) The death of haustorium was earlier than the death of host cell. When haustorium deforming or in necrosis, organelles in the host cell were still normal. With the developing of infection, the necrosis occurred to haustorium and host cells. The host hypersensitive necrotic reaction was similar to other rust fungi.