论文部分内容阅读
蔓割病是我国南方薯区甘薯主要病害之一,本研究采用直接观察、显微和超微结构观测等方法,对高抗、中感和高感蔓割病的3个甘薯品种(高抗品种:金山57,中感品种:热薯1号,高感品种:新种花)接种蔓割病菌28 d植株充分发病后其茎基部细胞的侵染结构进行了观察。结果表明,在用清水作对照处理时,3个品种茎部组织的细胞形态和结构正常且完整,细胞代谢强。高抗品种金山57无论是接种组还是对照组,均未发现病原菌丝的存在,其茎下部、中部和上部细胞结构相对完整。中感品种热薯1号,蔓割病菌从其茎基部侵入后导致茎基部细胞破损坏死,而中部寄主-病原互作较为活跃和典型,造成养分运输受阻,茎基部接种后病原菌丝会沿着寄主茎部的维管束和其他组织一直向寄主的茎部末端蔓延,遭受侵染后的部位其细胞反应与高感品种新种花类似。高感品种新种花遭受蔓割病原菌侵染后,病原菌菌丝从茎基部新鲜剪口侵入后进入表皮细胞、皮层、维管束并在甘薯茎基部蔓延至中部、上部,直至寄主整株枯死,甘薯茎的木质部导管出现侵填体,质壁分离;与此同时,细胞壁的沉积物及乳突在病原菌的入侵处形成,各种无定型物质或纤丝构成的织网迅速包围入侵菌丝。
One of the main diseases of sweet potato in southern potato area of China is the vine-cutting disease. In this study, three sweet potato cultivars with high resistance, medium and high susceptibility (high resistance Varieties: Jinshan 57, susceptible varieties: Hot potato 1, high susceptible varieties: new species of flowers) inoculated with pathogenic bacteria 28 d after the full incidence of infection of the stem cell structure were observed. The results showed that the cell morphology and structure of the stems of the three cultivars were normal and intact and the cell metabolism was strong when treated with fresh water. Jinshan 57, a high-resistant variety, showed no pathogenic mycelium in both inoculation and control groups, and its stem, middle and upper cells were relatively intact. In the susceptible strain, Hot Potato No.1, the bacteria invaded from its stem base, resulting in cell damage and necrosis of the stem base, while the host-pathogen interaction in the middle was more active and typical, resulting in the obstruction of nutrient transport. Vascular bundles and other tissues of the host stem have been propagated to the host’s stem end, and their cellular responses at the site of infection are similar to those of the highly susceptible species. After the new species of high-susceptible species invaded by the pathogen, the pathogen mycelium invaded into the epidermal cells, cortex and vascular bundles from the base of the fresh stalk and spread to the middle and upper part of the base of the sweet potato until the whole host died, In the same time, the cell wall deposits and papillae formed at the invasion of pathogenic bacteria, and various kinds of webs composed of amorphous materials or fibrils rapidly surrounded invading hyphae.