苹果属不同种对褐斑病菌生长发育的影响

利用荧光显微镜技术观察苹果褐斑病菌(Diplocarpon mali)接种苹果品种富士和砧木山定子叶片后不同时间点的生长发育特点。接种富士6h后分生孢子即可萌发入侵,24h在表皮细胞中形成吸器,3d在叶组织中形成菌落并已扩展至海绵组织,5d后观察到特殊的角质层下菌丝束(SHS)组织,7d即可观察到大量分生孢子盘。虽然病菌在山定子叶片中的生长发育过程与在富士上相似,但发育明显延迟,接种后3d在角质层下扩展并侵染表皮细胞形成吸器;7d时仍局限在侵染点周围,未观察到SHS组织;11d始见个别分生孢子盘。且接种后12h在侵染点周围的表皮细胞壁上有明显的胼胝质沉积,说明山定子对褐斑病的抗性明显大于富士,可用于进一步的抗病机理研究和应用。

Effect of Different Malus Species on Growth and Development of Diplocarpon mali

Isolate 289 of Diplocarpon mali,was inoculated on Malus domestica Borkh.cv.Fuji and Malus baccata(L.) Borkh.The growth and development of D.mali was investigated with fluorescence microscopy.The results showed that the conidia germinated 6 h post-inoculation on M.domestica cv.Fuji,and produced typical haustoria 24 h post-inoculation.Three days post-inoculation,colonies were formed in the leaf tissue and the pathogen had been extended to spongy tissue.Five days post-inoculation,the subcuticular hyphal strands(SHS) were observed.And acervuli appeared on inoculated leaves 7 days post-inoculation.Although the infection process on M.baccata was the same as that on M.domestica cv.Fuji,the growth and development of the pathogen were much slower.The pathogen was mainly expanded under the cuticle,and produce haustoria in epidermal cells to uptake nutrients 3 days post-inoculation.Even in 7 days post-inoculation,the extension of the pathogen was limited in the area around the infection sites,no SHS was observed.About 11 days post-inoculation,limited acervuli were observed on M.baccata.Additionally,callose was observed on the epidermal cell wall around the infection sites 12 h post-inoculation.These results indicated that M.baccata was more resistant to D.mali compared to M.domestica cv.Fuji.It could be used to study the resistant mechanisms of the host and to develop novel resistant cultivars.