霉菌的形态特征.ppt

实验九 霉菌的形态观察与鉴定(霉菌的无性孢子和有性孢子的形态观察)一、教学要求学习并掌握观察霉菌形态的基本方法。二、实验原理l霉菌的形态 Molds are multinucleated,filamentous fungi composed of hyphae.A hypha is a branching,tubular structure from 2-10 m in diameter and is usually divided into cell-like units by crosswalls called septa.The total mass of hyphae is termed a mycelium.The portion of the mycelium that anchors the mold and absorbs nutrients is called the vegetative mycelium;the portion that produces asexual reproductive spores is termed the aerial myceliumMolds reproduce primarily by means of asexual reproductive spores such as conidiospores,sporangiospores,and arthrospores.These spores are disseminated by air,water,animals or objects and upon landing on a suitable environment,germinate and produce new hyphae.Molds may also reproduce by means of sexual spores such as ascospores and zygospores,but this is not common.The form and manner in which the spores are produced,along with the appearance of the hyphae and mycelium,provide the main criteria for identifying and classifying molds.Bread Mold Spores on Fungal Fruiting Structure,Rhizopus sp.(SEM x2,990)Fungal Mycelium with Spores,Penicillium sp.(SEM x3,220)Black Mold,Aspergillus variecolor.(SEM x2,315)观察方法直接制片观察，载玻片培养观察，玻璃纸培养观察 三材料与器材菌种：曲霉(Aspergillus sp.),青霉，根霉(Rhizopus sp.)和(Mucor sp.)培养2-5 d 的马铃薯琼脂平板培养物.试剂：乳酸石炭酸棉蓝染色液无菌吸管，平皿，载玻片，显微镜等四 操作程序l 直接制片观察l于洁净载玻片上，滴一滴乳酸石炭酸液于载片中央，用解剖针从霉菌菌落的边缘处取小量带有孢子的菌丝置于液滴中，再细心地将菌丝挑散开，然后小心地盖上盖玻片，注意不要产生气泡。置显微镜下先用低倍镜观察，必要时再换高倍镜。五 注意事项l挑菌和制片时要细心，尽可能保持霉菌自然生长状态。l加盖玻片时切勿压入气泡，以免影响观察。六 思考题l青霉和曲霉的形态有哪些异同？l要观察构巢曲霉的闭囊壳，制片时要注意哪些问题？