【作者】 孙炳达；

【导师】 张天宇；

【作者基本信息】 山东农业大学 ， 植物病理学， 2003， 硕士

【摘要】 从全国17省市实地采集的3000多份植物标本进行保湿培养或组织分离法分离中，得到属于两属真菌的菌株200份，经鉴定，得到一个新种一燕麦生内脐蠕孢Drechslera avenicola B.D.Sun Sun et T．Y Zhang，5个中国新记录种：安德森内脐蠕孢D.andersenii Lam、黑麦草内脐蠕孢D.phlei(Graham)Shoem．、席氏内脐蠕孢D.sivanesanii C.Manoharachary et V.RT．Reddy、穆子突脐蠕孢E frumenracef(Mitra)Leonard & Suggs、小柄突脐蠕孢E.pedicellatium(Henry)Leonard & Suggs，国内已记录种11个：燕麦内脐蠕孢D.avenacea(M．A．Curtis ex Cooke)Shoem．、网斑内脐蠕孢D.dictyoides(Drechsler) Shoem、禾内脐蠕孢D.graminea(Rabenh．exSchlecht)Shoem．、大麦网斑内脐蠕孢D.teres(Sacc．)Shoem．、梭形突脐蠕孢E.fusiforme Alcom、环形突脐蠕孢E.holmii(Luttr．)I．enoard&suggs、长孢突脐蠕孢E.10ngisporium G．Y．Sun，R．Zhang，M．Q．Zhu&T．’~．Zhang、尖角突脐蠕孢E.monoceras(Drechslerl)Leonard & Suggs、 芦苇突脐蠕孢E. phragmatis W．P Wu、嘴突突脐蠕孢E.rostratum(Drechler)Leonard&suggs、大斑病突脐蠕孢E turcicum(PaSS)Leonard & Suggs。 对种内分生孢子形态变化较大的嘴突突脐蠕孢Erostratum的26个菌株作了RAPD分析，结果表明，该种种内遗传变异较大，但聚类结果的分组并不同于形态上的分组，且具有与形态学相似的无序性，分生孢子形态上的变化不能成为菌株间亲缘关系的标准，应该将该种作为一个群体对待，分生孢子形态在自然寄主上有些可能较规则，但从整个类群整体来看，在复杂多变地自然生态条件下，分生孢子形态变异的幅度大，应该以适宜产孢的一致培养条件下的特征作为分种的主要依据。 本研究的主要成果为，在前人工作基础上，通过系统深入的研究，订正了两属及其种的拉、汉名称，发现了一个新种，数个新记录种，增加了一些种的寄主及地理分布及存在状态，使我们能更全面地了解两属真菌在中国的分布。在研究过程中，始终注意分类方法及种级分类标准的探索、验证。对培养特征、内脐蠕孢属的产孢条件、分生孢子隔膜发育、萌发等特性进行了观察，总结出相对稳定、易行的属间及属内种间分类标准如下：1．属级分类标准(1)脐部特征是属的主要划分依据，Drechs．1era属真菌的脐点为腔孔型(atrium)，在观察中可以看到脐点决不突出分生孢子基细胞的光滑外形，有时甚至可以从侧面看到褐色的脐点凹陷在基细胞内，与孢子基部细胞壁之间分离，一般较大。 Exseroh，]um属真菌的脐点明显突出，电子显微镜下可见有一特殊的封套结构(enveloping structure)，此结构在光学显微镜下多数不能观察到，但在E.monoceras的有些分生孢子可以看到脐点顶端稍有环状加厚。<WP=9>(2)基部细胞的萌发特征可以很容易的区分Drechslez．a属真菌与Bipolaris属真菌，但后者与Exserohilum属真菌在分生孢子萌发特性之间却没有明显区别。(3)分生孢子颜色对分属有参考意义。(4)分生孢子梗的形态及产孢方式在区分Drechslera、Bipolaris和Exserohilume时，光学显微镜下可以区分的特征较少，在实际分类工作中价值较小。(5)分生孢子隔膜是假隔膜还是与外壁相连的真隔膜，在区分Exserohilum与脐点突出的弯孢属Curvularia的种类时，以前是很重要的标准，但此标准近来受到怀疑。2．种级分类标准(1)分生孢子形态大小、隔膜数量、细胞形状大小、次生分生孢子的情况在分种时有重要意义。一些参数，例如：平均细胞长度、顶部隔膜宽度与基部隔宽度比等，在个别形态特别相近的种相互区分时有特殊的价值。(2)分生孢子梗难以单独作为种间区分标准，其长度的变幅常相互交错，只能作为分种的次要标准。(3)寄主和培养性状在．Drechslera属的种间区分中较为重要，而在Exserohilum属内种间无明显的差异。 在我国丰富的自然生态条件下，深入研究肯定还会有该类群真菌的不断发现。而且，对于嘴突突脐蠕孢种内分生孢子形态的变异的深层原因、内脐蠕孢属的部分菌株的产孢条件都有待于继续研究。更多还原

【Abstract】 This study is about the taxonomic research of Drechslera Ito andExsehilum Leonard & Suggs in China. About 200 isolates were receivedfrom more than 3000 herbarium specimens, which we have collected frommany provinces of China. From the isolates, we have found one new species, D. a venicola B. D.Sun et T. Y. Zhang, five Chinese new record species, D. andersenii Lam,D. sivanesanii C. Manoharachary et V. R. T. Reddy, E. frumentaeei (Mitra)Leonard & Suggs, E. pedicellatium (Henry) Leonard &Suggs and elevenspecies which had been reported in China, they are , D. avenacea(M.A.Curtis ex Cooke) Shoem., O. dictyoides (Drechsler) Shoem.,D. graminea (Rabenh. ex Schlecht.) Shoem., D. phlei (Graham) Shoem.,.D. teres (Sate.) Shoem., E. fusiforme Alcom, E. holmii (Luttr.) Lenoard& suggs, E. ]ongisporium G.Y.Sun, R.Zhang, M.Q.Zhu & T.Y.Zhang,E. monoceras(Drechsler) Leonard & Suggs, E. phragmatis W.P Wu,E. rostratum (Drechler) Leonard & Suggs and E. turcicum (Pass.) Leonard& Suggs. To investigate the genetic variation in E.rostratum, a total of 26E.rostratum isolates and 7 isolates of other species were analyzed with 10random amplified polymorphic DNA (RAPD) primers. The results showedthat there was a similar disorderliness with conidia morphology showed. Therewas a large variation among all E.rostratum isolates, and character of conidiawas not a critical criteria of relationship between isolates. We should treat allisolates of E.rostratum as one group since there were no constant crt. The conidia from culture medium shows less variety whentreated all isolates of E.rostratum as a whole, and should be treated as maincriteria of classification of this species. After many works have been done about this two genera, the main resultsof this research are the revisions of the Latin and Chinese name of the genera<WP=11>and the species in them. We also have found a new species, several newChinese record species and broadened the hosts’ records and distribution ofsome species. All the works will contribute to the further study of this group offungi. In our research work, we ve payed a constant attention to the taxonomicmethods and the testifying and exploring of criteria to differentiate species. Westudied the culture character of all isolates, the conditions to spur Drechsleraspp to produce conidia on culture medium, the formation of conidia septum,the germ character of conidia etc, and have concluded a much easier andfeasible criteria for the classification this group of fungi. In differentiating different genera, the character of hilum plays animportant role. The hilum of Drechslera spp is atrium type hilum, which islarger and we can see them never protruding from the contour of basal cellwhen under optical microscope. Some time we can even see them were in thebasal cell of conidia, and clear of the cell wall. The hilum of Exserohilum spp.were protruding and had an enveloping structure. But this structure can not befound using optical microscope. Only that you may found an ring thickness atthe top of the hilum of E.monoceras and several other species. Thegermination character of the basal cell of conidia is useful in distinguishingDrechslera spp. from Bipolaris spp and Exserohilum spp But this character haslittle difference between the later two genera. The color of conidia only has anassitant role in genus classification. The Exserohilum spp have distoseptatesand the Curivularia spp with protruding hilum have euseptates has been seenas the main difference between them. This criteria is used even it has beendoubted because there is no other criteria better. In treating with the species, the morphology of conidia is main criteria,especialy the shape and the size of conidia, the shape of conidia cell, theconidia septum and the existence of secondary conidiophore and secondaryconidia. Some parameter such as the ratio of width of a更多还原