【作者】 蔡邦平；

【导师】 陈俊愉； 郭良栋；

【作者基本信息】 北京林业大学 ， 园林植物与观赏园艺， 2009， 博士

【摘要】 梅是中国特产的著名果树和花木,是我国自然状况下最早开花的木本花卉,栽培与应用历史悠久,野生分布于我国南方十五省（区）,引种栽培几乎遍及中国大部分地区。本项目研究梅形成共生菌根的丛枝菌根真菌（AMF）多样性,通过采集主要野生分布区和栽培区的梅根系和根际土壤,应用染色镜检法测定根系的侵染、形态学方法鉴定丛枝菌根真菌种类、分子生物学方法检测丛枝菌根真菌居群多样性,研究结果探清梅共生菌根的类型、AMF菌根真菌种类、生态分布等规律和特点,取得一系列的创新性研究成果,对于梅的栽培、花果品质改良、生理与生态学研究都有着重要的理论与实践意义。主要研究结果如下:1、本研究首次确定梅的丛枝类型为疆南星型（Arum-type）,无隔胞间菌丝直径2～12μm,泡囊形状多种、以椭圆形为多、直径10～120μm,侵入菌丝有单菌丝、多菌丝、匍匐菌丝等形式。以直径小于0.5mm的细根测定侵染率,其值为8.39～32.22%,不同地域取样的根系AM侵染率呈极显著差异;在不同季节中,春季的梅根系AM侵染率、侵入点、泡囊和丛枝均高于其它季节的。2、根据孢子形态特征鉴定,从梅根际土壤中分离得到AMF种类99个种,分属于11属,属数占世界属总数的81.8%;鉴定种类89个,种数占全世界已知种总数的43.0%;其它还有10个为未描述种。其中拟定新种2个（梅花球囊霉Glomus mume和刺环孢囊霉Kuklospora spinosa）、中国新记录种20个,而且环孢囊霉属Kuklospora、类球囊霉属Paraglomus和内生球囊霉属Intraspora为中国首次报道的三个属,极大地丰富了中国AMF种质资源,这是我国报道AMF资源种类最多的一次。3、从11个采样地点分离得到AMF 99种,其中G.claroideum和G.geosporum在所有采样地点均有分布,属于广分布种;G.mosseae和G.rubiforme 2个种在10个采样地点中有分布,分布较广;有39个AMF种仅在1个采样地点中分离得到,占总种数量的39.4%,分布在1-2个采样地的AMF种类累计为63种,占总数的63.6%,这些种均是分布区域较狭窄的种类。4、野梅根际土壤中AMF种类为32-38种/样地,而栽培梅园分离得到的AMF种类为19-25种/样地。梅自然分布中心--藏、川、滇的根际土壤中AMF多样性指数分别为2.68、2.62、2.53,是研究区域中最高的三位。根据AMF多样性指数、孢子密度、种丰度、种数、属数进行聚类分析,可划分为四类。5、在所调查的范围内,梅根际土壤的AMF多样性指数（H）随海拔上升而增多、随经度升高而降低;孢子密度（SD）也是随着海拔上升而增多、野生梅土壤的孢子密度明显高于栽培梅的;种丰度（SR）在黄壤、棕壤、红壤、黑壤中递增,随着有机质、全氮、有机氮的增多而升高。通径分析表明,对梅根际土壤AMF孢子密度、种丰度和多样性指数起直接效应的只有经度（x₁）、纬度（x₂）、海拔（x₃）、pH（x₄）、全磷（x₅）、有机磷（x₆）、有机氮（x₇）等7个因素,根据这7个因素的效应,可建立多元线性回归方程:H=50.085-0.025 x₁+0.006 x₂+0.0000515 x₃-0.031 x₄+0.18 x₅+0.0000562 x₆SD=5710.333+0.342x₁-70.884x₂+0.088x₃-170.629x₄-1080.973x₅-0.602x₆-0-158x₇SR=-300.776+00.299x₁-0.131 x₂+0.002 x₃+0.754 x₄+00.934 x₅-0.01 x₆+0.011 x₇6、在极端生态条件下,梅根际土壤的AMF群落表示出一定的特异性。贵州喀斯特地区的AMF种类以具孢子果的小孢子种类相对较多、西藏林芝地区以无梗囊霉属的种类居多。7、北京地区在四个季节中,梅根际土壤的AMF种类:春季17种,夏季16种,冬季12种,秋季为10种、最少;多样性指数:秋季>夏季>春季>冬季;各个季节的根际土壤AMF种的差异较大,春季与夏季的种相似性系数最大为0.42,而冬季和秋季的种相似性系数最低仅为0.27。从武汉梅园的春、秋季AMF群落组成变化和藏东南地区野梅的花、果期AMF群落组成变化来看,春季（花期）的AMF多样性指数高于夏季（果期）或秋季。8、以武汉春季采取的梅根际土壤和根系样品,通过nested PCR的AFLP分子标记分析,得知土壤的AMF基因组DNA多态性位点为6.5个,明显多于根系内的3个位点。其中土壤的AMF基因组DNA多态性位点数与孢子形态鉴定的种类数量基本吻合。根据AFLP标记结果聚类,梅品种根系内AMF基因组DNA的聚类类别与梅品种的“品种群”这一分类级别无相关关系。更多还原

【Abstract】 Prunus mume Sieb.et Zucc.is a famous ornamental and fruit tree,distributed in fifteen provinces of southern areas,and cultivated in almost all parts of China.The anthesis of P.mume is the earliest among all floras in nature,and the history of its application and cultivation is for a long time in China.The study of diversity of arbuscular mycorrhizal fungi（AMF） associated with P.mume in China was carried out,in order to explore AM colonization,species and ecological distribution of AMF.Rhizosphere soil and root samples were collected from both the main distributions and P.mume gardens in China.Spores of AM fungi were isolated from 100 g air-dried soil for each soil sample using the wet-sieving and decanting method,observation of AM structure using the root staining method,and molecular diversity of AMF was analysed based on AFLP marker.The main results are as follows:1.AM structures,i.e.vesicles,entry points,Arum-type arbuscules,hyphal coils,and non-septate hyphae,were present and measured in all samples.The indexes of AM colonization in fine root were significantly higher than that of moderate and thick root,in a range of 8.39～32.22%.The colonization rates were various among different sites,and also various for the colonization among four seasons, being highest in spring sample root.2.A total of 99 morphospecies belonging to 11 genera were isolated from all sample soils.Among them,there were 89 species identified,occupying 43%of the described AMF species in the world,two new species,i.e.Glornus mume and Kuklospora spinosa,were found and 20 new Chinese records were reported.3.AMF species G.claroideurn and G.geosporum were isolated from all 11 sampling sites,and G. rnosseae and G.rubiforme were found from 10 sampling sites.On the other hand,39 species（39.4%） were only isolated from one sampling site,and 24 species（24.2%） were found from two sampling sites. So that,there were wide or limited distributing species for AM fungi associated with P.mume.4.There were 32-38 AMF species / sample site in wild P.mume distribution,only 19-25 species / sample site in Mei cultivar garden.The Shannon-Weiner diversity index（H） of AMF isolated from Tibet, Szechwan and Yunnan,in the wild P.mume distribution core,was 2.68,2.62 and 2.53,which were the three highest values in the 11 sample sites.They could divided into four groups according to the hierarchical cluster analysis based on AMF Shannon-Weiner diversity index（H）,spore density（SD）, species richness（SR）,species and genus number.5.It was positive correlation between AMF Shannon-Weiner diversity index（H） and sample altitude, spore density（SD） and altitude,species richness（SR） and organic matter or organic N,but it was negative correlation between H and sample longitude.Only seven factors,i.e.sample longitude（x₁）, latitude（x₂）,altitude（x₃）,pH（x₄）,total P（x₅）,organic P（x₆）,organic N（x₇） were direct effected the H, SD and SR of AMF based on path analysis.The optimization curve estimation regression model was made as follow:H=50.085-0.025 x₁+0.006 x₂+0.0000515 x₃-0.031 x₄+0.18 x₅+0.0000562 x₆SD=5710.333+0.342x₁-70.884x₂+0.088x₃-170.629x₄-1080.973x₅-0.602 x₆-0.158x₇SR=-300.776+00.299 x₁-0.131 x₂+0.002 x₃+0.754 x₄+00.934 x₅-0.01 x₆+0.011 x₇6.There were some specialties for the AMF community in an extremity environment.AMF most frequently isolated were small（Mean spore diameter≤100μm） and sporocarpic species in karst area in Guizhou,but species of Acaulospora were most frequently found and Acaulospora was one of the dominant genus in southeast Tibet.7.The seasonal dynamics of arbuscular mycorrhizal（AM） fungi associated with P.mume cultivated in Beijing was carded out.There were 17 species in spring,16 species in summer,12 species in winter, and only 10 species in autumn,and Sorenson similarity coefficient was less than 0.42 among seasons in the taxonal level.The result of the changing AMF community between spring and autumn in Wuhan Mei Garden,spring and summer in southeast Tibet also showed that the Shannon-Weiner diversity index （H） was higher in spring.8.Molecular diversity of AMF was analyzed,by DNA amplification by nested PCR based on AFLP marker.The results showed that there were average values of 6.5 polymorphic loci in the AMF DNA from sample soils,more than 3 polymorphic loci from roots.The number of polymorphic loci from soil AMF DNA was similar with the number of AMF species isolated from soil.The clustered groups of AMF DNA by AFLP marker from the roots of different cultivars of P.mume were not equal to cultivar groups.更多还原