【作者】 徐严；

【导师】 龚国淑；

【作者基本信息】 四川农业大学 ， 植物病理学， 2008， 硕士

【摘要】 本文采用全球定位系统（GPS）采集了若尔盖高原湿地74个样点86个土样,用稀释平板法对该区土壤真菌进行了分离计数。对分离到的真菌进行了初步鉴定,并分析了真菌数量与土壤类型、土壤质地、土壤养分、土壤水分、pH等土壤环境因子的相关性;同时在ArcGIS9.0平台上运用地统计学方法研究了该地区土壤真菌数量的空间分布特征。根据土壤真菌的数量、种群及其分布研究该地区土壤真菌的物种多样性。还分析了若尔盖高原湿地土壤木霉的种类及土壤木霉在拮抗病原菌和分解纤维素方面的潜在能力。主要研究结果如下:若尔盖湿地土壤真菌数量为9.68×10²±2.48×10^-3（10.8～1.41×10⁴）cfu.g^-1干土。不同样点的土壤真菌总数存在较大差异,真菌数量最高达1.41×10⁴ cfu.g^-1干土,最低仅有10.8 cfu.g^-1干土,相差100倍以上。同一样点内,土壤真菌数量随土层深度增加而减小。不同地理区域,土壤真菌的数量分布表现为嫩哇(1865.263 cfu.g^-1)＞唐克(1543.246 cfu.g^-1)＞班佑(823.010 cfu.g^-1)＞辖曼(285.098 cfu.g^-1)＞阿西(134.751cfu.g^-1)。不同土壤类型方式下,土壤真菌数量表现为沼泽土(3.80×10³ cfu.g^-1)＞泥炭土(2.72×10³ cfu.g^-1)＞草甸土(1.08×10³ cfu.g^-1)＞风沙土(0.27×10³ cfu.g^-1)。真菌数量随土壤质地的不同而表现为中壤土(1.74×10³ cfu.g^-1干土)＞轻壤土(1.38×10³cfu.g^-1干土)＞砂壤土(0.34×10³ cfu.g^-1干土)＞砂土(0.17×10³ cfu.g^-1干土)。若尔盖高原湿地土壤真菌数量的空间分布呈呈环状或条块状分布,整体上由湿地外围向内部逐渐增加。74个表层土经分离共获得771株土壤真菌。分布范围较广的真菌为青霉（Penicillium spp.）、木霉（Trichoderma spp.）、镰刀菌属（Fusarium spp.）、腐霉属（Pythium spp.）、酵母类真菌、曲霉（Aspergillus spp.）和毛霉（Mucor spp.）,其分离频率分别为98.68%、63.51%、31.08%、21.63%、33.78%、25.68%和29.73%,在真菌总数中所占的比例分别为21.79%、12.71%、4.41%、3.89%、4.67%、3.50%和3.63%。土壤真菌与土壤生态因子间的相关分析表明,真菌数量与土壤中全钾、有机质含量以及土壤含水量均呈正相关,与pH值土壤全氮、全磷、速效钾、速效磷、碱解氮呈负相关。其中真菌数量与速效钾和碱解氮含量呈显著负相关。另外,真菌数量与物种丰富度（S）、Shannon-wiener指数（H′）呈负相关,相关系数较小。土壤真菌的物种丰富度（S）、Shannon-wiener指数（H′）、Pielou均匀度指数（E）和优势度指数（D）分别为6.8649±3.0805、0.7650±0.2498、0.9697±0.0627、0.2418±0.1353。辖曼地区土壤真菌物种丰富度（S）和Shannon-wiener指数（H′）最高,分别达8.400和0.8759。从若尔盖高原湿地土壤中分离木霉菌株98个,其中哈茨木霉19株,黄绿木霉29株,深绿木霉10株,康氏木霉12株,绿色木霉13株,长枝木霉7株,还有木霉组的棘孢木霉6株,粗梗组的淡黄木霉2株。木霉生长速度测定结果表明,多数木霉菌株生长速度迅速,为空间和营养资源的强竞争者。对峙培养中,木霉菌株对立枯丝核菌均有一定程度的抑制作用,其中T1、T2和T5的抑制率较高在75%以上。难挥发性代谢产物的抑制效果显著,T23、T27、T25、T28和T32效果最好。通过纤维素分解实验,从分离出的98株木霉中初步筛选出具有纤维素分解能力的菌株29株。再经过刚果红纤维素培养基的筛选,有7株木霉分解纤维素能力较好,其中5株为绿色木霉,另外2株为黄绿木霉和康氏木霉。更多还原

【Abstract】 86 soil samples of 74 plots,located by GPS（Global Position System）,were collected from the Zoige plateau wetland.Quantities of fungi were determined with the dilution plate technique.The soil fungi were identified and the correlations between fungi quantities and soil ecological factors which included soil fertility,soil humidity,land-use type and pH were analyzed by using the software of SPSS.According to the quantities,communities and their distribution,the fungi diversity was also studied.Potential which could antagonize to pathogen and decompose cellulose was also analyzed.Fungi quantity ranged from 10.8 to 1.41×10⁴(cfu·g^-1 dry soil).At the same plot,there were more fungi in upper（0～20cm） than in deeper soil layers（20～40cm）.In different regions,fungi quantities from high to low were as follows:Nengwa(1865.263 cfu.g^-1 dry soil)＞Tangke(1543.246 cfu.g^-1 dry soil)＞Banyou(823.010 cfu.g^-1 dry soil)＞Xiaman (285.098 cfu.g^-1 dry soil)＞A’xi(134.751 cfu.g^-1 dry soil).In different land patterns,swamp land(3.80×10³ cfu·g^-1 dry soil)＞turf land(2.72×10³ cfu·g^-1 dry soil dry soil)＞meadow land (1.08×10³ cfu·g^-1 dry soil)＞sand land(0.27×10³ cfu·g^-1 dry soil).The spatial distribution of soil fungi mainly exhibited as strip zonal and circularity patterns.And the content of soil fungi increased gradually from outside toward center.The regions with low content(＜250 cfu·g^-1 dry soil) were mainly distributed in the north of A’xi and Heihe.The regions with high content(＞2500 cfu·g^-1 dry soil) were mainly located in the northeast of Nengwa and Tangke and Qi-Daoban of Banyou.A total of 771 fungi isolates were collected from the soil in the Zoige plateau wetland. 25 fungal genera were identified.Among these genera,Penicillium spp.,Trichoderma spp., Fusarium spp.,Pythium spp.,yeast,Aspergillus spp.and Mucor spp.were isolated more frequently at 98.68%,63.51%,31.08%,21.63%,33.78%,25.68%and 29.73%in these samples,respectively.Their proportions of quantity were 21.79%,12.71%,4.41%,3.89%, 4.67%,3.50%and 3.63%,respectively.Soil fungi quantities were closely correlated with soil ecological factors.At some degree,fungi quantity was correlated with total potassium,organic matter and water contents positively,but with pH,total phosphorus,rapidly available potassium,rapidly available nitrogen,rapidly available phosphorus,slowly available potassium and total nitrogen negatively.The fungi quantity had a significantly negative correlation with soil available potassium and rapidly available nitrogen.In addition,the relationship was noticed between soil fungi quantities and community diversity.The quantity of fungi had a low negative correlation with the abundance（S） and Shannon-wiener’s diversity（H′）.The abundance（S）,Shannon-wiener’s diversity（H′）,Pielou’s evenness（E） and dominance index（D） were 6.8649±3.0805,0.7650±0.2498,0.9697±0.0627 and 0.2418±0.1353, respectively.Fungi quantity in Nengwa was the most,but in Xiaman the abundance（S） and Shannon-wiener’s diversity（H′） were the most.They were 8.400 and 0.8759,respectively.98 Trichoderma isolates were isolated from the Zoige plateau wetland.There were 19 isolates of T.harzianum,29 isolates of T.aureoviride,10 isolates of T.atrooviride,12 isolates of T.koningii,13 isolates of T.viride,7 isolates of T.longibrachiatum,6 isolates of T.asperellum,2 isolates of T.cerinum,respectively.The test of hyphal growth rate showed that most of Trichoderma strains grew rapidly, and were the stronger competitor for space and nutrition resource.The result of the dual culture showed the inhibition rates of hypaal growth of Trichoderma against Rhizoctonia solani were 33.43%～77.99%,T1,T2 and T5 showed higher inhibition rates than 75.00%. The non-volatile substances of the isolates tested had obvious inhibition to hyphal growth of R.solani,among them T23,T27,T25,T28 and T32 showed higher inhibition rates.From the primary screen by Hechisum medium,there were 29 Trichoderma strains having the ability of decomposing cellulose,which were screened from all 98 Trichoderma. There were 7 Trichoderma having higher ability of decomposting cellulose from the re-election holding on cellulose-congo red medium.更多还原