龙南钾矿区常见蕨类植物可培养内生真菌的多样性

Diversity of culturable endophytic fungi separated from seven common ferns in potassium mine areas in Longnan, South Jiangxi Province

关键词:  钾矿区, 蕨类植物内生真菌, 优势菌群, 多样性指数, 相似性系数

Key words:  potassium mine areas, endophytic fungi in ferns, dominant endophytic fungi, diversity index, similarity coefficient

摘要:

植物内生真菌作为一类特殊的微生物资源,与宿主在长期的生态系统演化过程中形成了互惠共生关系,通过多样化途径来增强植物体的营养生理和抗性机能,对宿主植物产生多种有益生物学作用,在植物演替过程中具有重要的生态学意义。这种特殊微生物资源近年来倍受关注,而利用植物-真菌共生体强化植物在矿区逆境中生长,提高矿区生物修复效率是一个新的研究热点。为探明钾矿区不同蕨类植物内生真菌的物种多样性、群落组成以及生态分布规律,该研究以芒萁、狗脊、禾秆蹄盖蕨、海金沙、华中铁角蕨、井栏边草和乌蕨等植物为材料,采用组织分离、形态学鉴定等方法,对其内生真菌多样性进行分析。结果表明:从7种植物中共分离获得377株内生真菌,总分离率在2.50%～4.52%之间。经鉴定377个菌株隶属于链格孢属、曲霉属、枝孢菌属和轮枝孢属等25个分类单元,其中链格孢属、曲霉属、枝孢菌属和轮枝孢属等在所有被调查蕨类植物中都有分布,为优势属,共计为185株,占总株数的49.07%,但它们在每种植物的分布存在明显差异; 7种蕨类植物内生真菌总定植率为叶高于根状茎(P<0.05),多样性指数在0.502～0.867之间,但每种植物及其不同组织部位的内生真菌定植率和多样性指数存在一定的差异; 从相似性分析来看,同一个钾矿区不同蕨类植物内生真菌菌群之间的相似性程度较低,相似性系数在0.189～0.587之间。该研究结果不仅丰富了植物内生真菌种质资源,而且为进一步开展植物内生真菌强化宿主植物在钾矿区生长适应机制的研究奠定了基础。

Abstract:

Plant endophytic fungi is a special kind of microorganisms mutualistic ally symbiosed with host plants. The special microbial resources have attracted tremendous interests in recent years, because of their potential to address problems associated with enhanced plant growth in environmental stress of mines and to improve the efficiency of ecological restoration. With a long peoriod of evolution, endophytic fungi and their host plants have formed a closemutual symbiotic relationship. Many beneficial biological effects have been made on the host plants, and they have the important ecological significance in plant community succession process. It is widely attracted using plants-microorganisms to enhance plant growth in environmental stress of mines, and to improve biological restoration efficiency, and its significance to host plants has become a new hot issue. In order to make clear the species diversity, community composition and ecological distribution of endophytic fungi, we carried out our work among 7 species of common ferns in potassium mine areas in Longnan, South Jiangxi Province. They are Dicranopteris linearis, Woodwardia japonica, Athyrium yokoscense, Stenoloma chusanum, Lygodium japonicum, Asplenium sarelii and Pteris multifida. And we analyzed the diversity of endophytic fungi, using the method of tissue isolation, morphological identification. The results showed that 377 strains of endophytic fungi were isolated from 7 species of plants, and the separation rate ranged from 2.50% to 4.52%. All of 377 strains belong to 25 genera, and among them, Alternaria, Aspergillus, Cladosporium and Verticillium,which are found in all these 7 fern species, indicated that they were dominant, but there were obvious differences in the distribution in each fern species. The total separation rate and the colonization rate of entophytic fungi from leaves are generally greater than that from the rhizomes, but there are some differences in the total separation rate and the colonization rate from different parts of each fern species. The diversity indexes of endophytic fungi range from 0.502 to 0.867 in the seven species of ferns. It indicated that there was high diversity of endophytic fungi in potassium mines and the low similarity of endophytic fungi in different ferns in the same mine areas. The similarity coefficients of the endophytic fungi in the seven species of ferns were from 0.189 to 0.587. The results of this study would not only enrich germplasm resources of plant endophytic fungi, but also would offer basic data for further research on the mechanism that endophytic fungi could strengthen the adaptation of the host plant on mineral nutrition and stress physiology in potassium mine areas.