广西木论国家级自然保护区野生兜兰的生境调查

Habitat Investigation of Wild Paphiopedilum in Mulun National Nature Reserve of Guangxi

摘要: 为了深入了解桂西北岩溶地区野生兜兰的分布及保护状况，以广西木论国家级自然保护区小叶兜兰、硬叶兜兰、白花兜兰、麻栗坡兜兰和带叶兜兰等野生兜兰为研究对象，通过野外调查和实验研究，观测野生兜兰在木论保护区的种群数量及分布、植物群落结构组成，分析兜兰分布点的土壤微生物种群多样性，并对其土壤理化性质进行测定，以便为野生兜兰的生物学保育及引种栽培提供参考。结果表明：1) 麻栗坡兜兰和白花兜兰分布点的植物群落成层现象明显，可分为乔木、灌木和草本层三层，其中麻栗坡兜兰生境相对较好，土壤腐殖质丰富，小叶兜兰、白花兜兰、带叶兜兰分布的生境比较相近，生长在石壁或石缝中，生存环境恶劣，种子繁殖率低，对环境依存度较高，这是其种群濒危灭绝的原因之一；2) 五种野生兜兰根际土壤真菌在门水平上主要包括担子菌门和子囊菌门，在目水平和属水平上微生物种类比较丰富，细菌在门水平上主要包括放线菌门、变形菌门和酸杆菌门；兜兰主要分布点土壤微生物中的真菌和细菌种类比较丰富，不同生境的土壤微生物种群差异明显，说明在喀斯特岩溶地区，土壤微生物对野生兜兰种群分布具有重要的作用，也说明了野生兜兰对喀斯特岩溶地区生境要求的特异性；3) 木论保护区五种野生兜兰根际土壤的pH在6.49~8.39之间，N、P、K和有机质含量总体上属于中等偏上水平；无论是同一采集地的不同兜兰或不同采集地的同种兜兰，其根际土壤理化性质均有显著差异，也就是说，每个采集地的野生兜兰都有一定的生境要求，并能较好地适应不同的生境。

Abstract: In order to understand the distribution and protection status of wild Paphiopedilum in karst areas of northwest Guangxi, the wild Paphiopedilum, P. barbigerum, P. micranthum, P. emersonii, P. malipoense, P. hirsutissimum are taken as the research object. Through field investigation and experimental research, the population and distribution of wild Paphiopedilum in the Mulun nature reserve, as well as the composition of plant community structure are observed. In order to provide references for the biological conservation and introduction and cultivation of wild Paphiopedilum, the microbial population diversity and the physical and chemical properties of rhizosphere soil at Paphiopedilum distribution points are determined. The results showed that: 1) The plant communities at the distribution points of P. malipoense and P. emersonii have obvious stratification, which can be divided into three layers: trees, shrubs and herb layers. Among them, P. malipoense has a relatively good habitat, and the soil is rich in humus. The habitats of P. barbigerum, P. emersonii and P. hirsutissimum are similar. They grow in rock walls or cracks. They live in a harsh environment, have a low seed reproduction rate and a high degree of dependence on the environment. This is one of the reasons why its population is endangered; 2) Five species of wild Paphiopedilum rhizosphere soil fungi mainly include Basidiomycota and Ascomycota at the phylum level. Microorganisms are abundant at the order and genus level. Bacteria at the phylum level mainly include Actinomycetes, Proteobacteria and Acidobacteria; the main distribution points of Paphiopedilum are rich in fungi and bacteria in soil microbes, and soil microbial populations in different habitats are significantly different. This indicates that in karst areas, soil microbes have a strong influence on wild Paphiopedilum. It shows that in karst areas, soil microorganisms play an important role in the distribution of wild Paphiopedilum populations, and it also explains the specificity of wild Paphiopedilum to the habitat requirements of karst areas; 3) The pH of the rhizosphere soil of 5 wild Paphiopedilum species in Mulun nature reserve is between 6.49~8.39. The content of N, P, K and organic matter is generally above the middle level; whether it is different Paphiopedilum from the same collection site or the same species of Paphiopedilum from different collection sites, the physical and chemical properties of the rhizosphere soil are significantly different. That is to say, the wild Paphiopedilum of each collection site has certain habitat requirements, and can adapt to different habitats.