盐碱地引种沙枣根瘤内生菌及根际土壤AM真菌的多样性

Diversity of Root Nodule Endophytes from Elaeagnus angustifolia L. and Arbuscular Mycorrhizal Fungi from Rhizosphere in Saline-alkali Soil

为了揭示黑龙江省盐碱地引种沙枣根瘤内生菌及根际土壤丛枝菌根(Arbuscular Mycorrhizal,AM)真菌的多样性,采用根瘤切片法和湿筛法并结合分子生物学手段对沙枣根瘤内生菌及根际土壤中的AM真菌进行分离、鉴定和多样性分析。研究结果表明:从沙枣根瘤内成功地分离和鉴定出了27个纯菌株,其中放线菌4株、细菌14株、真菌9株,内生细菌的多样性指数最为丰富,与根瘤形成有关的内生放线菌多样性指数最低,但放线菌类群中Frankia sp.(代号H01)菌株优势度指数和均匀度指数最高;从沙枣根际土壤中共分离和鉴定出5属8株AM真菌,Glomus属有3株,Funneliformis属有2株,Septoglomus属有1株,Rhizophagus属有1株,Acaulospora属有1株。Rhizophagus intraradices在样品中的分离频度达到了100%,孢子密度高达48.5个/50 g土,是典型的优势菌株。在沙枣苗木菌根化及根瘤化培育过程中,Frankia sp.(H01)和Rhizophagus intraradices可作为重要的候选菌株。

This study was designed to evaluate the diversity of endophytes in Elaeagnus angustifolia L. rootnodules and AM fungi（AMF） in the rhizosphere, located in saline-alkali soil of Heilongjiang Province. Noduleslicing and wet sieve methods combined with molecular biology technology were used to separate, identify andanalyze the endophytes and AMF. In total, 27 endophytic strains were isolated and identified, including 4actinomycetes, 14 bacteria and 9 fungi. The diversity index of endophytic bacteria was the highest while that ofthe endophytic actinomycetes related to root nodule formation was the lowest. The dominance index andevenness index of Frankia sp.（H01） were both higher than that of others. In addition, 8 strains AM fungibelonging to 5 different genus were obtained in the rhizosphere. Glomus contained 3 strains, Funneliformis contained 2 strains, Septoglomus contained 1 strain, Rhizophagus contained 1 strain, and Acaulospora contained 1 strain, respectively. Rhizophagus intraradices was the dominant AMF spore with 100% isolationfrequency in all soil samples and its spore density was 48.5/50 g. As a result, R. intraradices could be used asan important candidate strain in the process of mycorrhizal seedling and nodulating cultivation of Elaeagnus angustifolia L..