【摘要】 菌根在兰科的生命周期和进化史上起着关键作用。兰科中大多数是附生兰,但它们的菌根研究相对缺乏。为了探讨菌根对附生兰的影响,本研究用金钗石斛(Dendrobium nobile)与通过形态学特征和分子生物学鉴定的分属于瘤菌根菌属(Epulorhiza)的S1和胶膜菌属(Tulasnella)的S3真菌共培养。共培养结果表明,S1和S3与金钗石斛形成了共生关系,且不同程度地促进了其生长。15N稳定同位素标记实验证实,S1菌株显著促进了金钗石斛对有机氮的利用,而S3菌株没有显著的促进作用。同时,S1和S3真菌均能提高金钗石斛中石斛碱的含量。研究结果表明,菌根真菌能促进附生兰幼苗的生长、有机氮的利用和次生代谢产物的积累。更多还原

【Abstract】 Mycorrhizal associations play a key role in the life cycle and evolutionary history of orchids. Although most orchid species are tropical and epiphytic,their mycorrhizae are poorly understood compared with those of temperate,terrestrial orchids. To investigate the influences of such fungi on photosynthetic,epiphytic orchids,we inoculated seedlings of Dendrobium nobile with Epulorhiza sp.( S1) or Tulasnella sp.( S3). These fungi had been identified based on their morphological and molecular characters. Both S1 and S3 formed symbiotic associations with our seedlings,promoting their growth and development to various degrees. Results from signature experiments with the15N stable isotope suggested that the utilization of organic nitrogen by orchid seedlings was significantly improved by S1,but not by S3. Dendrobine contents were significantly higher in all inoculated seedlings. Our findings demonstrate that these mycorrhizal fungi enhance plant growth,their utilization of organic nitrogen,and the accumulation of secondary metabolites in this epiphytic orchid species.更多还原