三种石斛菌根形态结构及元素构成的研究

通过对石斛菌根解剖镜检表明 :石斛菌根是由根被、皮层、中柱组织构成 ,在皮层细胞内 ,常有菌根真菌栖居、生长 ,并呈现菌丝团结构。对石斛组培非菌根与野生石斛菌根营养元素分析表明 ,组培根N、P、K含量是菌根的 2 5倍 ;微量元素除Zn外 ,Cu、Fe、Mn、Ca、Mg等元素含量低于菌根 2 2 % 78%。

石斛菌根菌复合菌剂的研制及应用

选用木霉菌(Trichoderma)的F35菌株、石斛小菇(Mycena dendrobii Fan et Guo)的F48菌株和石斛生长需要的营养元素,研制出石斛菌根菌复合菌剂,并确定了石斛菌根菌复合菌剂的保存期及最适用量。金钗石斛组培苗的移栽结果表明,经石斛菌根菌复合菌剂处理的金钗石斛组培苗干重比对照提高29.03%,比单一菌剂提高8.11%～17.65%;石斛多糖含量比对照提高85.29%,比单一菌剂提高14.55%～50.00%;总生物碱的含量比对照提高16.30%,比单一菌剂提高4.90%～11.46%。

Inoculation Effects of Dendrobium officinale Mycorrhizal Fungi on Their Plantlets

[Objective] This study aimed to explore the inoculation effects of Dendrobium officinale mycorrhizal fungi on their plantlets. [Method] Endophytic strains Tj1, Tj2 and Tj3 were obtained by isolation and purification from mycorrhiza of wild Dendrobium officinale and inoculated on the root system of Dendrobium officinale for inoculation test. [Result] Under tissue-culture conditions, at early stage, Tj1 strain hadn＇t shown promotion effect on Dendrobium officinale, Tj2 strain had shown relatively strong promotion effects, and Tj3 strain had promoted the growth of roots; at late stage, Tj1 strain had shown relatively strong promotion effects, Tj2 strain had shown the best inoculation effects and the strongest promotion effects, while Tj3 strain had caused root and seedling rot problems of the plantlets; under outdoor conditions, after inoculation with Tj2 strain, the number of leaves and lateral buds were increased, the growth of lateral root and the increase of plant height were significant, the leaves of Dendrobium officinale plantlets were large and dark green and an obvious root enlargement phenomenon was observed. [Conclusion] The two inoculation methods both indicate that Tj2 strain has relatively strong promotion effects on the growth of Dendrobium officinale roots and shoots, the increase of plant number and plant height, and the germination of new shoots and roots, which proved the effective establishment of symbiotic relationship between Tj2 strain and Dendrobium officinale. Therefore, T2 strain has practical application values on the successful cultivation of Dendrobium officinale plantlets.

Phylogenetic constrains on mycorrhizal specificity in eight Dendrobium(Orchidaceae) species

Plant phylogeny constrains orchid mycorrhizal(OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species,and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota(9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.