Effects of Bamboo Forest Type and Density on the Growth of Bletilla striata and Root Endophytic Fungi

Abstract

Bletilla striata is a terrestrial orchid with high ornamental and medicinal values that is widely interplanted in bamboo forests. However, little is known about the effects of bamboo forest type and density on the growth of B. striata and its symbiotic relationship with root endophytic fungi. In this study, the growth state of B. striata, the community composition and diversity of its root endophytic fungal, and the fungal nutritional function were investigated in Phyllostachys edulis, P. iridescens and P. glauca forests with three densities. We found that the type and density of the bamboo forest had significant effects on the growth of B. striata, with the biomass, leaf width, root quantity and width being the highest in the low-density of the P. edulis forest. The community composition and abundance of root endophytic fungi in B. striata varied among different bamboo forests and densities, with P. edulis and P. iridescens forests dominated by Basidiomycota and Serendipita, while P. glauca prevailed by Ascomycota and Dactylonectria. The trophic modes of root endophytic fungi were also affected by forest types and densities. The abundance of symbiotroph fungi was the highest in P. edulis and P. iridescens forests and greatly varied with density gradient, and saprotrophic fungi comprised the highest proportion in the Ph. glauca forest. These results provide basic data for further research and the configuration between bamboo species and terrestrial orchids.