Effect of inoculation with arbuscular mycorrhizal fungi on growth of Catalpa bungei

Background: Catalpa bungei is a well-known, valuable, ornamental, high-quality timber tree traditionally cultivated in China because of its excellent quality, decay resistance, wide applicability, and attractive form. The aim of this study was to evaluate the effects of inoculation with arbuscular mycorrhizal fungus (AMF) on the transplant survival rate and growth of C. bungei seedlings under greenhouse conditions. Methods: Two treatments were applied in a completely randomized experimental design: inoculation with Rhizophagus intraradices, and, as a control, soil without inoculum. Results: Four months after inoculation, AMF had colonized 76.05% of plant roots and significantly improved plant growth. With the establishment of the symbiotic relationship, AMF inoculation significantly improved the seedling transplant survival rate by 20%, promoted major growth traits (plant height, basal diameter, leaf area, and specific leaf area), accelerated biomass accumulation (roots, stems, and leaves), and changed the biomass allocation patterns. In addition, compared with non-inoculated treatments, inoculation with AMF increased photosynthetic parameters and chlorophyll contents, elevated major root morphological parameters, changed the proportion of particle sizes of soil micro-aggregates, and promoted the accumulation of nutrients in roots and leaves. Conclusions: The effects on transplant survival, growth and development were more pronounced in C. bungei seedlings inoculated with R. intraradices. Mycorrhizal seedlings of C. bungei can therefore be widely applied in plant transplantation and production practices.