Co-Inoculation with Beneficial Soil Microorganisms Promoted Growth and Quality of Tabebuia rosea Seedlings

Poor seedling quality is a major limiting factor for the success of commercial afforestation and ecological restoration in the tropics. This is commonly due to poor nutrient availability of soil-based substrates used for seedling growth. Currently, the use of biofertilizers has gained attention as a biotechnological tool to overcome plant malnutrition and enhance seedling quality from the nursery. The aim of this study was to evaluate the effects of individual and combined inoculation with selected beneficial soil microorganisms on plant growth of Tabebuia rosea (Bertol.) Bertero ex A.DC. in the nursery stage. For this purpose, individual, dual, and triple inoculations were conducted with Rhizoglomus fasciculatum (arbuscular mycorrhizal fungus: AMF), Mortierella sp. (mineral-solubilizing fungus: MSF), and Azospirillum brasilense (plant growth-promoting bacteria: PGPB). After six months, the inoculation with PGPB significantly promoted plant growth over the uninoculated control. Dual inoculation with AMF+MSF and AMF+PGPB had lower but significant effects over the control. The results showed that biofertilization is an effective alternative to promote plant growth and quality of this species in the nursery and thus to produce better plants for forestry and ecological restoration in tropical areas.