Initial growth and chemical composition of pornuncia plant fertilized with phosphorus and inoculated with arbuscular mycorrhizal fungi

SUMMARY The aim of this study was to evaluate the influence of phosphate fertilization and mycorrhizal inoculation on the initial growth, chemical composition and mycorrhizal symbiosis in Pornuncia (Manihot sp. – Euphorbiaceae) plant. An experiment was conducted in a completely randomized design in factorial arrangement with three concentration of simple superphosphate (P1 – 5.14mg/dm3, P2 – 49.3mg/dm3 e P3 – 98.6mg/dm3) and three inoculation treatments (not inoculated – NI, inoculated with Claroideoglomus etunicatum – CE or GA – Gigaspora albida), in three replications, during 90 days. It was verified that inoculation with CE promoted increase in leaf area and crude protein concentration in Pornuncia plants, while the GA isolate provided higher mycorrhizal colonization and glomerospores number. On the other hand, the addition of superphosphate reduces the mycorrhizal colonization in Pornuncia plants. Although the phosphate fertilization does not affect the growth of Pornuncia plants, the P2 concentration promoted an increase of 15,0% of neutral detergent fiber content. Inoculation with Claroideoglomus etunicatum in Pornuncia plants increases leaf area and crude protein content in the aerial part, and may contribute to the development and improvement of the chemical composition of this forage plant.