PHOSPHATE AND INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI ON THE GROWTH OF Cecropia pachystachya (Trec) SEEDLINGS

Abstract

The objective of this study was to evaluate the effect of the inoculation with arbuscular mycorrhizal fungi (FMA) in different levels of P₂O₅ on the growth of Cecropia pachystachya seedlings in the field. The study consisted of a 5x2 factorial with five levels of P₂O₅ (zero, 85, 170, 255 and 340 mg.kg^-1), with and ithout inoculation with a mixture of FMA. It was used four replications, each one with twelve seedlings. The seeds were sowed in plastic tubes with capacity of 50 cm³ of substratum and stored for 120 days. After this period the seedlings were transplanted to the field, where they remained for another 150 days. Seedling diameter and height were measured at 60 and 120 days, aerial part and root dry matter, and arbuscular mycorrhizal colonization. Diameter, height, leaf area, aerial part dry matter and the number of surviving seedlings were determined after 150 days. None of the factors tested had any effect on seedling growth with one exception; inoculated plants with FMA had more root dry matter. Plants inoculated with smaller doses of P₂O₅ showed a larger percentage of surviving individuals and more vigorous seedlings. Results suggest that in low fertility soils of and subject to the hydric stress the C. pachystachya seedlings should be inoculated with FMA.

KEY-WORDS: Native vegetation; mycorrhiza fungi; native species; seedling production; inoculation.