Initial growth of assai seedlings, under different shade levels

Abstract

The açai (Euterpe oleracea Mart.) is an Amazonian species, with the state of Pará being the main center of natural dispersal and the largest producer of fruit. Studies on the physiology of the species, especially in the seedling stage, are still scarce. The objective of the present study was to evaluate the initial growth of açai seedlings under different levels of shading. The seedlings, obtained from seeds, were transplanted into black polyethylene bags containing commercial substrate and maintained in a nursery at 50% shade for 30 days until they became established. Then the treatments 0% - full sun, 30%, 50% and 70% shading were applied. The experimental design was entirely randomized with four treatments (shading levels) and twelve repetitions. After one hundred days, height (cm), diameter (cm), number of leaves, root length (cm), root dry biomass (g), aboveground biomass (g) and total biomass (g), leaf area (cm²) and chlorophyll content were evaluated. Data were subjected to analysis of variance followed by regression analysis if significant by the F test. The height, number of leaves, accumulation of root, aboveground and total dry biomass and leaf area increased with increasing shading level, being superior in 70%. The diameter and length of the roots did not show significant difference while the relative chlorophyll content reduced after 30% of shading.  The açai seedlings responded favorably to shading, suggesting 70% the most suitable for seedling production in the nursery.