Seedlings growing in deep shade (2 and 6% of full sun) showed, compared to seedlings growing at higher light levels, lower values of biomass, growth rates, root/shoot ratio, specific leaf weight (SLW), chlorophyll a/b ratio and higher value of leaf area ratio (LAR). With the increase in light availability, plants showed three different responses: 1) up to 20% of full sun, plants showed, with light increase, higher values of biomass, relative growth rate (RGR), unit leaf rate (ULR), root/shoot ratio, number of leaves, chlorophyll a/b ratio and lower values of leaf weight ratio (LWR) and LAR; 2) between 20% and 70% of full sun the seedlings did not show morphological or physiological alterations with increase in light, except higher chlorophyll a/b ratio at higher light levels; and 3) seedlings growing in full sun light showed lower biomass. Seedlings transferred from low to high light showed behavior similar to seedlings growing always in higher light. Stomatal density was slightly higher in plants transferred to higher light levels. Lower growth in deep shade and increase in growth with increasing light up to 20-30% of sun light may indicate that the regeneration of this species can take advantage of the appearance of a clearing. The lower performance in full sun and in deep shade may indicate limited competitive capacity of the species in large clearings and in very closed canopies.
light acclimation; Euterpe edulis; growth
