Growth and nutrient use efficiency were determined for Euterpe edulis Mart. seedlings grown under two levels of irradiance 2% and 50% of full sun, with the peak radiation flux values of 36 and 900 µmol de fótons m-2 s-1, respectively), and two levels of nitrogen (56,1 and 6,5 mg L-1) and phosphorus (10,0 e 2,0 mg L-1). Seedlings grown under low irradiance supply had less biomass. Higher supply of both nitrogen and phosphorus had a significant effect on total biomass only in plants grown under high irradiance. Only a higher nitrogen supply or only a higher phosphorus supply didn't affect the growth in higher irradiance. Nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE) increased with increased supply of irradiance. NUE increased with low supply of nitrogen. These results suggest that for E. edulis 1) it is unlikely that natural variation in nitrogen or phosphorus availability will affect the growth of seedlings in the understorey environment, as the availability of irradiance rather than major soil nutrients seems to be the limiting factor for the growth of seedlings in this environment, 2) the seedlings can take benefit from gap appearance since they can adjust their growth and nutrient use efficiency when light and nutrient availability are varied, 3) the higher NUE showed by the seedlings under low nitrogen supply can enhance their ability for competition under environments with low nitrogen supply and 4) at a high irradiance the availability of both nitrogen and phosphorus can limit the growth of seedlings in the field.
Euterpe edulis; growth; light; nitrogen; phosphorus
