Article,
LEAF CONCENTRATIONS OF NITROGEN AND PHOSPHORUS IN Phaseolus vulgaris L. PLANTS UNDER HIGH CO2 CONCENTRATION AND DROUGHT STRESS
ENGENHARIA AGRICOLA, (September 2014)
Abstract
This study aims to evaluate the leaf concentration of nitrogen and phosphorus correlated to the production of photoassimilates in beans plants (Phaseolus vulgaris L.) under high CO2 and drought stress. The experiment was conducted in Vicosa (Brazil), during the period from April to July 2009, by using open-top chambers equipped with CO2 injection system. The drought stress was applied, through the irrigation suspension, during the period from flowering to maturation. The experimental design was randomized blocks in split-plot scheme with four replication, where the plots with plants grown in CO2 of 700 mg L-1 and CO2 environment of 380 mg L-1 and the subplots with plants with and without drought stress. The results were submitted to ANOVA and Tukey test (p < 0.05). In the plants under high CO2 with and without drought stress, the photosynthetic rate increased by 59\%, while the dry matter presented an increment of 20\% in the plants under high CO2 without drought stress. Reductions in N and P occurred in plants grown under high CO2, resulting in greater efficiency in nitrogen use for photosynthesis. The high CO2 increase only the total dry matter and not the total mass of grains. The drought stress reduces the dry matter and mass of grain, even at high CO2.
