Light-curve responses in Atriplex nummularia L. irrigated with saline water

Abstract

Atriplex nummularia L. is one of the most studied halophytes in research on phytoremediation of salt-affected soils. However, the optimization of biomass requires studies that indicate the appropriate way to evaluate the photosynthesis. The objective of this study was to investigate the photosynthetic efficiency of Atriplex irrigated in order to indicate the best range of photosynthetically active radiation (PAR) that should be used . Atriplex were subjected to daily irrigations (0, 50, 100, 200, 250 and 300 mmol L^-1 of NaCl). The light curves were determined at 15 and 84 days applying twenty light intensities (2000, 1750, 1500, 1250, 1000, 750, 500, 250, 200,175, 150, 125, 100, 75, 50, 25, 15, 10, 5, 0 μmol m^-2 s^-1PAR). The highest values of photosynthesis rate were observed at PAR of 2000 μmol m^-2 s^-1 and of 800 μmol m^-2 s^-1 to 15 and 84 days of evaluation, independent of the NaCl. The present study provides data that support the choice of the ideal PAR in evaluations of gas exchange in Atriplex.