LEAF GAS EXCHANGE AND EFFICIENCY OF PHOTOSYSTEM II IN ADULT PLANTS OF SIX FOREST SPECIES AS FUNCTION OF THE WATER SUPPLY IN THE SOIL

The reduction of water availability causes effects on photosynthesis and the development of tree species. The objective of this study was to evaluate leaf gas exchange and photochemical efficiency of photosystem II in adult plants of goncalo-alves (Astronium fraxinifolium Schott), guanandi (Calophyllum brasiliense Cambess.), ipe-amarelo (Handroanthus serratifolius (Vahl.), ipe-rosa (Handroanthus impetiginosa (Mart.) Matos.), marupa (Sima roubaamara Aubl.) and mogno (Swietenia macrophylla King.) cultivated in non-irrigated and irrigated conditions, in the Irrigation Perimeter of Baixo Acarau, Ceara, Brazil. The experimental design was a repeated measures, a scheme of split-plots (6 x 2 x 3), with the plot composed by six plant species, the subplot by two water regimes (irrigated and non-irrigated) and the sub-subplots by evaluation dates. The measurements of leaf gas exchange were made in 11/22/2012 (dry season), 02/07/2013 (date that preceded the rainy season) and 05/17/2013 (rainy season). The species mogno, guanandi and ipe-amarelo were more sensitive to drought compared to other species, evidenced by greater reductions in leaf gas exchange and photochemical efficiency of photosystem II. The ipe-rosa, marupa and goncaloalves were more adapted to conditions of low soil water availability.