Ecophysiology in the 'Tommy Atkins' mango under different water regimes and light availability.
Almeida E. I. B., Celin E. F., Freire A. G., Lacerda C. F. de, Bezerra M. A., Mesquita R. O.
Author Affiliation: Empresa Brasileira de Pesquisa Agropecu醨ia (Embrapa - Roraima), Bras韑ia, DF, Brazil.
Agro@mbiente On-line 9 : 251-260
Abstract : The interaction between water deficit and the poor use of light radiation by plants can result in a reduction in gas exchange with a consequent reduction in growth and production. In the 'Tommy Atkins' mango, studies of this interaction are rare. Given the above, the aim was to evaluate ecophysiological variables in leaves of the 'Tommy Atkins' mango subjected to varying conditions of lighting and water regime in the canopy, at different times and under semi-arid conditions. The data were analysed in a completely randomised design, arranged in 3 split lots, with three replications. The first, second and third lots were represented by the water regime, position in the canopy and time of evaluation respectively. The variables for net carbon assimilation (A), stomatal conductance to water vapour (gs), transpiration (E), leaf temperature (Tf), air temperature (Ta) and vapour pressure deficit (VPD) were all measured in an open system, under artificial light and ambient CO2 concentrations, using the IRGA. The results showed that the interaction between water regime, position in the canopy and time of evaluation affect ecophysiology in the 'Tommy Atkins' mango. Leaves in the centre of the canopy (with less light) show reduced capacity for production compared to the other leaves. Plants grown under a water regime of 50% display greater water use efficiency, especially during the most adverse environmental conditions (0900 to 1300). The efficient management of water conditions and leaf position in the canopy can positively affect gas exchange and consequently, growth and production.