Methodology for water potential measurement on mango using the pressure ayamber

A study was carried out to verify the application of a simple approach for water potential evaluation on mango (Mangifera indica, L). Data were collected on mango "Tommy Atkins", cropped under drip irrigation condition, at Embrapa Semi-Arido, Petrolina-PE., Brazil. Data were obtained with a pressure chamber and correlated with psychrometric chamber measurements. Chamber pressure was halted at each 0.1 MPa for sap sampling with filter paper for differentiation between the resin and water outflow. Resin exudation was distinguished by the appearance of dark dots on the paper. The results showed that there was no correlation between the methods at 1 % probability level when the values obtained at the moment of resin exudation were used. However, data obtained at the moment of water outflow were significantly correlated through the equation Y= 0.1678 + 1.151 (X) and R= 0.98 **. The results suggest that the use of filter paper to detect the moment of water outflow may help obtaining accurate pressure chamber water potential measurement on mangoes.