Can prolonged conditions of water deficit alter photosynthetic performance and water relations of coffee plants in central-west Colombia?

Abstract

In the coffee-growing areas of Colombia, the vulnerability of soils to conditions of water deficit has been determined and this limitation has been projected to increase its intensity and severity during extreme climatic scenarios, which constitute one of the factors limiting coffee production. The objective of this study was to evaluate the effect of prolonged water deficit conditions on the physiological performance of coffee plants cv. Castillo ®. The evaluations were carried out in 13-month-old “Castillo®” variety plants established in a greenhouse which were subjected to two conditions: well-watered at field capacity and water deficit in the soil-applied through withholding the water supply for 40 days, using a completely randomized experimental design. Leaf water potential (Ψpd and Ψmd), gas exchange, and chlorophyll fluorescence parameters (Fv/Fm and ETR) were measured. In the plants with water deficit, Ψpd and Ψmd were decreased significantly. Five days after restricting the water supply, the gs was significantly reduced to 95% at the end of the experiment compared to plants without stress. The Fv/Fm and ETR parameters showed no sensitivity under the water deficit conditions. Plants under water deficit decreased Amax by 81%, Isat by 61%, and Rd by 50%, as compared to plants without stress. The transpiration and water-use efficiency decreased, while Ci had a greater concentration in plants under water deficit. These results indicate the physiological performance coffee cv. Castillo ® plants were significantly affect by prolonged conditions of soil water deficit and that the reductions in photosynthetic processes were related to stomatal limitations.