CO2 capture and water use efficiency in Opuntia stricta (Haw.) at different seasons and evaluation times

The forage cactus Mexican Elephant Ear is widely incorporated into the animal productive chain of northeast region Brazil. However, there a lack studies on physiological dynamics this cactus. Therefore, study was conducted at Estação Experimental Prof. Ignácio Salcedo Instituto Nacional do Semiárido (INSA), in Campina Grande, State Paraíba, aim to evaluate CO2 uptake and water-use efficiency levels Opuntia stricta (Haw.) during different seasons evaluation times. treatments were distributed using 24×2 factorial arrangement, which corresponded gas exchange processes for 24 hours rainy (June) dry (December) seasons. evaluated parameters stomatal conductance, transpiration rate, internal concentration, instantaneous intrinsic efficiency. results revealed that more intense season, with good stability, than low season. Regardless peaked between 24:00 02:00. In addition, range time most suitable conduct analyses under field conditions.