Fisiologia do maracujazeiro BRS GA1 sob estratégias de irrigação de água salina e adubação potássica.

Abstract

The use of water salinity management strategies and potassium fertilization is an alternative capable of minimizing the deleterious effects of salt stress on sour passion fruit plants. In this context, the objective was to evaluate gas exchange and photosynthetic pigments of passion fruit cv. BRS GA1 depending on the application of saline water, varying the stages of development and potassium fertilization. The research was conducted in the field at the Experimental Farm 'Rolando Enrique Rivas Castellón', belonging to the Agro-Food Technology Science Center of the Federal University of Campina Grande, in São Domingos, PB, using a randomized block design, in 6 x 2 factorial scheme, whose treatments were constituted by the combination of two factors: irrigation strategies with saline water and two potassium doses (60 and 100% K2O of the fertilizer recommendation for the crop), with four replicates , with each plot consisting of 3 plants, making a total of 144 experimental units. The levels of chlorophyll a, chlorophyll b, stomatal conductance and leaf transpiration of 'BRS GA1' passion fruit are reduced with irrigation with water of 4.0 dS m-1 in all salinity management strategies. Fertilization with 60% of the K2O recommendation attenuated the effect of saline stress on the CO2 assimilation rate and instant efficiency in the use of passion fruit water 'BRS GA1'. The successive application of saline water in the vegetative and flowering phase and vegetative and fruiting is harmful to the carotenoid contents and the internal CO2 concentration of the passion fruit, regardless of the K2O dose.