Índices fisiológicos, crescimento e qualidade de mudas de maracujazeiro sob estresse salino e adubação potássica.

Abstract

The high salt concentrations found in the semiarid waters of Northeastern Brazil stand out as a limiting factor for crop production in this region. In this context, the objective of this study was to evaluate the percentage of cell membrane damage, the photosynthetic pigment contents and the growth of ‘BRS Rubi do Cerrado’ passion fruit plants cultivated with saline water and potassium fertilization during the seedling formation phase. The experiment was conducted in a greenhouse of Universidade Federal de Campina Grande, in Pombal-PB. A randomized complete block design in a 5 x 2 factorial arrangement was adopted, with five levels of electrical conductivity of the irrigation water (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1) and two doses of potassium - DK (50 and 100% of the recommendation of Novais), with two plants per plot and four replications. The dose of 100% recommendation corresponded to 150 mg of K2O kg-1 of soil. Water salinity from 0.3 dS m-1 promoted reduction in chlorophyll a and b synthesis and growth of BRS Rubi do Cerrado purple passion fruit plants at 60 days after sowing. Water with electrical conductivity of up to 3.5 dS m-1 can be used to form passion fruit seedlings of acceptable quality for the field. Potassium doses did not attenuate the deleterious effects of salt stress on the formation of passion fruit seedlings of ‘BRS Rubi do Cerrado’.