Gas exchange and photochemical efficiency of guava under saline water irrigation and nitrogen-potassium fertilization

ABSTRACT The objective of this study was to evaluate the effects different combinations nitrogen and potassium fertilization on gas exchange chlorophyll a fluorescence in seedlings guava cv. Paluma irrigated with water salinity levels. experiment set up randomized block design analyzed 5 × 4 factorial scheme, four replicates. treatments were composed combination factor electrical conductivity irrigation - ECw (0.3, 1.1, 1.9, 2.7, 3.5 dS m-1), (C) formed from recommended doses (N) (K2O), 70% N + 50% K2O, 100% 75% 130% 160% 125% K2O. K2O mitigated salt stress mean 1.3 m-1, resulting increments CO2 assimilation rate, transpiration, instantaneous carboxylation efficiency, electron transport rate. For maximum quantum efficiency photosystem II, only treatment m-1 under showed damage photosynthetic apparatus.