Abstract

This study aimed to evaluate the interaction between the fertilization with nitrogen (N) and phosphorus (P) and irrigation with saline water on the water relations, gas exchanges and chlorophyll a fluorescence in West Indian cherry in the vegetative stage. The study was carried out in protected environment, using lysimeters filled with clay loam Regolithic Neosol, with low P content, installed in a randomized block design, arranged in a factorial scheme with five levels of electrical conductivity of irrigation water (ECw), and four managements of P and N fertilization, with three replicates and one plant per plot. Along the experiment, water relations, gas exchanges and chlorophyll a fluorescence were evaluated in West Indian cherry plants. The increase in irrigation water salinity reduces the gas exchanges of the plants, but the increment of 40% in N supply increases the photosynthetic activity of West Indian cherry at recommendation levels higher than 100:100% of the P/N ratio, when irrigated with ECw of up to 3.0 dS m^-1. The combined action of N and P, at doses of 140:140% N/P recommendation, increases leaf turgor in the plants, regardless of the ECw level. The increment of 40% in N dose reduces the effects of salinity on the initial fluorescence of chlorophyll a in West Indian cherry irrigated with up to 2.2 dS m^-1.

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