ABSTRACT
The objective of this study was to evaluate the interaction between water salinity and doses of nitrogen and phosphorus on chlorophyll a fluorescence and on the growth of West Indian Cherry (‘acerola’) plants in the initial growth stage. The research was carried out in a protected environment, in lysimeters filled with Regolithic Neosol of loamy clay texture and low initial phosphorus content. The experiment was conducted in a randomized block design, arranged in a factorial scheme with two factors, five levels of electrical conductivity of the irrigation water - ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four proportions of the recommendation of phosphorus/nitrogen - P/N (100:100, 140:100, 100:140 and 140:140% P/N of recommendation), with three replicates, and each plot consisted of one plant. Water salinity above 2.2 dS m-1 decreases the quantum efficiency of photosystem II and the growth of west indian cherry plants. Increase in nitrogen and/or phosphorus supply improves the energy stability of west indian cherry plants by reducing the effects of salt stress on the quantum efficiency of photosystem II. The increase of 40% in the nitrogen dose increased the chlorophyll a fluorescence, but did not influence the plant growth.
Key words:
chlorophyll fluorescence; saline stress; fertilization; Malphigia emarginata
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** and * - Significant at 0.01 and 0.05 probability levels, respectively; NS - Not significant. Same letters do not differ by Tukey test at 0.05 probability level
* and NS = Significant at 0.05 probability level and not significant, respectively