Gas exchanges and photochemical efficiency of West Indian cherry cultivated with saline water and potassium fertilization

Adaan S. Dias,Hans R. Gheyi,Geovani S. de Lima,Pedro D. Fernandes,Lauriane A. dos A. Soares,Francisco V. da S. Sá

doi:10.1590/1807-1929/agriambi.v22n9p628-633

Abstract

ABSTRACT The problem of the lack of adequate water resources for agriculture has intensified in recent years, making it necessary to use waters with relatively high concentration of salts for the irrigation of crops all over the world. The objective of this study was to evaluate the influence of potassium (K) fertilization as a salt stress attenuator on gas exchanges and photochemical efficiency of West Indian cherry. The crop was cultivated under greenhouse conditions in the municipality of Campina Grande, PB, in lysimeters filled with 250 kg of sandy loam soil. Treatments were distributed in randomized blocks, in a 2 x 4 factorial scheme, with two levels of electrical conductivity of irrigation water - ECw (0.8 and 3.8 dS m-1) and four K doses (50, 75, 100 and 125% of recommendation), in which the dose corresponding to 100% was equal to 19.8 g of K2O, with three replicates and one plant per repetition. Seedlings of the West Indian cherry cultivar BRS 366-Jaburu, grafted onto a locally developed rootstock from the clonal garden of the EMBRAPA Tropical Agroindustry, Pacajus, CE, were used. Irrigation with salinized water (electrical conductivity of 3.8 dS m-1) compromised the gas exchange and the photochemical efficiency of West Indian cherry plants. Potassium fertilization was not efficient at reducing the stress caused by water salinity on West Indian cherry plants.

Highlights

West Indian cherry (Malpighia emarginata D.C.) is a fruit crop that has stood out as an excellent natural source of vitamin C, besides anthocyanins and carotenoids, compounds with beneficial effects on human health due to their recognized antioxidant action (Maciel et al, 2010)
The cultivation of West Indian cherry becomes highly promising in the Northeast region, having good prospects for the fruit grower market
The experimental design was in randomized blocks, with three replicates, using a 2 x 4 factorial scheme, and treatments consisted of two levels of irrigation water electrical conductivity - ECw (0.8 and 3.8 dS m-1) and four K doses (50, 75, 100 and 125% of recommendation)

Summary

Introduction

West Indian cherry (Malpighia emarginata D.C.) is a fruit crop that has stood out as an excellent natural source of vitamin C, besides anthocyanins and carotenoids, compounds with beneficial effects on human health due to their recognized antioxidant action (Maciel et al, 2010). The cultivation of West Indian cherry becomes highly promising in the Northeast region, having good prospects for the fruit grower market. Despite the good adaptability of West Indian cherry, the Brazilian semi-arid region poses risks to its cultivation, due to the scarcity of water resources, where the available sources of water for irrigation commonly have high concentrations of salts, especially sodium (Jiang et al, 2012; Souza et al, 2017). The excess of salts in the soil causes reduction in the osmotic potential, resulting in water deficit in the crops. This deficit causes stomatal closure, limiting CO2 assimilation and transpiration in plants, and reduces their photosynthetic rate (Silva et al, 2010). Plants subjected to saline stress undergo changes in the functional state of the thylakoid membranes of chloroplasts, which cause alterations in the characteristics of the fluorescence signals (Chaum & Kirmanee, 2011; Silva et al, 2011a; Freire et al, 2014), diminishing growth and yield (Sousa et al, 2012)

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Methods

Results