SILVA FILHO, A. M.; http://lattes.cnpq.br/4978983796827788; SILVA FILHO, Antonio Manoel da.
Résumé:
The use of saline waters in the cultivation of West Indian cherry (Malpighia emarginata) in the
semiarid region of Northeastern Brazil can be made viable through fertilization management,
targeting to minimize the damage caused by saline stress. In this context, the objective was to
evaluate the effect of fertilization with combinations of nitrogen, phosphorus and potassium as
an attenuator of saline stress, on growth, morphophysiology, enzymatic activity, harvest and
post-harvest in West Indian cherry, during the second year of production. The study was
conducted in a randomized block design, in 2 x 10 factorial scheme, with two levels of electrical
conductivity of irrigation water - ECw (0.6 and 4.0 dS m-1), and ten combinations of nitrogen
fertilization (N), phosphorus (P2O5) and potassium (K2O) fertilization: (80-100-100; 100-100
100; 120-100-100; 140-100-100; 100-80-100; 100-120-100; 100-140-100; 100-100-80; 100
100-120; 100-100-140% N-P2O5-K2O), with three repetitions. The growth of new branches of
West Indian cherry cv. Flor Branca, leaf water status, electrolyte leakage, gas exchange,
photosynthetic pigment content, chlorophyll fluorescence, organic and inorganic solutes,
enzymatic activity, production, and post-harvest were evaluated. An interaction was verified
between the electrical conductivity levels of irrigation water and the fertilizer combinations for
relative water content, internal CO2 concentration, CO2 assimilation rate, initial fluorescence,
maximum fluorescence, free amino acids, free proline, activity of superoxide dismutase,
catalase, ascorbate peroxidase, total number of fruits, total fruit weight, average fruit weight,
total titratable acidity, hydrogen potential, total soluble solids, maturation index ratio, vitamin
C, reducing sugars, phenolic compounds, flavonoids, and anthocyanins. In isolation, saline
levels affected the relative water content, the percentage of electrolyte leakage, internal CO2
concentration, stomatal conductance, transpiration, CO2 assimilation rate, instantaneous
carboxylation efficiency, instantaneous water use efficiency, photosynthetic pigments,
chlorophyll fluorescence, soluble proteins, free amino acids, activity of superoxide dismutase,
catalase, ascorbate peroxidase, total number of fruits, total fruit weight, average fruit weight,
equatorial diameter of fruits, total titratable acidity, hydrogen potential, total soluble solids,
maturation index ratio, vitamin C, reducing sugars and flavonoids. The irrigation with the
higher ECw (4.0 dS m-1) compromised the leaf water status, the leakage of electrolytes from
the leaf blade, leaf gas exchange, the content of photosynthetic pigments, the quantum yield of
the photosystem II, the growth of new branches and, consequently, affecting all West Indian
cherry production variables, at 120 days after pruning, during the second year of production.
The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and
catalase (CAT) increased when subjected to salt stress (ECw of 4.0 dS m-1). The combination
of CA5 fertilizer = 100-80-100% of NPK recommendation (200, 24 and 80 g of NPK per plant)
for the second year of production modulates the enzymatic activity of SOD and APX, which
mitigates the impacts of salinity in the West Indian cherry, being an efficient choice to preserve
its redox homeostasis under saline stress.
