Application of oxalic acid to sweet cherry trees improves yield, quality and phytochemical attributes at harvest
Two cultivars of sweet cherry trees ('Sweet Heart' and 'Sweet Late') were treated with oxalic acid at three physiological stages: at pit hardening, initiation of colour changes and initiation of maturity. Three oxalic acid concentrations (0.5, 1 and 2 mM) were foliar-sprayed compared with control (irrigation water). Along the growing cycle fruit samples were taken for determining fruit size, firmness, colour, total soluble solids and total acidity. At time of harvest fruit yield was evaluated for both cultivars as well as the content of bioactive compounds (total phenolics and total anthocyanins) as well as the antioxidant activity from hydrophilic and lipophilic fractions separately. Results showed that oxalic acid significantly increased fruit weight (measured as volume) and yield, the 2 mM concentration being the most effective. In these fruit a profile of phenolic compounds was carried out and results revealed cyanidin 3-glucoside (anthocyanin), myricetin 3-glucoside (flavonol) and neochlorogenic acid (hydroxycinnamic acids) were the major compounds. Moreover, the concentration of these phenolics occurred at higher concentration in treated than in control cherries. In summary, the preharvest treatment with oxalic acid was able to increase fruit production and quality of both 'Sweet Heart' and 'Sweet Late' cultivars.
Zapata, P.J., Castillo, S., Guillén, F., Serrano, M., Martínez-Romero, D., Valverde, J.M., Díaz-Mula, H.M. and Valero, D. (2016). Application of oxalic acid to sweet cherry trees improves yield, quality and phytochemical attributes at harvest. Acta Hortic. 1130, 231-234
Prunus avium L., preharvest treatments, yield, quality, bioactive compounds, antioxidant activity