Postharvest Treatments with Naphthalene Acetic Acid and Methyl Jasmonate to Maintain the Quality of 'Laetitia' Plums (Prunus salicina Lindl.) during Cold Storage

Aims: This work aimed to verify the efficiency of the phytoregulators naphthalene acetic acid (NAA) and methyl jasmonate (MeJa) in maintaining the postharvest quality of 'Laetitia' plum fruits, stored under refrigeration.

Study Design: The experimental design used was completely randomized with three treatments and five repetitions of 30 fruits/repetition.

Place and Duration of Study: The experiment was carried out with 'Laetitia' plums from a commercial orchard in the municipality of Catanduvas, SC (27° 4' 3'' S and 51° 39' 47'' W), during the 2017/18 harvest.

Methodology: The fruits were treated with distilled water (control), MeJa (10-4 M), and NAA (10 mg. L-1); and stored in chambers with Biochemical Oxygen Demand (BOD), maintained at a temperature of 4±1°C and relative humidity of 85±3%, for 35 days and another three days at ambient conditions (23±1°C). The main quality attributes were evaluated after storage.

Results: Weight loss, soluble solids content, and pulp firmness are not affected by the application of phytoregulators. The application of NAA 10 mg.L-1 accelerated fruit ripening and showed no positive effects. Treatment of 'Laetitia' plums with MeJa 10-4 M decreases ethylene production, respiration, and lipid peroxidation. This treatment also increased the concentration of antioxidants and total phenolic compounds. Fruit treatment with MeJa 10-4 M significantly reduced the incidence and severity of internal browning of the 'Laetitia' plum.

Conclusion: The treatment of 'Laetitia' plums with MeJa 10-4 M has positive effects on post-harvest storage, mainly reducing internal browning.