Applications of 5-aminolevulinic acid on the physiological and biochemical characteristics of strawberry fruit during postharvest cold storage

The compound 5-aminolevulinic acid (ALA) is a key precursor in the biosynthesis of porphyrins, such as chlorophyll, heme and phytochromobilin, and has multiple physiological effects on plants. Varying concentrations of ALA (50mg L-1, 100mg L-1, and 150mg L-1) and water (control) were applied to white stage 'Sweet Charlie' strawberry fruit. All ALA treatments delayed senescence and improved the qualities of strawberries fruit during storage. Among the treatments, 150mg L-1 ALA was the most effective dosage concentration. Exogenously applied ALA significantly reduced the decay index, respiration rate, O-2(-) production rate (O-2(-)), H2O2 and malondialdehyde (MDA) content, increased superoxide dismutase (SOD), ascorbate peroxidase activities (APX), total soluble solids (TSS) content, titratable acidity (TA) and anthocyanin content during the initial stage of storage. These results supported the pre harvest application of ALA as a beneficial strategy for the prevention of postharvest decay of strawberry fruit.