Seaweed-based biostimulants improves quality traits, postharvest disorders, and antioxidant properties of sweet cherry fruit and in response to gibberellic acid treatment

Abstract

The main aim of this research was to determine whether seaweed-based biostimulants (BIO) have the potential to offset the delaying of fruit maturation and improve fruit quality and antioxidant properties in gibberellic acid (GA3)-treated cherries. Compared to the control, 5 g L−1 BIO applied twice at pit hardening (PH) and straw color (SC) or 3 times at PH, SC, and 1 week before harvest (1WBH) in mid-maturing ‘Bing’ cherries accelerated color development, increased soluble solids content (SSC), titratable acidity, total phenolics (TP), and DPPH radical scavenging activity at harvest. However, these treatments resulted in smaller and softer fruit. For late-maturing ‘Lapins’ cherries, BIO had no effect on fruit coloration, but increased the levels of antioxidants and antioxidant capacity at harvest, especially in 3 applications. Spraying 5 g L−1 BIO 3 times plus a single application of 10 mg L−1 GA3 at PH on ‘Bing’ cherries effectively increased fruit firmness (FF) and size, but showed a strong delaying effect on color development and SSC at harvest, and reduced resistance to disorders after 4 weeks of storage at 0°C if the combination-treated fruit were late harvested. Decreasing GA3 concentration from 10 to 5 mg L−1, increasing BIO concentration from 5 to 10 g L−1, and extending the harvest date by 5 d could impair the delaying effect of GA3 on fruit maturation, restore the normal fruit size, reduce the rates of decay, stem browning (SB), and surface pitting (SP), and maintain high FF and DPPH radical scavenging activity. In conclusion, pre-harvest 3 applications of 10 g L−1 BIO and 5 mg L−1 GA3 once at PH have the potential to curtail the GA3’s inhibition on fruit maturation, extend the harvest window, improve fruit quality, and increase antioxidants and antioxidant capacity in ‘Bing’ cherries.