Impact of gibberellic acid and prohydrojasmon treatments on fruit characteristics, carotenoid biosynthetic gene expression, and electrical properties in satsuma mandarin fruit
摘要
The increase in temperature and precipitation during autumn and winter has led to a higher incidence of rind puffing in satsuma mandarins, complicating long-term storage. The combined application of gibberellic acid (GA) and prohydrojasmon (PDJ) effectively reduces rind puffing and is widely used in agriculture. This study aimed to investigate the effects of GA and PDJ on carotenoid metabolism-related gene expression, electrolyte leakage, and the correlation between electrical properties, firmness, and puffiness. Here, 12-year-old ‘Aoshima’ satsuma mandarins were treated with a mixture of GA (25 mg L−1) and PDJ (100 mg L−1) denoted as GP, only GA (25 mg L−1), only PDJ (100 mg L−1), and the control. Fruits were harvested on November 16 for gene expression analysis, and on November 28 for quality assessment and electrical property measurements using an LCR meter. The expression levels of CitZ-ISO and CitCYb2 in the GP, GA, and PDJ treatments were significantly lower than those in the control treatment (P < 0.05). Additionally, the expression of CitZDS in the PDJ treatment, as well as CitHYb and CitNCED2 in the GP and PDJ treatments, was significantly lower than in the control (P < 0.05). The GP treatment resulted in significantly higher fruit firmness and specific gravity compared to the control but lower soluble solid content (P < 0.01). The GP group also demonstrated the lowest ion leakage rate and the highest chlorophyll content (P < 0.05). Significant correlations were found between fruit-specific gravity and electrical parameters and between firmness and some electrical parameters at 2 kHz (P < 0.05). Our methods combined plant growth regulators with non-destructive electrical testing and could be used to reduce rind puffing during storage, which could increase fruit production and distribution stability.