Unraveling the mechanisms behind salt stress alleviation and enhanced fruit storability in pomegranate through triacontanol treatment

Abstract

Salt stress is a significant factor that leads to various detrimental effects on pomegranate trees. This study was undertaken with the primary objective of developing a treatment strategy aimed at mitigating the adverse impacts of salinity in fields, and its negative reflections on the post-harvest quality of pomegranate fruit. At the commencement of the study, we utilized response surface methodology (RSM) to assess a range of triacontanol (TRA) concentrations along with different spray frequencies. Our investigation revealed that applying 10 and 20 µM TRA three times proved to be the most effective treatments. Accordingly, the effect of these concentrations was studied in depth. The treatment with TRA at concentrations of 10 and 20 µM demonstrated significant positive effects. TRA effectively mitigated the harmful impacts of salinity, preserved the plant's nutrient and antioxidant content, and led to an increase in productivity. Moreover, TRA treatments had a notable effect on enhancing post-harvest storability of fruits during storage at 5 ̊C and 90 % RH for 12 weeks. TRA treatments resulted in higher concentrations of mineral nutrients (N, P, K, and Ca), porphyrin concentration, relative water contents, activities of CAT, POD, and SOD, glycine betaine, proline, amino acids, total phenolics, and total carbohydrates, additionally, TRA treatments led to increased fruit weight and fruit yield compared to the control group. Moreover, TRA treatments attained lower hydrogen peroxide, membrane permeability, malondialdehyde, Na, and Cl compared with control. Indeed, the positive effects of TRA treatments extended to fruit storability. TRA treatments resulted in a notable decrease in the percentage of decay, weight loss, and softness. Furthermore, TRA treatments demonstrated efficacy in preserving TSS, husk color, ascorbic acid, and anthocyanin content in the arils. These combined benefits highlight the potential of using TRA as a practical and effective method to alleviate salt stress and enhance pomegranate fruit storability.