Exogenous γ-aminobutyric acid can alleviate the adverse effects of seed aging on fatty acids composition and heterotrophic seedling growth in medicinal pumpkin

Accelerated oil oxidation and degraded fatty acids (FA) composition are considered as well-known consequences in oilseed crops resulting from the imposed aging conditions. Hence, evaluating the effective techniques and understanding the biological mechanisms associated to mitigating seed deterioration process in medicinal pumpkin (Cucurbita pepo subsp. Pepo. Convar. Pepo var. styriaca Greb) may be necessary. In the current study, different durations of artificial accelerated aging (0, 48, 72, and 96 h) and priming solutions (water priming as control and.-aminobutyric acid (GABA) priming at 1, 2, and 3 mmol L-1) were tested. From the results, a significant decrease in oil percentage and seedling dry weight was observed with increasing seed aging duration, whereas malondialdehyde content and electrolyte leakage significantly increased. Moreover, with increasing seed deterioration severity, percentage of saturated FA (SFA) significantly increased, while mono- and polyunsaturated FA (MUFA and PUFA) decreased. In contrast, GABA priming alleviated the deleterious effects of seed deterioration on seedling growth and FA composition. For instance, after 96-h aging period, GABA priming at 3 mmol L-1 decreased SFA/MUFA and SFA/PUFA by 14.2 and 13.3%, respectively, compared with control. Overall, the results obtained here may confirm the crucial role of GABA priming to improve the successful establishment of seedlings raised from medicinal pumpkin seeds.