Crocus sativus L. (saffron): A cocktail of bioactive molecules as a biostimulant by influencing plant growth, the polyphenol and ascorbic acid content of eggplant fruit

This study aims to valorize saffron by-products and use them as biostimulants in agricultural practices against chemical products. For this, different treatment of the aqueous extract of the stigmas, tepals and stamens: STS = 1 g/L stigma + 1 g/L tepal + 1 g/L stamen, TS = 2 g/L tepal + 0.6 g/L stigma, ST = 1 g/L stigma + 1 g/L tepal, S = 1 g/L stigma, SS = 1 g/L stigma + 1 g/L stamen, T = 2 g/L tepal, are used as foliar treatment, seven times every fortnight during the cycle, in a complete random block, on eggplant plants in greenhouse conditions, to know their effect on plant growth and composition fruit biochemistry. The STS, S, and T treatments significantly (p ≤ 0.05) improved plant height compared to the other treatments and the control. Then, the T and S treatments significantly (p ≤ 0.05) improved the polyphenol contents (flavonols and anthocyanins). In contrast, the highest values are observed in the fruits of the plants receiving the T, S, and ST treatments for the protein content. However, the T and S treatments significantly decreased the ascorbic acid content (p ≤ 0.05). Our results show that using the aqueous extract of tepals at 2 g/L and saffron at 1 g/L can improve the main secondary metabolites of fruits in greenhouse conditions.