BAP (6-Benzylaminopurine) Seed-Priming Enhanced Growth, Antioxidant Accumulation and Anthocyanin Metabolism in Olive Sprouts

Abstract

Given the importance of olive sprouts, it is crucial to explore their potential as an innovative source of bioactive and nutritive compounds through research. Here, we aimed at investigating the potential role of benzylaminopurine (BAP) in improving the tissue chemical composition and bioactivity of olive sprouts. To this end, seeds of two olive varieties (Olea europaea L. vr. Kroniaki and Coratina) were primed with BAP at 25 µM. A substantial enhancement was observed in biomass accumulation by 35% and 30% in Kroniaki and Coratina varieties, respectively. Likewise, the photosynthetic pigments (total chlorophyll, α- and β-carotene, lutein and β-cryptoxanthin) in both varieties were increased, mainly in Coratina. At primary metabolic level, BAP priming improved sprout lipid composition, particularly in Coratina variety. At antioxidant level, BAP priming improved lipid antioxidants (α-, β- and γ-tocopherols) and water-soluble antioxidants (phenols, flavonoids, ascorbate, glutathione and anthocyanins) in both olive varieties. At the anthocyanins level, their precursors (phenylalanine, cinnamic acid, coumaric acid and naringenin) and key biosynthetic enzyme activity (phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), coenzyme A ligase (4CL) and cinnamate 4-hydroxylase (C4H)) were improved in olive varieties, but to a greater extent in Coratina variety. Overall, the sprouts of BAP-primed olive seeds could potentially enhance their nutritional value, suggesting that the sprouts of BAP-primed olive seeds can be used as a food ingredient and additives.