Multidimensional evaluation of PEG-induced osmotic stress responses in strawberry cultivars

OpenAlex · English

Water-deficit stress is a major abiotic factor limiting strawberry productivity. Three cultivars (Kara, Fronteras, and Osmanli) were subjected to in vitro polyethylene glycol (PEG 6000)-induced osmotic stress (2%, 4%) to evaluate physiological, biochemical, and antioxidative responses. Photosystem II (PSII) photochemical efficiency, chlorophyll content (SPAD), leaf temperature, proline and phenolic contents, and activities of peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO) were determined. PEG-induced osmotic stress significantly influenced several physiological and biochemical traits in a genotype-dependent manner. Kara maintained higher PSII efficiency, chlorophyll content, relative water content, and biomass, indicating greater physiological stability under PEG-induced osmotic stress. Fronteras exhibited elevated POD and PPO activities, indicating stronger induction of enzymatic stress responses under PEG-induced osmotic stress, while Osmanli primarily exhibited osmotic adjustment and stress-associated physiological responses. Multivariate analyses revealed two predominant response patterns: maintenance of water status and photosynthetic performance under moderate stress, and increased osmolyte accumulation and enzymatic defence under higher PEG-induced osmotic stress. These findings indicate stress-intensity-dependent shifts from physiological maintenance toward biochemical defence responses and identify physiological and biochemical traits that may assist in screening strawberry cultivars under PEG-induced osmotic stress.