Effects of High-Temperature Stress on Photosynthetic Characteristics and Antioxidant Enzyme System of Paeonia ostii

Paeonia ostii is an economically important oil crop, which has been widely cultivated in the middle and lower reaches of Yangtze River China recent years. Although P. highly adaptable to environment, prolonged high summer temperature this region severely inhibits its growth, adversely affects seed yield quality. In study, plants were subjected 20°C/15°C (day/night) 40°C/35°C temperatures for 15 days. The changes physiological biochemical indicators under high-temperature stress initially investigated. results showed that with deepening leaf etiolation, chlorophyll a b concentration, carotenoid Soil Plant Analysis Development (SPAD) values relative water content decreased significantly, while both electrical conductivity (REC) free proline concentration upward trend. Meanwhile, continuous accumulation reactive oxygen species (ROS) plants, led increased activity antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) ascorbate (APX). Moreover, extension treatment, anatomical structures destroyed, resulting photochemical efficiency photosystem II (PSII) reaction center photosynthesis was inhibited. Taken together, these provide reference understanding response establish foundation further research on relevant underlying molecular mechanisms.