Low temperature and low irradiation induced irreversible damage of strawberry seedlings

摘要

Low temperature (LT) and low irradiation (LI) are common factors posing a great risk to plants. The study aimed to elucidate the effects of LT and LI and recovery on the photosynthetic apparatus, photoinhibition of PSII, and reactive oxygen metabolism of strawberry seedlings. The results showed that strawberry growth slowed down or even stopped and total chlorophyll content, stomatal conductance, net photosynthetic rate, and maximal quantum yield of PSII photochemistry decreased, while intercellular CO 2 concentration increased under LI, LT, and combined stress (LL). Additionally, JIP-test showed that compared to LI or LT stress, LL-stressed plants had lower quantum yields and efficiencies and functional antenna size, and higher reaction center activity. Besides, the contents of hydrogen peroxide and malondialdehyde increased, while the activity of superoxide dismutase, peroxidase, and catalase were significantly inhibited compared with the control. After the stress was relieved, the photosynthesis of LL-stressed plants recovered poorly.