Drought-induced chilling tolerance in cucumber involves an increase in photosynthesis by alleviated photoinhibition

We assessed changes in gas exchange parameters, chlorophyll fluorescence parameters, and pigment content for cucumber (Cucumis sativus L.) seedlings subjected to low temperature stress (day/night temperature of 8/5°C) that had been either pre-treated with 10% polyethylene glycol (PEG) for 2 d or not.
The results revealed that seedlings pre-treated with PEG to simulate drought showed a decrease in chilling injury index values compared with the non-treated (control) seedlings.
Low temperature stress decreased the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), actual photochemical efficiency of PSII (Φ_PSII), maximal photochemical efficiency of PSII in darkness (F_v/F_m), maximal photochemical efficiency of PSII in light (F_v‘/F_m‘), and the photochemical quenching coefficient (qP), whereas increased intercellular CO₂ concentration (Ci), initial fluorescence (F₀), and non-photochemical quenching coefficient (NPQ). PEG pre-treatment diminished the decrease levels in Pn, Gs, Tr, F_v/F_m, Φ_PSII, F_v‘/F_m‘ and qP, and the increase levels in Ci, F₀ and NPQ of cucumber seedlings caused by chilling stress.
Furthermore, PEG pre-treatment also increased the chlorophyll and carotenoids contents in the chilling-stressed seedlings.
These results suggest that PEG pre-treatment alleviates photoinhibition and stimulates the adaptation of cucumber to chilling stress.

XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): International Symposium on Innovation and New Technologies in Protected Cropping

Huangai Bi, Xubing Dong, Guoxiu Wu, Qingming Li, Xizhen Ai

chilling tolerance, drought-stress induction, photoinhibition, cucumber

https://doi.org/10.17660/ActaHortic.2015.1107.31