Increased susceptibility to photoinhibition in pre‐existing needles experiencing low temperature at spring budbreak in Sakhalin spruce ( Picea glehnii) seedlings

• Published in: Physiologia Plantarum
• Main Authors: Kitao, Mitsutoshi, Qu, Laiye, Koike, Takayoshi, Tobita, Hiroyuki, Maruyama, Yutaka
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2004
• Subjects: Sakhalin
• Online Access: http://dx.doi.org/10.1111/j.1399-3054.2004.00393.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1399-3054.2004.00393.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1399-3054.2004.00393.x

The seasonal changes in photosynthetic properties in 1‐year‐old needles of Sakhalin spruce ( Picea glehnii ) were measured using the chlorophyll fluorescence technique at various temperatures (5, 10, 20, 25 and 30°C). In the course of seasonal change, a temporary decrease in the quantum yield of PSII electron transport (Φ PSII ) was observed just before budbreak. A decline in photochemical quenching ( q P ) was observed at the same time as that of Φ PSII but only at the two lowest temperatures (5 and 10°C). Photochemical efficiency of open PSII ( F v ′/ F m ′) also declined just before budbreak at 25 and 30°C. An increase in thermal energy dissipation as indicated by a decrease in F v ′/ F m ′ before budbreak was not significant at lower temperatures (5 and 10°C) in spite of the declines in q P . This implies that thermal energy dissipation necessitated by the decline in Φ PSII might not be sufficiently strong to prevent a decline in q P at lower temperatures. On the other hand, at higher temperatures no decline was observed in q P because Φ PSII decreased to a relatively small extent, therefore thermal energy dissipation is sufficient in coping with the excessive energy accumulation in PSII. Seedlings of Sakhalin spruce exposed to ambient air temperature below 10°C before budbreak exhibited photoinhibition indicated by a decrease in the maximal photochemical efficiency of PSII ( F v / F m ) after an overnight dark adaptation. The present study suggests that 1‐year‐old shoots of Sakhalin spruce have an increased susceptibility to photoinhibition at low temperature just before budbreak.