UV-screening and springtime recovery of photosynthetic capacity in leaves of Vaccinium vitis-idaea above and below the snow pack

• Published in: Plant Physiology and Biochemistry
• Main Authors: Solanki, Twinkle, Aphalo, Pedro, Neimane, Santa, Hartikainen, Saara, Pieristè, Marta, Shapiguzov, Alexey, Porcar-Castell, Albert, Atherton, Jon, Heikkilä, Anu, Robson, Thomas Matthew
• Other Authors: Helsingin yliopisto = Helsingfors universitet = University of Helsinki, University of Latvia (LU), Étude et compréhension de la biodiversité (ECODIV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Multiscale Material Science for Energy and Environment (MSE 2), Massachusetts Institute of Technology (MIT)-Centre National de la Recherche Scientifique (CNRS), Department of Forest Sciences Helsinki, Faculty of Agriculture and Forestry Helsinki, Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Finnish Meteorological Institute (FMI), Academy of Finland 304519, Finnish National Agency for Education (EDUFI fellowship program), Tiina and Antti Herlin Foundation 20180642
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: Anthocyanins; Arctic browning; Flavonoids; Photoprotection; Spectral quality; Understorey; spring dehardening; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; Arctic; Browning
• Online Access: https://hal.science/hal-02183530; https://doi.org/10.1016/j.plaphy.2018.09.003

International audience Evergreen plants in boreal biomes undergo seasonal hardening and dehardening adjusting their photosynthetic capacity and photoprotection; acclimating to seasonal changes in temperature and irradiance. Leaf epidermal ultraviolet (UV)-screening by flavonols responds to solar radiation, perceived in part through increased ultraviolet-B (UV-B) radiation, and is a candidate trait to provide cross-photoprotection. At Hyytiälä Forestry Station, central Finland, we examined whether the accumulation of flavonols was higher in leaves of Vaccinium vitis-idaea L. growing above the snowpack compared with those below the snowpack. We found that leaves exposed to colder temperatures and higher solar radiation towards the top of hummocks suffered greater photoinhibition than those at the base of hummocks. Epidermal UV-screening was highest in upper-hummock leaves, particularly during winter when lower leaves were beneath the snowpack. There was also a negative relationship between indices of flavonols and anthocyanins across all leaves suggesting fine-tuning of flavonoid composition for screening vs. antioxidant activity in response to temperature and irradiance. However, the positive correlation between the maximum quantum yield of photosystem II photochemistry (Fv/Fm) and flavonol accumulation in upper hummock leaves during dehardening did not confer on them any greater cross-protection than would be expected from the general relationship of Fv/Fm with temperature and irradiance (throughout the hummocks). Irrespective of timing of snow-melt, photosynthesis fully recovered in all leaves, suggesting that V. vitis-idaea has the potential to exploit the continuing trend for longer growing seasons in central Finland without incurring significant impairment from reduced duration of snow cover.