Ecophysiological roles of abaxial anthocyanins in a perennial understorey herb from temperate deciduous forests.
Accumulation of abaxial anthocyanins is an intriguing leaf trait particularly common among deeply shaded understorey plants of tropical and temperate forests whose ecological significance is still not properly understood. To shed light on it, possible ecophysiological roles of abaxial anthocyanins were tested in the perennial understorey herb of temperate deciduous forests Saxifraga hirsuta, chosen as a model species due to the coexistence of green and anthocyanic leaves and the presence of an easily removable lower anthocyanic epidermis. Anthocyanins accumulated during autumn, which temporally matched the overstorey leaf fall. Patterns of development of abaxial anthocyanins and direct measurements of photochemical efficiency under monochromatic light were not consistent with a photoprotective hypothesis. Enhancement of light capture also seemed unlikely since the back-scattering of red light towards the lower mesophyll was negligible. Seed germination was similar under acyanic and anthocyanic leaves. A relevant consequence of abaxial anthocyanins was the dramatic reduction of light transmission through the leaf. The dark environment generated underneath the Saxifraga canopy was enhanced by the horizontal repositioning of leaves, which occurs in parallel with reddening. This might play a role in biotic interactions by inhibiting vital processes of competitors, which may be of especial importance in spring before the overstorey leaves sprout.
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain Present address: Institute of Botany and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Sterwartestraße 15, A-6020 Innsbruck, Austria beatriz.fernandezm@ehu.es.
Beatriz
B
Fernández-Marín
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain IdAB-CSIC-UPNA-Government of Navarre, E-31192 Pamplona, Spain.
Raquel
R
Esteban
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain.
Fátima
F
Míguez
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain.
Unai
U
Artetxe
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain UPNA, E-31192 Pamplona, Spain.
Verónica
V
Castañeda
Department of Plant Biology, University of Barcelona. Av. Diagonal 643, E-08028 Barcelona, Spain.
Marta
M
Pintó-Marijuan
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain.
José María
JM
Becerril
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain.
José Ignacio
JI
García-Plazaola
Abaxial anthocyanins; Saxifraga hirsuta; lactucaxanthin; photoprotection; spectrum; winter