Ability to acclimate photochemical processes by saplings of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) growing in contrasting light environments was investigated using chlorophyll a fluorescence. The leaves of saplings acclimated to irradiance under the open canopy of Larix decidua Mill. showed higher photosynthetic efficiency and more efficient photoprotective mechanism than those under the shade of the denser Picea abies Karst. canopy. Interspecific differences in quantum yield of PS II photochemistry, apparent electron transport rate, non-photochemical quenching and the values of the cardinal points of light response curves of these parameters resulted from the shade adaptation of leaves and leaf lifespan. Acclimation to shade did not increase sensitivity to strong PS II downregulation induced by light patch of low intensity but predisposed both species to photoinhibition caused by high light stress. They were able to efficiently use light patches of low intensity, but after high light stress beech leaves from the Larix stand recovered more dynamically in quantum yield of PS II photochemistry than silver fir. It may give an advantage to beech in between-species competition for use of short-lasting and intensive sun patches.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.