Norway spruce; non-radiative dissipation; xanthophyll cycle; light acclimation; non-photochemical quenching

For conifers the enhanced efficiency of non-radiative energy dissipation (NRD) within PS II is supposed to represent a key process of acclimation to elevated irradiance under both laboratory and field conditions. The needles of Norway spruce acclimated to high irradiance exhibit considerable acceleration of NRD induction and significantly greater efficiency of violaxanthin de-epoxidation (approximately 90%) than is usual for other plant species with corresponding xanthophyll cycle pool size and LHC II size (Chl a/b ratio). Nevertheless, knowledge of dynamics of these processes is insufficient. Therefore we focused on the relation between kinetics of NRD induction and de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin during acclimation of Norway spruce to high irradiance.

For conifers the enhanced efficiency of non-radiative energy dissipation (NRD) within PS II is supposed to represent a key process of acclimation to elevated irradiance under both laboratory and field conditions. The needles of Norway spruce acclimated to high irradiance exhibit considerable acceleration of NRD induction and significantly greater efficiency of violaxanthin de-epoxidation (approximately 90%) than is usual for other plant species with corresponding xanthophyll cycle pool size and LHC II size (Chl a/b ratio). Nevertheless, knowledge of dynamics of these processes is insufficient. Therefore we focused on the relation between kinetics of NRD induction and de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin during acclimation of Norway spruce to high irradiance.