The Influence of Growth Temperature and Growth Irradiance on Thermal Dissipation of Excess Excitation Energy in Winter Rye
A sustained depression in photosynthetic efficiency due to the absorption of excess light energy is referred to as photoinhibition of photosynthesis [1, 2]. Environmental stresses, such as low temperature, further limit the ability of the plant to utilize light energy and enhance the ohotoinhibitory response . However, photosynthetic organisms have evolved many mecha.lisms to cope with the absorption of excess light energy. Non-photochemical quenching (NPQ) of chlorophyll (Chl) a fluorescence refers to a combination of photoprotective mechanisms which dissipate excess excitation energy as heat in the light-harvesting complexes associated with photosystem II (PSII) [3–5]. The development of a frans-thylakoid ApH appears to be essential for the development of NPQ which is in some way enhanced by the xanthophyll cycle [3–5]. The extent of NPQ, in some cases, but not all, is strongly correlated to levels of antheraxanthin (A) and zeaxanthin (Z) formed from violaxanthin (V) via the xanthophyll cycle under high-light conditions [3–6].
Key wordslight acclimation non-photochemical quenching photochemical quenching photoinhibition temperature acclimation xanthophyll cycle
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