Pushan Bag

Keywords conifers photosystems nonphotochemical quenching (NPQ) direct energy transfer alternative electron transport flavodiiron proteins Conifers retain chlorophyll in winter even when they cannot photosynthesise In nature, plants often face environmental fluctuations ranging from seconds (cloud covering) to months (seasonal changes) [1–3]. These environmental fluctuations, if ignored, can downregulate or damage photosynthesis and compromise plant growth.

1 INTRODUCTION Chlorophyll (Chl) fluorescence, the light emitted from the key pigments of the photosynthetic apparatus has - since the first study of the phenomenon (Kautsky and Hirsch, 1931) - provided over the last few decades fundamental insights into the functioning of the photosynthetic apparatus of green organisms (Kalaji et al., 2014, Kalaji et al., 2017).