caa a22 4500 445889748 CHVBK 20180317145612.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s11120-011-9621-9 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9621-9 The interrelationship between the lower oxygen limit, chlorophyll fluorescence and the xanthophyll cycle in plants [Elektronische Daten] [A. Wright, John DeLong, Arunika Gunawardena, Robert Prange] The lower oxygen limit (LOL) in plants may be identified through the measure of respiratory gases [i.e. the anaerobic compensation point (ACP) or the respiratory quotient breakpoint (RQB)], but recent work shows it may also be identified by a sudden rise in dark minimum fluorescence (F o). The interrelationship between aerobic respiration and fermentative metabolism, which occur in the mitochondria and cytosol, respectively, and fluorescence, which emanates from the chloroplasts, is not well documented in the literature. Using spinach (Spinacia oleracea), this study showed that Fo and photochemical quenching (q P) remained relatively unchanged until O2 levels dropped below the LOL. An over-reduction of the plastoquinone (PQ) pool is believed to increase F o under dark+anoxic conditions. It is proposed that excess cytosolic reductant due to inhibition of the mitochondria's cytochrome oxidase under low-O2, may be the primary reductant source. The maximum fluorescence (F m) is largely unaffected by low-O2 in the dark, but was severely quenched, mirroring changes to the xanthophyll de-epoxidation state (DEPS), under even low-intensity light (≈4μmolm−2s−1). In low light, the low-O2-induced increase in F o was also quenched, likely by non-photochemical and photochemical means. The degree of quenching in the light was negatively correlated with the level of ethanol fermentation in the dark. A discussion detailing the possible roles of cyclic electron flow, the xanthophyll cycle, chlororespiration and a pathway we termed ‘chlorofermentation' were used to interpret fluorescence phenomena of both spinach and apple (Malus domestica) over a range of atmospheric conditions under both dark and low-light. Her Majesty the Queen in Right of Canada, 2011 Chlorofermentation nationallicence Chlororespiration nationallicence Fermentation nationallicence Non-photochemical quenching nationallicence Photochemical quenching nationallicence Xanthophyll cycle nationallicence Wright A. Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut DeLong John Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut Gunawardena Arunika Department of Biology, Dalhousie University, B3H 4J1, Halifax, NS, Canada aut Prange Robert Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut Photosynthesis Research Springer Netherlands 107/3(2011-03-01), 223-235 0166-8595 107:3<223 2011 107 11120 https://doi.org/10.1007/s11120-011-9621-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9621-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wright A. Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut NATIONALLICENCE 700 1- DeLong John Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut NATIONALLICENCE 700 1- Gunawardena Arunika Department of Biology, Dalhousie University, B3H 4J1, Halifax, NS, Canada aut NATIONALLICENCE 700 1- Prange Robert Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, 32 Main Street, B4N 1J5, Kentville, NS, Canada aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 107/3(2011-03-01), 223-235 0166-8595 107:3<223 2011 107 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer