caa a22 4500 445890266 CHVBK 20180317145614.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-011-9672-y doi (NATIONALLICENCE)springer-10.1007/s11120-011-9672-y The effects of moderately high temperature on zeaxanthin accumulation and decay [Elektronische Daten] [Ru Zhang, David Kramer, Jeffrey Cruz, Kimberly Struck, Thomas Sharkey] Moderately high temperature reduces photosynthetic capacities of leaves with large effects on thylakoid reactions of photosynthesis, including xanthophyll conversion in the lipid phase of the thylakoid membrane. In previous studies, we have found that leaf temperature of 40°C increased zeaxanthin accumulation in dark-adapted, intact tobacco leaves following a brief illumination, but did not change the amount of zeaxanthin in light-adatped leaves. To investigate heat effects on zeaxanthin accumulation and decay, zeaxanthin level was monitored optically in dark-adapted, intact tobacco and Arabidopsis thaliana leaves at either 23 or 40°C under 45-min illumination. Heated leaves had more zeaxanthin following 3-min light but had less or comparable amounts of zeaxanthin by the end of 45min of illumination. Zeaxanthin accumulated faster at light initiation and decayed faster upon darkening in leaves at 40°C than leaves at 23°C, indicating that heat increased the activities of both violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZE). In addition, our optical measurement demonstrated in vivo that weak light enhances zeaxanthin decay relative to darkness in intact leaves of tobacco and Arabidopsis, confirming previous observations in isolated spinach chloroplasts. However, the maximum rate of decay is similar for weak light and darkness, and we used the maximum rate of decay following darkness as a measure of the rate of ZE during steady-state light. A simulation indicated that high temperature should cause a large shift in the pH dependence of the amount of zeaxanthin in leaves because of differential effects on VDE and ZE. This allows for the reduction in ΔpH caused by heat to be offset by increased VDE activity relative to ZE. Springer Science+Business Media B.V., 2011 Zeaxanthin nationallicence Violaxanthin de-epoxidase nationallicence Zeaxanthin epoxidase nationallicence Moderately high temperature nationallicence ΔpH nationallicence Zhang Ru Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, 94305, Stanford, CA, USA aut Kramer David Plant Research Laboratory, Michigan State University, 48824, East Lansing, MI, USA aut Cruz Jeffrey Plant Research Laboratory, Michigan State University, 48824, East Lansing, MI, USA aut Struck Kimberly Department of Botany, University of Wisconsin, 53706, Madison, WI, USA aut Sharkey Thomas Department of Biochemistry and Molecular Biology, Michigan State University, 410 Biochemistry Building, 48824-1319, East Lansing, MI, USA aut Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 171-181 0166-8595 108:2-3<171 2011 108 11120 https://doi.org/10.1007/s11120-011-9672-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9672-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Ru Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, 94305, Stanford, CA, USA aut NATIONALLICENCE 700 1- Kramer David Plant Research Laboratory, Michigan State University, 48824, East Lansing, MI, USA aut NATIONALLICENCE 700 1- Cruz Jeffrey Plant Research Laboratory, Michigan State University, 48824, East Lansing, MI, USA aut NATIONALLICENCE 700 1- Struck Kimberly Department of Botany, University of Wisconsin, 53706, Madison, WI, USA aut NATIONALLICENCE 700 1- Sharkey Thomas Department of Biochemistry and Molecular Biology, Michigan State University, 410 Biochemistry Building, 48824-1319, East Lansing, MI, USA aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 171-181 0166-8595 108:2-3<171 2011 108 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer