Title The effect of long-term exposure of **Lolium perenne** L. plants to elevated $CO_{2}$ and/or elevated air temperature on quantum yield of photosystem 2 and net photosynthesis The effect of long-term exposure of **Lolium perenne** L. plants to elevated $CO_{2}$ and/or elevated air temperature on quantum yield of photosystem 2 and net photosynthesis Author Barták, M. Nijs, I. Impens, I. Faculty/Department Faculty of Sciences. Biology Publication type article Publication 1996 Praha , 1996 Subject Biology Source (journal) Photosynthetica. - Praha Volume/pages 32(1996) :4 , p. 549-562 ISSN 0300-3604 ISI A1996VM34000008 Carrier E Target language English (eng) Affiliation University of Antwerp Abstract The effects of long-term exposure of Lolium perenne L. plants to CO2 concentration elevated to 700 mu mol (CO2) mol(-1) (EC) and air temperature elevated by 4 degrees C (ET) on the quantum yield of electron transport of photosystem 2, PS2 (phi(2)) and on the potential yield of photochemical reactions of PS2 (F-v/F-m) measured by the chlorophyll (Chl) fluorescence method, were studied. The plants were exposed for 6 months in opened field greenhouses to four treatments simulating global atmospheric changes: (1) ambient CO2 (AC) and ambient air temperature, AT (ACAT - control), (2) EC and AT (ECAT), (3) AC and ET (ACET), and (4) EC and ET (ECET). When the plants were exposed to stepwise increased irradiance, a decrease in phi(2) was found under both AC and EC measuring concentrations. At high irradiances a significantly higher yield of PS2 was detected when measured under EC compared to AC regardless of long-term CO2 and temperature treatment (i.e., positive short-term. effect of EC). The short-term effect of EC on phi(2) as related to net photosynthetic rate (P-N) Shift was detected from irradiance response curves. At high irradiances and AC, phi(2) was reduced in comparison to control for the plants of EC and ET treatments (i.e., negative long-term effect of treatment). The long-term effect of both EC and ET on the yield of PS2 was attributed to a down-regulation of P-N caused by the treatment. The phi(2) was related to the actual rate of photosynthesis and the relationship between phi(2) and phi(CO2) was linear over a wide range of irradiances. No effect of long-term treatments on the dark-adapted F-v/F-m ratio was found in plants cultivated under natural greenhouse irradiance. E-info http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1996VM34000008&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1996VM34000008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1996VM34000008&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle