| Abstract: | The rate of photorespiration in several grass species was shownto be highly variable and dependent on the species, genotype,and conditions under which the plants were grown. Photorespiration,measured as oxygen uptake, was negligible in Cenchrus ciliarisand Paspalum dilatatum but significant in Lolium spp. and Festucaarundinacea. There were significant differences in the rateof photorespiration among plants within a Lolium populationof diverse origin and these differences were independent ofthe conditions under which the plants were grown. Among thetemperate grasses there was a significant correlation betweenphotorespiration and the CO2-compensation concentration andboth parameters were very low in P. dilatatum. Plants grownin day/night temperatures of 15/10 °C compared with 25/20°C had faster rates of dark respiration but slower ratesof light respiration when measured at the same temperature.Photorespiration was faster than dark respiration although differencesin respiration among plants in the light were not shown in thedark. |
