Arrhenius plots of root respiration in some Arctic plants

The rate of root respiration as a function of temperature has been studied in four plant species growing in Svalbard. Ranunculus sulphureus has a relatively low respiration rate at low temperatures with a Q10of 2.6 similar to that of temperate plants. Carex misandra, Dupontia fisheri, and Eriophorum scheuchzeri, however, have relatively high rates of respiration at low temperatures with Q10values in the range 1.4 to 1.7. Monophasic Arrhenius plots were derived for all species and gave calculated apparent activation energies of 16 kcal mol-1for Ranunculus but values of 5 to 8 kcal mol-1for Carex, Dupontia, and Eriophorum. These latter three species possess lower apparent activation energies for respiration than are found in temperate plants and possible mechanisms which may be involved are discussed.