The Carbon Economy of Rubus chamaemorus L. II. Respiration

Respiratory activity and seasonal changes in carbohydrate content of the storage organs of Rubus chamaemorus L. have been investigated. Leaf dark respiration rate increases in a non-linear manner from 0·7 mg CO2 evolved dm−2 h−1 at 0 °C to 4·6 rng CO2 evolved dm−2 hh−1 at 30 °C. Root and rhizome respiration rates increase from 1 μ1 O2 uptake g−1 fresh weight h−1 at 0.7 ° C to 10 μ10, uptake g−1 f. wt h−1 at 20 °C. Rhizome carbohydrate reserves decline from a September peak of 33 per cent alcohol insoluble d. wt to 16 per cent in May. The circumpolar distribution of R. chamaemorus is discussed in relation to the evidence presented here and in the preceding paper of the series.