The Carbon Economy of Rubus chamaemorus L. I. Photosynthesis

Studies on the photosynthetic activity of Rubus chamaemorus L. in controlled environment conditions are reported. These show that material collected from Moor House National Nature Reserve, England has a photosynthetic light saturation point of 100 J m−2s−1 (380–720 nm) and a temperature optimum for photosynthesis between 10 and 15 °C. A marked decline in net CO2 uptake is evident at temperatures in excess of 18 ° C; this persists for some time after return to an optimum temperature regime. Leaves show rapid responses to changes in both light intensity and temperature, and show no evidence of an endogenous rhythm in photosynthetic rate.