Balancing photosynthetic light-harvesting and light-utilization capacities in potato leaf tissue during acclimation to different growth temperatures

We investigated the effect of temperature during growth and development on the relationship between light-harvesting capacity, indicated by chlorophyll concentration, and light-utilization potential, indicated by light- and bicarbonate-saturated photosynthetic oxygen evolution, in Solanum tuberosum L. cv. Norland. Conal plantles were transplanted and grown at 20°C for 2 weeks before transfer to 12, 16, 20, 24 and 28°C for 6 weeks. After 4 weeks of the temperature treatments, leaf tissue fresh weights per area were one-third higher in plants grown at 12°C vs those grown at 28°C. Conversely, chlorophyll content per area in tissue grown at 12°C was less than one-half of that of tissue grown at 28°C at 4 weeks. Photosynthetic capacity measured at a common temperature of 20°C and expressed on a chlorophyll basis was inversely proportional to growth temperature. Leaf tissue from plants grown at 12°C for 4 weeks had photosynthetic rates that were 3-fold higher on a chlorophyll basis than comparable tissue from plants grown at 28°C. These results suggest that the relationship between light-harvesting capacity and light-utilization potential varies 3-fold in response to the growth temperatures examined. The role of this response in avoidance of photoinhibition is discussed.