Variation in acclimation of photosynthesis in Trifolium repens after eight years of exposure to free air CO2 enrichment (FACE). Journal of Experimental Botany 54 (393), 2769–2774. personal copy J.N.T. Darbah et al

The initial stimulation of photosynthesis observed on elevation of [CO2] in grasslands has been predicted to be a transient phenomenon constrained by the loss of photosynthetic capacity due to other limita-tions, notably nutrients and sinks for carbohydrates. Legumes might be expected partially to escape these feedbacks through symbiotic N2 ®xation. The Free-Air Carbon dioxide Enrichment (FACE) experiment at Eschikon, Switzerland, has been the longest running investigation of the effects of open-air elevation of [CO2] on vegetation. The prediction of a long-term loss of photosynthetic capacity was tested by ana-lysing photosynthesis in Trifolium repens L. (cv. Milkanova) in the spring and autumn of the eighth