EFFECTS OF ELEVATED CO2 ON CELLULAR MECHANISMS, GROWTH AND DEVELOPMENT OF TREES WITH PARTICULAR REFERENCE TO HYBRID POPLAR

Growth is often stimulated when C-3 plants, including trees, are expos ed to elevated CO2, although evidence from the literature suggests tha t the responsiveness of trees to CO2 varies, depending on species. Thi s paper explores some of the cellular mechanisms which underlie increa sed growth, using both the authors' own data and information from the literature. Mechanisms include photosynthetic fixation of CO2 and the role of Rubisco, the link between carbon fixation and growth, in parti cular, how increased carbon is thought to influence the process of pla nt cell expansion and cell production and finally the consequences of cellular effects for the growth and development of whole planes. Data are presented for the growth and development of hybrid poplars in elev ated CO2, following both field (open-top chambers) and laboratory expe riments which suggest that this type of tree with indeterminate, rapid growth may be favoured by the CO2 concentrations of the next century.