Elevated Co₂ Influences Physiological Responses and Assimilatory Functions on Clones of Eucalyptus camaldulensis

Response of selected clones of Eucalyptus (Eucalyptuscamaldulensis Dehnh.) was measured to elevated CO₂ concentrations over a period of six months. Plants were exposed to double the atmospheric CO₂ concentrations in open top chambers. Responses measured included changes in concentrations of carbohydrate, chlorophyll, total protein in addition to net photosynthetic rate and growth over a period of six months. The study revealed CO₂-induced increases and differences in the response of different clones of E. camaldulensis. The results showed that elevated CO₂ had a significant influence on all the biochemical parameters. A significant increase was observed in total biomass of the plants, though only shoot development was enhanced significantly as a result of elevated CO₂. Root biomass was not affected by enhancement of CO₂. At the same time, internal CO₂ levels and stomatal conductance significantly varied, suggesting that intercellular CO₂ concentration might be an important determinant of photosynthetic acclimation in this species. Among the four productive clones released for commercial use by IFGTB, clone EC 1 was found most resilient to elevated CO₂ and temperature levels suggesting it's suitability for planting in anticipation of future oncreased in atmospheric CO₂ levels.