Metabolism of small carbon molecules in the cambium and developing xylem of Pinus strobus L

This thesis investigates the ability of the cambium and developing xylem of Pinus strobus L. to metabolise small carbon molecules. The molecules investigated include acetaldehyde, ethanol, formaldehyde, methanol and carbon dioxide. These molecules are involved in three distinct areas of plant metabolism, ethanol fermentation, one-carbon metabolism and dark fixation, none of which has been well investigated in cambium of any species. This thesis investigates the metabolism of these molecules and the relationship of their metabolism to phenology of cambial growth and development of new xylem.; High levels of ethanol and acetaldehyde were found in both cambial zone and developing xylem. The dormant cambium and developing xylem also showed evidence of anaerobic metabolism. Both showed a relationship with the phenology of secondary growth, with levels of ethanol being inversely related to cell division and levels of acetaldehyde being positively related to xylogenesis. Both cambial zone and developing xylem possessed the enzymes necessary for ethanol fermentation.; High levels of both methanol and formaldehyde were also found in cambial zone and developing xylem. Methanol content was inversely related to cell division activity and xylogenesis, while formaldehyde showed no relationship with phenology. Although methanol may be metabolized to formaldehyde, evidence was obtained that it is not the sole substrate for formaldehyde production. High activity of alcohol dehydrogenase for both acetaldehyde and formaldehyde substrates were found. A NADP+ specific isozyme of alcohol dehydrogenase active with ethanol was also found, evidently the first such report in biochemistry.; Carbon dioxide was readily metabolised by the cambium and developing xylem. Enzymes of carbon dioxide metabolism, phosphoenolpyruvate carboxylase, carbamoyl phosphate synthetase, acetyl CoA carboxylase and pyruvate carboxylase were found to be active in the cambium and developing xylem of eastern white pine. This is the first evidence for the activity of these enzymes in cambium and developing xylem.