The objective of this study was to determine the effects of long-term exposure to elevated CO<SUB>2</SUB> on the growth and morphology of seedlings of Sitka spruce and silver birch, with a focus on the effects of elevated CO<SUB>2</SUB> on the expansion, surface characteristics, specific leaf area, anatomy and chlorophyll content of leaves of silver birch. Seedlings of Sitka spruce and silver birch were placed in pots in open top chambers receiving ambient or elevated CO<SUB>2</SUB>. After one growing season there was a significant increase in biomass production in seedlings of Sitka spruce grown in elevated CO<SUB>2</SUB> compared to those grown in ambient CO<SUB>2</SUB>, but after eighteen months this effect had disappeared. The initial increase in biomass was a result of a significant increase in root mass. At the end of the second growing season there was no effect of elevated CO<SUB>2</SUB> on allocation of dry mass. There was no effect of elevated CO<SUB>2</SUB> on total number of branches produced at the end of the second growing season but there was an increase in the rate of branch production. Nitrogen, phosphorus and potassium concentration of leaves was reduced in plants grown in elevated CO<SUB>2</SUB>. After one growing season biomass was increased in elevated CO<SUB>2</SUB> plants by <I>ca</I> 20%, rates of photosynthesis were also higher in elevated CO<SUB>2</SUB> plants. There was no effect of CO<SUB>2</SUB> treatment on root: shoot ratio. There was a significant increase in branch production in plants grown in elevated CO<SUB>2</SUB>, but despite an increase in leaf area production early on in the growing season, there was no difference in total tree leaf area at the end of the growing season. Nitrogen, phosphorus and potassium concentration of leaves was reduced in plants grown in elevated CO<SUB>2</SUB> and leaves on elevated CO<SUB>2</SUB> plants senesced <I>ca</I> one week earlier than leaves of plants grown in ambient CO<SUB>2</SUB>.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:650053 |
| Date | January 1994 |
| Creators | Evans, Lynn Patricia |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14808 |
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