Effects of elevated temperature and elevated CO{sub 2} on foliar senescence of Acer seedlings
- St. Olaf College, Northfield, MN (United States)
An important response mechanism of trees to a warmer, CO{sub 2}-enriched atmosphere could be an alteration of phenological relationships. Autumn leaf senescence and abscission were tracked in sugar maple (Acer saccharum) and red maple (A. rubrum) seedlings growing in open-top chambers in ambient or elevated CO{sub 2} in combination with ambient or elevated temperature. Chlorophyll concentration was estimated weekly with a portable reflectance meter calibrated against conventional analysis of chlorophyll in leaf extracts. Abscission was quantified as the percentage of total plant leaf area that had abscised by certain dates. In both species chlorophyll loss from mid-October to mid-November was retarded in plants grown since May at a constant temperature offset 4{degrees}C higher than ambient. Likewise, leaf abscission began later and progressed more slowly in the warmer chambers. These plants still had 80% of their leaf area attached, and the leaves were still green, at the end of the growing season. Carbon dioxide concentration had little effect on leaf senescence or abscission. The results demonstrate the potential for climate warming to extend the growing season, which could enhance plant productivity. However, delayed senescence could also cause nutrient loss by disrupting retranslocation from leaves prior to the end of the growing season.
- OSTI ID:
- 95800
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:004728-0065
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 2; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
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