Elevated CO sub 2 does not delay leaf senescence in white oak or yellow-poplar seedlings in the field
- Oak Ridge National Laboratory, TN (USA)
- Kalamazoo College, MI (USA)
We hypothesized that the higher rates of photosynthesis in plants grown in elevated concentrations of atmospheric CO{sub 2} would delay the onset and progression of autumn leaf senescence. An effect of CO{sub 2} on leaf duration could be an important determinant of growth and could alter the processes of nutrient conservation and winter hardening. In May of 1989, white oak and yellow-poplar seedlings were planted in the ground in open-top chambers. The plants were exposed continuously to regulated CO{sub 2} concentrations (ambient, ambient+150 {mu}l{center dot}l{sup {minus}1}, and ambient+300 {mu}l{center dot}l{sup {minus}1}), with two chambers per treatment and up to 10 plants of each species per chamber. Photosynthesis and stem growth were measured throughout the growing season. Leaf senescence was monitored beginning in September by measuring pigment concentrations, salt-extractable protein concentrations, and free amino acids in upper leaves. Leaf area was measured as the leaves abscised. Photosynthesis remained significantly higher in the elevated CO{sub 2} concentrations throughout the growing season. Stem growth was enhanced in the ambient+300 treatment (both species) and ambient+150 treatment (white oak) relative to plants in ambient CO{sub 2}. Chlorophyll concentrations decreased with increasing CO{sub 2} concentration, but CO{sub 2} had no effect on the timing of chlorophyll loss, and there was no other evidence of an effect of CO{sub 2} concentration on leaf senescence. In both species the time required for 50% of total leaf area to abscise varied by less than 2 days between treatments. The conclusion that CO{sub 2} concentration does not affect leaf senescence under field conditions contrasts with the results from some growth chamber studies.
- OSTI ID:
- 5858411
- Report Number(s):
- CONF-9007196-; CODEN: PPYSA
- Journal Information:
- Plant Physiology, Supplement; (USA), Vol. 93:1; Conference: Annual meeting of the American Society of Plant Physiologists, Indianapolis, IN (USA), 29 Jul - 2 Aug 1990; ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of elevated temperature and elevated CO{sub 2} on foliar senescence of Acer seedlings
Acclimation of respiratory O{sub 2} uptake in green tissues of field-grown native species after long-term exposure to elevated atmospheric CO{sub 2}
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CARBON DIOXIDE
BIOLOGICAL EFFECTS
LEAVES
OAKS
PHOTOSYNTHESIS
POPLARS
SEEDLINGS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
SYNTHESIS
TREES
540110*
550200 - Biochemistry