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Title: Effects of CO[sub 2] on apparent dark respiration in loblolly and ponderosa pine seedlings grown in sub-optimal, optimal or supra-optimal nitrogen

Conference · · Bulletin of the Ecological Society of America; (United States)
OSTI ID:7016050
;  [1];  [2]
  1. Duke Univ., Durham, NC (United States)
  2. Oregon State Univ., Corvallis, OR (United States)

Differences in the response of apparent dark respiration to elevated CO[sub 2] and nitrogen were studied in loblolly (Pinus taeda) and ponderosa (P. ponderosa) pine seedlings. Seedlings of both species were grown for 160 days in two CO[sub 2] partial pressures (35 or 70 Pa) and three levels of soil nitrogen (1, 3.5 or 7 mM NH[sub 4]) in sterilized sand culture. Ponderosa pine had higher apparent respiration rates (CO[sub 2] efflux in the dark) than loblolly pine across all CO[sub 2] and nitrogen treatments. Loblolly poine grown in elevated CO[sub 2] had lower apparent respiration rates than seedlings grown in low CO[sub 2]. Apparent respiration for ponderosa pine was similar at both CO[sub 2] partial pressures. Apparent respiration increased with nitrogen in both species. The direct effects of ambient CO[sub 2] environment surrounding isolated leaves or whole seedlings. Short term increases in CO[sub 2] partial pressures consistently resulted in significant decreases in CO[sub 2] efflux across the growth treatments and measurement scales. Leaf level decreases in CO[sub 2] efflux were as large as 90% when CO[sub 2] partial pressures were increased form 0 to 100 Pa Species level differences in apparent respiration, and its response to nitrogen availability, may influence the potential of these two species to grow and sequester carbon as atmospheric CO[sub 2] increases.

OSTI ID:
7016050
Report Number(s):
CONF-940894-; CODEN: BECLAG
Journal Information:
Bulletin of the Ecological Society of America; (United States), Vol. 75:2; Conference: Annual Ecological Society of America (ESA) meeting: science and public policy, Knoxville, TN (United States), 7-11 Aug 1994; ISSN 0012-9623
Country of Publication:
United States
Language:
English