Growth and carbon allocation of tropical and temperate N-fixing trees grown in elevated CO{sub 2}
- Duke Univ., Durham, NC (United States)
Seeds of two tree species, Gliricidia seplum (tropical) and Robinia pseudoacacia (temperate), were inoculated with N-fixing Rhizobium bacteria and grown in environmentally controlled glasshouses for 75 days to determine the effects of atmospheric CO{sub 2} on seedling growth and carbon allocation. Seedlings were grown in ambient CO{sub 2}(35 Pa) and elevated CO{sub 22}(70 Pa) and watered with a N-deficient nutrient solution such that bacterial N-fixation was the only source of N. Elevated CO{sub 2} increased leaf, stem, root and total biomass in Gliricidia, but did not affect nodule mass; Robinia biomass was unchanged by CO{sub 2}. Leaf photosynthetic rates at 70 Pa CO{sub 2} were increased 49% in Gliricidia, but were unchanged in Robinia, and there was no change in respiration rate in either species. A {sup 14}CO{sub 2} labelling experiment demonstrated that elevated CO{sub 2} did not affect the kinetics or allocation patterns of photosynthetically fixed carbon to nodules or other plant parts in either species. Our results demonstrate that Gliricidia, but not Robinia, will show an early, positive growth and photosynthetic response to elevated CO{sub 2} in N-poor soils, suggesting that tropical N-fixing trees may be more responsive than temperate N-fixing trees to future atmospheric CO{sub 2} conditions.
- OSTI ID:
- 107143
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:006512-0059
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 3; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
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