CO[sub 2] exchange and growth of the Crassulacean acid metabolism plant opuntia ficus-indica under elevated CO[sub 2] in open-top chambers
- Univ. of California, Los Angeles, CA (United States)
CO[sub 2] uptake, water vapor conductance, and biomass production of Opuntia ficus-indica, a Crassulacean acid metabolism species, were studied at CO[sub 2] concentrations of 370, 520, and 720 [mu]L L[sup [minus]1] in open-top chambers during a 23-week period. Nine weeks after planting, daily net CO[sub 2] uptake for basal cladodes at 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2] was 76 and 98% higher, respectively, than at 370 [mu]L L[sup [minus]1]. Eight weeks after daughter cladodes emerged, their daily net CO[sub 2] uptake was 35 and 49% higher at 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2], respectively, than at 370 L L[sup [minus]1]. Daily water-use efficiency was 88% higher under elevated CO[sub 2] for basal cladodes and 57% higher for daughter cladodes. The daily net CO[sub 2] uptake capacity for basal cladodes increased for 4 weeks after planting and then remained fairly constant, whereas for daughter cladodes, it increased with cladode age, became maximal at 8 to 14 weeks, and then declined. The percentage enhancement in daily net CO[sub 2] uptake caused by elevated CO[sub 2] was greatest initially for basal cladodes and at 8 to 14 weeks for daughter cladodes. The chlorophyll content per unit fresh weight of chlorenchyma for daughter cladodes at 8 weeks was 19 and 62% lower in 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2], respectively, compared with 370 [mu]L L[sup [minus]1]. Despite the reduced chlorophyll content, plant biomass production during 23 weeks in 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2] was 21 and 55% higher, respectively, than at 370 [mu]L L[sup [minus]1]. The root dry weight nearly tripled as the CO[sub 2] concentration was doubled, causing the root/shoot ratio to increase with CO[sub 2] concentration. During the 23-week period, elevated CO[sub 2] significantly increased CO[sub 2] uptake and biomass production of O. 35 refs., 4 figs., 1 tab.
- DOE Contract Number:
- FG03-91ER61252; FC03-87ER60615
- OSTI ID:
- 5692211
- Journal Information:
- Plant Physiology; (United States), Vol. 103:2; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CACTI
PLANT GROWTH
CARBON DIOXIDE
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
UPTAKE
BIOMASS
CHLOROPHYLL
METABOLISM
WATER USE
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
ENERGY SOURCES
GROWTH
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PROTEINS
RENEWABLE ENERGY SOURCES
560300* - Chemicals Metabolism & Toxicology