Photosynthesis and growth of two rain forest species in simulated gaps under elevated CO{sub 2}

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Ecology

DOI:https://doi.org/10.1890/0012-9658(1997)078[0385:PAGOTR]2.0.CO;2· OSTI ID:478384

Roden, J S; Wiggins, D J; Ball, M C ^[1]

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1. Australian National Univ., Canberra (Australia)

Two species common to the temperate rain forests of New South Wales, Australia (Doryphora sassafras and Acmena smithii) were grown for 2 wk in either ambient (350 {mu}L/L) or elevated (700 {mu}L/L) CO{sub 2} concentrations and low light (30 {mu}mol photons{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}) after which the seedlings were exposed for over 9 wk to a midday 2-h highlight period (1250 {mu}mol photons{center_dot}m{sup {minus}2}{center_dot}s{sup {minus}1}, maximum) to simulate a tree fall gap. For both species, plants grown in elevated CO{sub 2} had greater biomass than plants grown in ambient CO{sub 2}. However, relative increases in biomass were greater in Acmena, an early-successional species, than Doryphora, a late-successional species. Recovery in quantum efficiencies over time was observed for Doryphora, implying physiological acclimation to the new light environment. Doryphora plants grown in elevated CO{sub 2} had lower values of F{sub v}/F{sub m} than plants grown in ambient CO{sub 2}. Although exposure to the simulated tree fall gap dramatically increased the conversion of pigments of the xanthophyll cycle, as well as increased the total pool size of xanthophyll cycle pigments relative to total chlorophyll concentration, there were no differences in either parameter between co{sub 2} treatments. Leaves of Doryphora and those seedlings grown in elevated CO{sub 2} had greater starch concentrations than Acmena and those seedlings grown in elevated CO{sub 2} had greater starch concentrations than Acmena and those seedlings grown in ambient CO{sub 2}, respectively. The reduction in quantum efficiencies for plants grown in elevated CO{sub 2} and exposed to a simulated tree fall gap is discussed in the context of the importance of gap phase regeneration for species in rain forest ecosystems and the potential effects of global change on those processes. 37 refs., 4 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 478384
• Journal Information: Ecology, Journal Name: Ecology Journal Issue: 2 Vol. 78; ISSN 0012-9658; ISSN ECOLAR
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL EFFECTS
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
FORESTS
PHOTOSYNTHESIS
PLANT GROWTH
PLANTS
TROPICAL REGIONS