Density-dependent responses of reproductive allocation to elevated atmospheric CO2 in Phytolacca americana
Article first published online: 24 JAN 2003
Volume 157, Issue 2, pages 229–239, February 2003
How to Cite
He, J.-S. and Bazzaz, F. A. (2003), Density-dependent responses of reproductive allocation to elevated atmospheric CO2 in Phytolacca americana. New Phytologist, 157: 229–239. doi: 10.1046/j.1469-8137.2003.00660.x
- Issue published online: 24 JAN 2003
- Article first published online: 24 JAN 2003
- Received: 5 June 2002 Accepted: 28 October 2002
- Phytolacca americana;
- reproductive allocation;
- minimum size for flowering;
- density dependence;
- elevated CO2
- •This study was conducted to determine whether elevated CO 2 alters patterns of plant reproduction, and whether density affects population- and individual-level responses to elevated CO 2 .
- •Phytolacca americana was grown in a glasshouse at three population densities under ambient and elevated CO 2 environments, and harvested at both vegetative and seed mature stages.
- •CO2 did not affect the observed or estimated minimum size required for reproduction. At the population-level, elevated CO2 increased the total and above-ground biomass at both harvests. Density decreased both measurements at the second harvest. At the individual-level, elevated CO2 increased reproductive mass but decreased seed size, and the responses of reproductive allocation were density-dependent. Net photosynthesis at saturating light (Pmax) increased under elevated CO2, but decreased with density, with a CO2 × density interaction.
- •hese results indicate that CO 2 advances timing of flowering by changing growth rate rather than modifying minimum size required for reproduction, while density modifies the responses of reproductive allocations to elevated CO 2 in P. americana .