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Density‐dependent responses of reproductive allocation to elevated atmospheric CO 2 in Phytolacca americana
Author(s) -
He J.S.,
Bazzaz F. A.
Publication year - 2003
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00660.x
Subject(s) - reproduction , biology , population density , biomass (ecology) , population , photosynthesis , botany , zoology , density dependence , ecology , horticulture , demography , sociology
Summary• This study was conducted to determine whether elevated CO 2alters patterns of plant reproduction, and whether density affects population‐ and individual‐level responses to elevated CO2 . • Phytolacca americanawas grown in a glasshouse at three population densities under ambient and elevated CO2 environments, and harvested at both vegetative and seed mature stages. • CO 2 did not affect the observed or estimated minimum size required for reproduction. At the population‐level, elevated CO 2 increased the total and above‐ground biomass at both harvests. Density decreased both measurements at the second harvest. At the individual‐level, elevated CO 2 increased reproductive mass but decreased seed size, and the responses of reproductive allocation were density‐dependent. Net photosynthesis at saturating light (P max ) increased under elevated CO 2 , but decreased with density, with a CO 2 × density interaction. • hese results indicate that CO 2advances 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 CO2inP. americana .