Authors: Hendrik Poorter Marta PérezSoba
Publish Date: 2001/09/01
Volume: 129, Issue: 1, Pages: 1-20
Abstract
Under benign environmental conditions plant growth is generally stimulated by elevated atmospheric CO2 concentrations When environmental conditions become sub or supraoptimal for growth changes in the biomass enhancement ratio BER total plant biomass at elevated CO2 divided by plant biomass at the current CO2 level may occur We analysed literature sources that studied CO2×environment interactions on the growth of herbaceous species and tree seedlings during the vegetative phase For each experiment we calculated the difference in BER for plants that were grown under optimal and nonoptimal conditions Assuming that interactions would be most apparent if the environmental stress strongly diminished growth we scaled the difference in the BER values by the growth reduction due to the stress factor In our compilation we found a large variability in CO2×environment interactions between experiments To test the impact of experimental design we simulated a range of analyses with a planttoplant variation in size common in experimental plant populations in combination with a number of replicates generally used in CO2×environment studies A similar variation in results was found as in the compilation of real experiments showing the strong impact of stochasticity We therefore caution against strong inferences derived from single experiments and suggest rather a reliance on average interactions across a range of experiments Averaged over the literature data available low soil nutrient supply or suboptimal temperatures were found to reduce the proportional growth stimulation of elevated CO2 In contrast BER increased when plants were grown at low water supply albeit relatively modestly Reduced irradiance or high salinity caused BER to increase in some cases and decrease in others resulting in an average interaction with elevated CO2 that was not significant Under high ozone concentrations the relative growth enhancement by elevated CO2 was strongly increased to the extent that high CO2 even compensated in an absolute way for the harmful effect of ozone on growth No systematic difference in response was found between herbaceous and woody species for any of the environmental variables considered
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