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Elevated CO2 Increases Seedling Biomass within Three Days of Emergence
Reference
Tischler, C.R., Polley, H.W., Johnson, H.B. and Pennington, R.E.  2000.  Seedling response to elevated CO2 in five epigeal species.  International Journal of Plant Science 161: 779-783.

What was done
Seedlings were grown from germination in glasshouses receiving atmospheric CO2 concentrations of 365 and 700 ppm to determine if rapid responses to elevated CO2 are possible in seedlings of bagpod sesbania (Sesbania vesicaria), cotton (Gossypium hirsutum), mesquite (Prosopis glandulosa), cucumber (Cucumis sativus) and hemp sesbania (Sesbania exaltata).

What was learned
Elevated CO2 significantly increased total biomass in all five species by 11 to 36% within three days of emergence.  This early stimulation in total biomass then increased to 56 to 82% within 16 days after emergence for all species.  In addition, it was noted that these early increases in biomass were not correlated with seed size or relative growth rate at ambient CO2 concentration, indicating that neither of these two parameters can readily predict species responses to atmospheric CO2 enrichment.

What it means
As the atmospheric CO2 concentration continues to rise, it is likely that seedlings of these five species will respond rapidly and robustly to this impetus for growth by exhibiting increases in biomass.  In addition, data from this study suggest that it is difficult to project species responses to atmospheric CO2 enrichment by using seed weight or relative growth rate as a predictive indicator.


Reviewed 13 December 2000