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CO2 Enrichment of Mungbean at Different Growth Stages
Das, M., Zaidi, P.H., Pal, M. and Sengupta, U.K.  2002.  Stage sensitivity of mungbean (Vigna radiata L. Wilczek) to an elevated level of carbon dioxide.  Journal of Agronomy and Crop Science 188: 219-224.

What was done
The authors grew tropical nitrogen-fixing mungbean plants (Vigna radiata L. Wilczek) in open-top chambers receiving atmospheric CO2 concentrations of 350 and 600 ppm for two growing seasons.  For the CO2-enriched plants, atmospheric CO2 enrichment was provided from either 0-20 or 21-40 days post-germination to study the effects of elevated CO2 at different growth stages.

What was learned
Elevated CO2 had a greater impact on mungbean productivity in the earlier, rather than the later, growth stage.  Leaf number, for example, was increased in CO2-enriched plants by 29 and 16% at 10 and 20 days post-germination, respectively, while it remained unaffected at 21 to 40 days post-germination.  In addition, elevated CO2 enhanced net rates of photosynthesis by approximately 40 and 16% at 0-20 days post-germination and 21-40 days post-germination, respectively.  Moreover, elevated CO2 decreased rates of respiration by 54 to 62%, with the greater declines occurring 0-20 days post-germination.

What it means
As the atmospheric CO2 concentration increases, it is likely that mungbean plants will exhibit enhanced rates of photosynthesis and decreased rates of respiration.  Together, these phenomenon should allow this species to produce greater amounts of biomass and yield.  In addition, if this species is grown in controlled environments, a limited exposure to elevated atmospheric CO2 concentrations for two to three weeks post-germination would likely lead to significant stimulations in growth and yield.

Reviewed 9 October 2002