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Positive Effects of Elevated CO2 on an Important Brazilian Shrub

Paper Reviewed
Mendes de Sa, C.E., Negreiros, D., Fernandes, G.W., Dias, M.C. and Franco, A.C. 2014. Carbon dioxide-enriched atmosphere enhances biomass accumulation and meristem production in the pioneer shrub Baccharis dracunculifolia (Asteraceae). Acta Botanica Brasillica 28: 646-650.

In a study of Baccharis dracunculifolia -- a key pioneer Neotropical shrub and medicinal plant found in Brazil that is prized for its anti-ulcer and anti-inflammatory properties -- Mendes de Sa et al. (2014) grew specimens from seed in pots filled with a 2:3 mix of sand and vermiculite in open-top chambers maintained in a greenhouse at atmospheric CO2 concentrations of either 360 or 720 ppm, where they were periodically watered and fertilized over a period of 120 days, after which they were harvested and assessed for a number of different plant properties. And what did they thereby learn?

The five Brazilian researchers report that "seedlings grown under elevated CO2 showed higher values of total dry mass (increase of 134%), root dry mass (increase of 208%), stem dry mass (increase of 152%), leaf dry mass (increase of 97%), total leaf area (increase of 49%), plant height (increase of 52%), number of leaves (increase of 63%), number of branches (increase of 137%), number of nodes (increase of 34%) and length of internodes (increase of 17%) than plants grown in ambient [CO2]."

Not bad results for a plant that occurs, in the words of the five researchers, "in degraded areas and in early succession stages, in the transition zone between forest and grasslands," as reported by Muller et al. (2007) and Negreiros et al. (2014), as well as in "environments with low nutrient limitation."

Muller, S.C., Overbeck, G.E., Pfadenhauer, J. and Pillar, V.D. 2007. Plant functional types of woody species related to fire disturbance in forest-grassland ecotones. Plant Ecology 189: 1-14.

Negreiros, D., Esteves, D., Fernandes, G.W., Berbara, R.L.L., Oki, Y., Voichiato, M. and Chalub, C. 2014. Growth-survival tradeoff in the widespread tropical shrub Baccharis dracunculifolia (Asteraceae) in response to a nutrient gradient. Tropical Ecology 55: 167-176.

Posted 15 May 2015