Elevated CO₂ atmosphere promotes plant growth and inulin production in the cerrado species Vernonia herbacea

• Published in: Functional plant biology : FPB Vol. 37; no. 3; pp. 223 - 231
• Main Authors: Oliveira, Vanessa F, Zaidan, Lilian B.P, Braga, Márcia R, Aidar, Marcos P.M, Carvalho, Maria Angela M
• Format: Journal Article
• Language: English
• Published: Collingwood, Victoria: CSIRO Publishing 2010
• Subjects: aerial parts; air pollution; beta-fructofuranosidase; biosynthesis; carbohydrate metabolism; carbon dioxide; climatic factors; dry matter accumulation; elevated atmospheric gases; enzyme activity; fructans; greenhouse gases; inulin; net assimilation rate; photosynthesis; plant growth; rhizophores; roots; Vernonia; Vernonia herbacea; Brazil
• ISSN: 1445-4408; 1445-4416
• DOI: 10.1071/FP09164

Carbon allocation in biomass is an important response of plants to the increasing atmospheric [CO₂]. The effects of elevated [CO₂] are scarcely reported in fructan-accumulating plants and even less in tropical wild species storing this type of carbohydrate. In the present study, the effects of high [CO₂] atmosphere was evaluated on growth, biomass allocation and fructan metabolism in Vernonia herbacea (Vell.) Rusby, an Asteraceae from the Brazilian cerrado, which accumulates inulin-type fructans in the underground organs (rhizophores). Plants were cultivated for 120 days in open-top chambers (OTCs) under ambient (~380μmolmol⁻¹), and elevated (~760μmolmol⁻¹) [CO₂]. Plant growth, photosynthesis, fructan contents, and the activities of fructan metabolising enzymes were analysed in the rhizophores at Time 0 and 15, 30, 60, 90 and 120 days. Plants under elevated [CO₂] presented increases in height (40%), photosynthesis (63%) and biomass of aerial (32%) and underground (47%) organs when compared with control plants. Under elevated [CO₂] plants also presented higher 1-SST, 1-FFT and invertase activities and lower 1-FEH activity. Although fructan concentration remained unchanged, fructan productivity was higher in plants maintained under elevated [CO₂], due to their higher rhizophore biomass. This is the first report on the effects of elevated [CO₂] on a plant species bearing underground organs that accumulate fructans. Our results indicate that plants of V. herbacea can benefit from elevated atmospheric [CO₂] by increasing growth and carbon allocation for the production of inulin, and may contribute to predict a future scenario for the impact of this atmospheric condition on the herbaceous vegetation of the cerrado.