Will the exceptional productivity of Miscanthus x giganteus increase further under rising atmospheric CO2?

Autor(es)

de Souza, Amanda P. ^[1] ; Arundale, Rebecca A. ^[2] ; Dohleman, Frank G. ^[2] ; Long, Stephen P. ^[2] ; Buckeridge, Marcos S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Bot, Lab Fisiol Ecol Plantas LAFIECO, Sao Paulo - Brazil

^[2] Univ Illinois, Inst Genom Biol, Urbana, IL 61801 - USA

• Tipo de documento: Artigo Científico
• Fonte: Agricultural and Forest Meteorology; v. 171, p. 82-92, APR 15 2013.
• Citações Web of Science: 29

Resumo

Miscanthus x giganteus is a highly productive perennial rhizomatous C-4 grass originating from Japan. It has been widely promoted as a bioenergy crop on account of its high productivity and low input requirements. Furthermore, such plantations are expected to last for decades, raising the question of how production, composition and therefore supply to the end-user facility may change with global atmospheric change. Atmospheric {[}CO2] is expected to rise from about 394 mu mol mol(-1) today to 550 mu mol mol(-1) by 2050. C-3 crops show large yield increases in response to rising {[}CO2] through increased photosynthesis, while experiments on C-4 plants differ in their findings. Effects of elevated {[}CO2] on photosynthesis and nonstructural carbohydrate (NSC) in M. x giganteus have not been reported. The SoyFACE facility provided a unique opportunity to test the hypothesis that elevated {[}CO2] under open-air conditions would alter the photosynthesis, productivity and composition of M. x giganteus in the field. The crop was planted in the spring of 2009 in 4 replicates of elevated (585 mu mol mol(-1)) and of ambient {[}CO2], and the plant material harvested following senescence in 2009 and 2010. Although significant increases in leaf CO2 uptake due to elevated {[}CO2] were observed during dry periods, there was no treatment effect on plant biomass. There was no significant treatment effect on leaf total NSC although they were higher on one occasion in the stems, primarily due to increased accumulation of hexoses. In both treatments, starch was the major stem NSC, whereas sucrose concentrations reached about 4-5% of total dry weight maturity, perhaps reflecting the close relationship of this plant with sugarcane. Starch content in roots and rhizomes increased along the season in both treatments, but was decreased in elevated {[}CO2], which might affect regrowth during subsequent seasons. (C) 2012 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 07/55457-4 - Mecanismos fotossintéticos e metabólicos relacionados às respostas da cana-de-açúcar cultivada em atmosfera enriquecida de CO2
• Beneficiário: Amanda Pereira de Souza
• Modalidade de apoio: Bolsas no Brasil - Doutorado