title: Elevated CO2 increases photosynthesis, biomass and productivity, and modifies gene expression in sugarcane.
abstract: Because of the economical relevance of sugarcane and its high potential as a source of biofuel, it is important to understand how this crop will respond to the foreseen increase in atmospheric [CO(2)]. The effects of increased [CO(2)] on photosynthesis, development and carbohydrate metabolism were studied in sugarcane (Saccharum ssp.). Plants were grown at ambient (approximately 370 ppm) and elevated (approximately 720 ppm) [CO(2)] during 50 weeks in open-top chambers. The plants grown under elevated CO(2) showed, at the end of such period, an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient [CO(2)]. These plants also had lower stomatal conductance and transpiration rates (-37 and -32%, respectively), and higher water-use efficiency (c.a. 62%). cDNA microarray analyses revealed a differential expression of 35 genes on the leaves (14 repressed and 22 induced) by elevated CO(2). The latter are mainly related to photosynthesis and development. Industrial productivity analysis showed an increase of about 29% in sucrose content. These data suggest that sugarcane crops increase productivity in higher [CO(2)], and that this might be related, as previously observed for maize and sorghum, to transient drought stress.
authors.affiliation: Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Amanda Pereira
authors.initials: AP
authors.lastname: De Souza
authors.forename: Marilia
authors.initials: M
authors.lastname: Gaspar
authors.forename: Emerson Alves
authors.initials: EA
authors.lastname: Da Silva
authors.forename: Eugênio César
authors.initials: EC
authors.lastname: Ulian
authors.forename: Alessandro Jaquiel
authors.initials: AJ
authors.lastname: Waclawovsky
authors.forename: Milton Yutaka
authors.initials: MY
authors.lastname: Nishiyama
authors.forename: Renato Vicentini
authors.initials: RV
authors.lastname: Dos Santos
authors.forename: Marcelo Menossi
authors.initials: MM
authors.lastname: Teixeira
authors.forename: Glaucia Mendes
authors.initials: GM
authors.lastname: Souza
authors.forename: Marcos Silveira
authors.initials: MS
authors.lastname: Buckeridge
mesh_terms: D018533:Biomass; D002245:Carbon Dioxide / Q000494:pharmacology*; D002482:Cellulose / Q000378:metabolism; D005740:Gases / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D006813:Humidity; D008027:Light; D008031:Lignin / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects* / Q000528:radiation effects; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D054046:Plant Stomata / Q000187:drug effects / Q000528:radiation effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D031786:Saccharum / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000528:radiation effects; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
chemical_list: D005740:Gases; C036909:lignocellulose; D002245:Carbon Dioxide; D013395:Sucrose; D002482:Cellulose; D008031:Lignin