title: Silicon nutrition increases grain yield, which, in turn, exerts a feed-forward stimulation of photosynthetic rates via enhanced mesophyll conductance and alters primary metabolism in rice.
abstract: Silicon (Si) is not considered to be an essential element for higher plants and is believed to have no effect on primary metabolism in unstressed plants. In rice (Oryza sativa), Si nutrition improves grain production; however, no attempt has been made to elucidate the physiological mechanisms underlying such responses. Here, we assessed crop yield and combined advanced gas exchange analysis with carbon isotope labelling and metabolic profiling to measure the effects of Si nutrition on rice photosynthesis, together with the associated metabolic changes, by comparing wild-type rice with the low-Si rice mutant lsi1 under unstressed conditions. Si improved the harvest index, paralleling an increase in nitrogen use efficiency. Higher crop yields associated with Si nutrition exerted a feed-forward effect on photosynthesis which was fundamentally associated with increased mesophyll conductance. By contrast, Si nutrition did not affect photosynthetic gas exchange during the vegetative growth phase or in de-grained plants. In addition, Si nutrition altered primary metabolism by stimulating amino acid remobilization. Our results indicate a stimulation of the source capacity, coupled with increased sink demand, in Si-treated plants; therefore, we identify Si nutrition as an important target in attempts to improve the agronomic yield of rice.
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Kelly C
authors.initials: KC
authors.lastname: Detmann
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Wagner L
authors.initials: WL
authors.lastname: Araújo
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Samuel C V
authors.initials: SCV
authors.lastname: Martins
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Lílian M V P
authors.initials: LMVP
authors.lastname: Sanglard
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Josimar V
authors.initials: JV
authors.lastname: Reis
authors.affiliation: Departamento de Zootecnia, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Edenio
authors.initials: E
authors.lastname: Detmann
authors.affiliation: Departamento de Fitopatologia, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Fabrício Á
authors.initials: FÁ
authors.lastname: Rodrigues
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Adriano
authors.initials: A
authors.lastname: Nunes-Nesi
authors.affiliation: Max-Planck-Institute of Molecular Plant Physiology, Am Muelenberg 1, 14476, Potsdam-Golm, Germany.
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil.
authors.forename: Fábio M
authors.initials: FM
authors.lastname: DaMatta
mesh_terms: D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism / Q000502:physiology; D018556:Crops, Agricultural / Q000378:metabolism / Q000502:physiology; D004579:Electron Transport; D007553:Isotope Labeling; D058503:Mesophyll Cells / Q000378:metabolism*; D055442:Metabolome; D009584:Nitrogen / Q000378:metabolism; D012275:Oryza / Q000378:metabolism* / Q000502:physiology; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology; D018526:Plant Transpiration; D012639:Seeds / Q000378:metabolism* / Q000502:physiology; D012825:Silicon / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen; D012825:Silicon