title: Adaxial/abaxial specification in the regulation of photosynthesis and stomatal opening with respect to light orientation and growth with CO2 enrichment in the C4 species Paspalum dilatatum.
abstract: Whole-plant morphology, leaf structure and composition were studied together with the effects of light orientation on the dorso-ventral regulation of photosynthesis and stomatal conductance in Paspalum dilatatum cv. Raki plants grown for 6 wk at either 350 or 700 microl l(-1) CO(2). Plant biomass was doubled as a result of growth at high CO(2) and the shoot:root ratio was decreased. Stomatal density was increased in the leaves of the high CO(2)-grown plants, which had greater numbers of smaller stomata and more epidermal cells on the abaxial surface. An asymmetric surface-specific regulation of photosynthesis and stomatal conductance was observed with respect to light orientation. This was not caused by dorso-ventral variations in leaf structure, the distribution of phosphoenolpyruvate carboxylase (PEPC) and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) proteins or light absorptance, transmittance or reflectance. Adaxial/abaxial specification in the regulation of photosynthesis results from differential sensitivity of stomatal opening to light orientation and fixed gradients of enzyme activation across the leaf.
authors.affiliation: Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.|Centro de Engenharia Biológica & Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749-016 Lisboa, Portugal.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Soares
authors.affiliation: Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Driscoll
authors.affiliation: CEBAS-CSIC, Department of Plant Physiology, PO Box 164, 30080-Murcia, Campus de Espinardo, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Olmos
authors.affiliation: Wageningen University, Department of Plant Sciences, Horticultural Production Chains Group, Marijkeweg 22, 6709 PG Wageningen, the Netherlands.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Harbinson
authors.affiliation: Centro de Engenharia Biológica & Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749-016 Lisboa, Portugal.
authors.forename: Maria Celeste
authors.initials: MC
authors.lastname: Arrabaça
authors.affiliation: Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.|Present address: School of Agriculture, Food and Rural Development, Agriculture Building, The University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK.
authors.forename: Christine H
authors.initials: CH
authors.lastname: Foyer
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008027:Light; D031781:Paspalum / Q000254:growth & development / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000254:growth & development* / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D002245:Carbon Dioxide