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.
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.
Soares
Ana Sofia
AS
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.
Driscoll
Simon P
SP
Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
Olmos
Enrique
E
CEBAS-CSIC, Department of Plant Physiology, PO Box 164, 30080-Murcia, Campus de Espinardo, Spain.
Harbinson
Jeremy
J
Wageningen University, Department of Plant Sciences, Horticultural Production Chains Group, Marijkeweg 22, 6709 PG Wageningen, the Netherlands.
Arrabaça
Maria Celeste
MC
Centro de Engenharia Biológica & Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749-016 Lisboa, Portugal.
Foyer
Christine H
CH
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.
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
D010940:Plant Proteins; D002245:Carbon Dioxide