title: Influence of light and nitrogen on the photosynthetic efficiency in the C4plant Miscanthus × giganteus.
abstract: There are numerous studies describing how growth conditions influence the efficiency of C4photosynthesis. However, it remains unclear how changes in the biochemical capacity versus leaf anatomy drives this acclimation. Therefore, the aim of this study was to determine how growth light and nitrogen availability influence leaf anatomy, biochemistry and the efficiency of the CO2concentrating mechanism in Miscanthus × giganteus. There was an increase in the mesophyll cell wall surface area but not cell well thickness in the high-light (HL) compared to the low-light (LL) grown plants suggesting a higher mesophyll conductance in the HL plants, which also had greater photosynthetic capacity. Additionally, the HL plants had greater surface area and thickness of bundle-sheath cell walls compared to LL plants, suggesting limited differences in bundle-sheath CO2conductance because the increased area was offset by thicker cell walls. The gas exchange estimates of phosphoenolpyruvate carboxylase (PEPc) activity were significantly less than the in vitro PEPc activity, suggesting limited substrate availability in the leaf due to low mesophyll CO2conductance. Finally, leakiness was similar across all growth conditions and generally did not change under the different measurement light conditions. However, differences in the stable isotope composition of leaf material did not correlate with leakiness indicating that dry matter isotope measurements are not a good proxy for leakiness. Taken together, these data suggest that the CO2concentrating mechanism in Miscanthus is robust under low-light and limited nitrogen growth conditions, and that the observed changes in leaf anatomy and biochemistry likely help to maintain this efficiency.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.|School of Biological Science, Washington State University, Pullman, WA, 99163, USA.
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Ma
authors.affiliation: School of Biological Science, Washington State University, Pullman, WA, 99163, USA.|Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, 130024, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Nuria K
authors.initials: NK
authors.lastname: Koteyeva
authors.affiliation: Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Elena
authors.initials: E
authors.lastname: Voznesenskaya
authors.affiliation: School of Biological Science, Washington State University, Pullman, WA, 99163, USA.
authors.forename: Samantha S
authors.initials: SS
authors.lastname: Stutz
authors.affiliation: School of Biological Science, Washington State University, Pullman, WA, 99163, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Gandin
authors.affiliation: Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
authors.forename: Andreia M
authors.initials: AM
authors.lastname: Smith-Moritz
authors.affiliation: Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.|ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Heazlewood
authors.affiliation: School of Biological Science, Washington State University, Pullman, WA, 99163, USA. acousin@wsu.edu.
authors.forename: Asaph B
authors.initials: AB
authors.lastname: Cousins
mesh_terms: D008027:Light; D009584:Nitrogen; D010788:Photosynthesis; D006109:Poaceae / Q000502:physiology*
chemical_list: D009584:Nitrogen
keywords: C4 photosynthesis; Carbon isotope discrimination; Light; Miscanthus; Nitrogen