title: Low-temperature leaf photosynthesis of a Miscanthus germplasm collection correlates positively to shoot growth rate and specific leaf area.
abstract: The C4 perennial grass miscanthus has been found to be less sensitive to cold than most other C4 species, but still emerges later in spring than C3 species. Genotypic differences in miscanthus were investigated to identify genotypes with a high cold tolerance at low temperatures and quick recovery upon rising temperatures to enable them to exploit the early growing season in maritime cold climates. Suitable methods for field screening of cold tolerance in miscanthus were also identified.
  
  
  
  Fourteen genotypes of M. sacchariflorus, M. sinensis, M. tinctorius and M. × giganteus were selected and grown under warm (24 °C) and cold (14 °C) conditions in a controlled environment. Dark-adapted chlorophyll fluorescence, specific leaf area (SLA) and net photosynthetic rate at a photosynthetically active radiation (PAR) of 1000 μmol m(-2) s(-1) (A1000) were measured. Photosynthetic light and CO2 response curves were obtained from 11 of the genotypes, and shoot growth rate was measured under field conditions.
  
  
  
  A positive linear relationship was found between SLA and light-saturated photosynthesis (Asat) across genotypes, and also between shoot growth rate under cool field conditions and A1000 at 14 °C in a climate chamber. When lowering the temperature from 24 to 14 °C, one M. sacchariflorus exhibited significantly higher Asat and maximum photosynthetic rate in the CO2 response curve (Vmax) than other genotypes at 14 °C, except M × giganteus 'Hornum'. Several genotypes returned to their pre-chilling A1000 values when the temperature was increased to 24 °C after 24 d growth at 14 °C.
  
  
  
  One M. sacchariflorus genotype had similar or higher photosynthetic capacity than M × giganteus, and may be used for cultivation together with M × giganteus or for breeding new interspecies hybrids with improved traits for temperate climates. Two easily measured variables, SLA and shoot growth rate, may be useful for genotype screening of productivity and cold tolerance.
authors.affiliation: Aarhus University, Department of Agroecology, Blichers Allé 20, DK-8830 Tjele, Denmark, xiurong.jiao@agro.au.dk.
authors.forename: Xiurong
authors.initials: X
authors.lastname: Jiao
authors.affiliation: Aarhus University, Department of Agroecology, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Kørup
authors.affiliation: Aarhus University, Department of Agroecology, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Mathias Neumann
authors.initials: MN
authors.lastname: Andersen
authors.affiliation: Aarhus University, Department of Food Science, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark.
authors.forename: Karen Koefoed
authors.initials: KK
authors.lastname: Petersen
authors.affiliation: Swedish University of Agricultural Sciences, Department of Biosystems and Technology, SE-230 53 Alnarp, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Prade
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland and.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Jeżowski
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland and.
authors.forename: Szymon
authors.initials: S
authors.lastname: Ornatowski
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland and.
authors.forename: Barbara
authors.initials: B
authors.lastname: Górynowicz
authors.affiliation: University of Illinois, Institute of Genomic Biology, 1206 W. Gregory Dr. 138 IGB, Urbana, IL 61801, USA.
authors.forename: Idan
authors.initials: I
authors.lastname: Spitz
authors.affiliation: Aarhus University, Department of Agroecology, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Lærke
authors.affiliation: Aarhus University, Department of Agroecology, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Uffe
authors.initials: U
authors.lastname: Jørgensen
mesh_terms: D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D005838:Genotype; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology*; D018520:Plant Shoots / Q000254:growth & development / Q000502:physiology; D011003:Ploidies; D006109:Poaceae / Q000235:genetics / Q000502:physiology*; D013696:Temperature
chemical_list: D002734:Chlorophyll
keywords: C4 photosynthesis; Cold tolerance; M. sacchariflorus; M. sinensis; M. tinctorius; M. × giganteus; dark-adapted chlorophyll fluorescence; genotypic difference; light and CO2 response curves