title: The effects of phenotypic plasticity on photosynthetic performance in winter rye, winter wheat and Brassica napus.
abstract: The contributions of phenotypic plasticity to photosynthetic performance in winter (cv Musketeer, cv Norstar) and spring (cv SR4A, cv Katepwa) rye (Secale cereale) and wheat (Triticum aestivum) cultivars grown at either 20°C [non-acclimated (NA)] or 5°C [cold acclimated (CA)] were assessed. The 22-40% increase in light-saturated rates of CO₂ assimilation in CA vs NA winter cereals were accounted for by phenotypic plasticity as indicated by the dwarf phenotype and increased specific leaf weight. However, phenotypic plasticity could not account for (1) the differential temperature sensitivity of CO₂ assimilation and photosynthetic electron transport, (2) the increased efficiency and light-saturated rates of photosynthetic electron transport or (3) the decreased light sensitivity of excitation pressure and non-photochemical quenching between NA and NA winter cultivars. Cold acclimation decreased photosynthetic performance of spring relative to winter cultivars. However, the differences in photosynthetic performances between CA winter and spring cultivars were dependent upon the basis on which photosynthetic performance was expressed. Overexpression of BNCBF17 in Brassica napus generally decreased the low temperature sensitivity (Q₁₀) of CO₂ assimilation and photosynthetic electron transport even though the latter had not been exposed to low temperature. Photosynthetic performance in wild type compared to the BNCBF17-overexpressing transgenic B. napus indicated that CBFs/DREBs regulate not only freezing tolerance but also govern plant architecture, leaf anatomy and photosynthetic performance. The apparent positive and negative effects of cold acclimation on photosynthetic performance are discussed in terms of the apparent costs and benefits of phenotypic plasticity, winter survival and reproductive fitness.
authors: Department of Biology and The Biotron Experimental Climate Change Research Centre, The University of Western Ontario, London, ON N6A 5B7, Canada.
authors: Keshav
authors: K
authors: Dahal
authors: Khalil
authors: K
authors: Kane
authors: Winona
authors: W
authors: Gadapati
authors: Elizabeth
authors: E
authors: Webb
authors: Leonid V
authors: LV
authors: Savitch
authors: Jasbir
authors: J
authors: Singh
authors: Pooja
authors: P
authors: Sharma
authors: Fathey
authors: F
authors: Sarhan
authors: Fred J
authors: FJ
authors: Longstaffe
authors: Bernard
authors: B
authors: Grodzinski
authors: Norman P A
authors: NP
authors: Hüner
mesh_terms: D000064:Acclimatization / Q000187:drug effects / Q000528:radiation effects; D018533:Biomass; D029688:Brassica napus / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology; D002247:Carbon Isotopes; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003080:Cold Temperature; D004579:Electron Transport / Q000187:drug effects / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D010455:Peptides / Q000378:metabolism; D010641:Phenotype; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects / Q000648:ultrastructure; D018526:Plant Transpiration / Q000187:drug effects / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D012434:Secale / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013696:Temperature; D014908:Triticum / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D014867:Water / Q000502:physiology
chemical_list: D002247:Carbon Isotopes; D010455:Peptides; D012333:RNA, Messenger; D014867:Water; D002734:Chlorophyll; D002245:Carbon Dioxide; D000077194:Chlorophyll A