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Titolo:
Effects of daylength and temperature on the growth and photosynthesis of an Arctic cyanobacterium, Schizothrix calcicola (Oscillatoriaceae)
Autore:
Tang, EPY; Vincent, WF;
Indirizzi:
Univ Laval, Dept Biol, St Foy, PQ G1K 7P4, Canada Univ Laval St Foy PQ Canada G1K 7P4 Dept Biol, St Foy, PQ G1K 7P4, Canada Univ Laval, Ctr Etud Nord, St Foy, PQ G1K 7P4, Canada Univ Laval St Foy PQ Canada G1K 7P4 Etud Nord, St Foy, PQ G1K 7P4, Canada
Titolo Testata:
EUROPEAN JOURNAL OF PHYCOLOGY
fascicolo: 3, volume: 35, anno: 2000,
pagine: 263 - 272
SICI:
0967-0262(200008)35:3<263:EODATO>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIATOM SKELETONEMA-COSTATUM; GYRODINIUM-AUREOLUM HULBURT; TOTAL CARBON METABOLISMS; MARINE DIATOM; LIGHT-INTENSITY; CHEMICAL-COMPOSITION; PHOTOSYSTEM-II; GREEN-ALGAE; IRRADIANCE; PHYTOPLANKTON;
Keywords:
Arctic; Antarctic; cyanobacteria; growth; photoperiod; photosynthesis; pigments; polar; respiration; temperature;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Tang, EPY Univ Laval, Dept Biol, St Foy, PQ G1K 7P4, Canada Univ Laval StFoy PQ Canada G1K 7P4 St Foy, PQ G1K 7P4, Canada
Citazione:
E.P.Y. Tang e W.F. Vincent, "Effects of daylength and temperature on the growth and photosynthesis of an Arctic cyanobacterium, Schizothrix calcicola (Oscillatoriaceae)", EUR J PHYC, 35(3), 2000, pp. 263-272

Abstract

Cyanobacteria are often the dominant phototrophs in high-latitude lakes and streams where they must experience continuously low temperature and extreme variations in daylength. The present study examined the interaction between these two variables for the growth and physiology of an Arctic isolate of the mat-forming species Schizothrix calcicola (Agardh) Gomont. Growth rates (mu), photosynthesis (P), respiration (R), pigment composition and in vivo absorption characteristics were measured under 15 combinations of daylengths (8:16, 12:12, 16:8, 20:4 and 24:0 L/D) and temperatures (5, 15 and 25degreesC). mu increased with increasing temperature (mu (max) at 5 degreesC = 0.12 d(-1), mu (max) at 25 degreesC = 0.28 d(-1)) and a similar trend was observed in photosynthetic capacity (average P-max(B) at 5 degreesC = 4.42 mg C (mg Chl a)(-1) h(-1), average P-max(B) at 25 degreesC = 5.74 mg C (mg Chl a)(-1) h(-1)), pigment content and absorbance. Daylength had a positive effect on mu and pigment absorption, but not pigment content. The shapeof the mu -daylength curve varied with temperature: mu was a linear function of daylength at 5 degreesC, but at 15 and 25 degreesC the relationship resembled a rectangular hyperbola and mu saturated at 16:8 and 12:12 L/D, respectively. The non-linear relationship between mu and daylength at high temperature was related to a reduction in net photosynthesis under extended daylength; at 25 degreesC, net P under 24:0 L/D was 0.82+/-0.37 mg O-2 (mg Chl a)(-1) h(-1), while under 8:16 L/D, it was 6.54+/-0.69 mg O-2 (mg Chl n)(-1) h(-1). The constant increase in growth with increasing daylength at low temperature may reflect an adaptive tolerance to the combination of cold temperature and continuous daylight during the Arctic summer.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 10:39:48