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Titolo:
Photosynthetic pathway variation in leafy members of two subfamilies of the Cactaceae
Autore:
Martin, CE; Wallace, RS;
Indirizzi:
Univ Kansas, Dept Bot, Lawrence, KS 66045 USA Univ Kansas Lawrence KS USA66045 ansas, Dept Bot, Lawrence, KS 66045 USA Iowa State Univ, Dept Bot, Ames, IA 50011 USA Iowa State Univ Ames IA USA50011 tate Univ, Dept Bot, Ames, IA 50011 USA
Titolo Testata:
INTERNATIONAL JOURNAL OF PLANT SCIENCES
fascicolo: 4, volume: 161, anno: 2000,
pagine: 639 - 650
SICI:
1058-5893(200007)161:4<639:PPVILM>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
CRASSULACEAN ACID METABOLISM; WATER-USE EFFICIENCY; GAS-EXCHANGE; PEPEROMIA PIPERACEAE; CO2 UPTAKE; CAM; EVOLUTIONARY; ACCUMULATION; SUCCULENTS; FIXATION;
Keywords:
C-3 photosynthesis; Cactaceae; CAM; evolution; gas exchange; leaves; stems;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Martin, CE Univ Kansas, Dept Bot, Lawrence, KS 66045 USA Univ Kansas Lawrence KS USA 66045 Bot, Lawrence, KS 66045 USA
Citazione:
C.E. Martin e R.S. Wallace, "Photosynthetic pathway variation in leafy members of two subfamilies of the Cactaceae", INT J PL SC, 161(4), 2000, pp. 639-650

Abstract

Patterns of 24-h CO2 exchange and diel fluctuations in tissue acid concentrations were measured in leafy and leafless shoots of 10 species in the Pereskioideae and eight species in the Opuntioideae (Cactaceae). The species were selected to represent a range of phylogenetic histories. Leafy shoots of all species in the Pereskioideae exhibited C-3 patterns of gas exchange, and net CO2 exchange of leafless stems in all but one species was negative during the day and night. Although nighttime CO2 uptake was not observed inshoots or stems of any of the pereskioid taxa, tissue acidity increased atnight to a small degree in leaves of six species and stems of five species, indicative of low levels of CAM-cycling. In contrast, in leafy shoots of nearly all species in the Opuntioideae, CO2 uptake occurred during the day and the night. Gas-exchange rates were typically greater during the day. Asis typical of CAM, nighttime maximal water use efficiency often greatly exceeded daytime values. Tissue malic acid concentrations increased overnightin leaves and stems of all eight opuntioid species. Examination of the data from a phylogenetic perspective illustrates evidence of low levels of CAMscattered among the primarily C-3 members of the more ancestral Pereskioideae. Furthermore, such consideration of the taxa in the more derived Opuntioideae (comparing the genera from most ancestral to most derived, that is, Austrocylindropuntia --> Quiabentia --> Pereskiopsis --> Cylindropuntia) revealed that CAM became increasingly less important in the leaves of the various taxa, whereas this water-conservative pathway of photosynthesis becameincreasingly more important in the stems. The results of this study indicate that members of the Pereskioideae should be restricted to moister habitats or must restrict the timing of growth to wet seasons, whereas the observed combinations of the C-3 and CAM pathways in the opuntioid taxa should prove beneficial in conserving water in the sporadically arid tropical and subtropical habitats of these plants.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 13:38:51