scholarly journals C3 Photosynthesis and Crassulacean Acid Metabolism in a Kansas Rock Outcrop Succulent, Talinum calycinum Engelm. (Portulacaceae)

1983 ◽  
Vol 73 (3) ◽  
pp. 718-723 ◽  
Author(s):  
Craig E. Martin ◽  
Aaron Klaas Zee
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Rock Outcrop ◽  
C3 Photosynthesis

scholarly journals Phosphoenolpyruvate carboxylase from pennywort (Umbilicus rupestris). Changes in properties after exposure to water stress

1984 ◽  
Vol 218 (2) ◽  
pp. 387-393 ◽  
Author(s):  
P P Daniel ◽  
J A Bryant ◽  
F I Woodward
Keyword(s):  
Water Stress ◽  
Phosphoenolpyruvate Carboxylase ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Marked Decrease ◽  
Cam Plants ◽  
Allosteric Inhibitor ◽  
Allosteric Effector ◽  
Incomplete Form ◽  
C3 Photosynthesis

Umbilicus rupestris (pennywort) switches from C3 photosynthesis to an incomplete form of crassulacean acid metabolism (referred to as ‘CAM-idling’) when exposed to water stress (drought). This switch is accompanied by an increase in the activity of phosphoenolpyruvate carboxylase. This enzyme also shows several changes in properties, including a marked decrease in sensitivity to acid pH, a lower Km for phosphoenolpyruvate, very much decreased sensitivity to the allosteric inhibitor malate, and increased responsiveness to the allosteric effector glucose 6-phosphate. The Mr of the enzyme remains unchanged, at approx. 185 000. These changes in properties of phosphoenolpyruvate carboxylase are discussed in relation to the roles of the enzyme in C3 and in CAM plants.

Carbohydrate partitioning in the leaves of Bromeliaceae performing C3 photosynthesis or Crassulacean acid metabolism

1998 ◽  
Vol 25 (3) ◽  
pp. 371 ◽  
Author(s):  
John T. Christopher ◽  
Joseph A. M. Holtum
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Soluble Sugars ◽  
Carbohydrate Accumulation ◽  
Carbohydrate Partitioning ◽  
C3 Species ◽  
C3 Photosynthesis ◽  
Cam Species

Carbohydrate accumulation was measured in the leaves of 11 speciesrepresenting the three subfamilies of Bromeliaceae. In the Tillandsioideae the C3 species Vriesea carinata Wawra accumulated starch and sucrose while the Crassulacean acid metabolism (CAM)species Tillandsia tricolor Schlechtendal & Chamissoaccumulated mainly starch. In the Pitcairnioideae the C3species Pitcairnia paniculata Ruiz & Pavon and two CAM species Dyckia sp. andFosterella schidosperma Barker accumulated sucrose butnot starch. Of six CAM species in the Bromelioideae, threeCryptanthus zonatus (Visiani) Beer,Neoregalia spectabilis Moore andPortea petropolitana Wawra accumulated starch but notsoluble sugars while three (Ananus comosus Linnaeus,Orthophytum vagans M.B. Foster andNidularium bilbergioides Schultes filius) accumulatedstarch as well as soluble sugars. Carbohydrate accumulation patterns weresimilar for species within each subfamily in that the Pitcairnioideae speciesdid not accumulate starch but accumulated sucrose while species from theTillandsioideae and Bromelioideae all accumulated starch (some alsoaccumulated soluble sugars). Carbohydrate accumulation patterns were notsimilar for C3 species versus CAM species from thedifferent subfamilies. These data suggest that variations in carbohydratebiochemistry resulting from different evolutionary histories have a greaterinfluence on carbohydrate accumulation patterns in CAM bromeliads than theconstraints of the CAM pathway itself.

scholarly journals The Evolution of CAM Photosynthesis in Australian Calandrinia Reveals Lability in C3+CAM Phenotypes and a Possible Constraint to the Evolution of Strong CAM

2019 ◽  
Vol 59 (3) ◽  
pp. 517-534 ◽  
Author(s):  
Lillian P Hancock ◽  
Joseph A M Holtum ◽  
Erika J Edwards
Keyword(s):  
Life Cycle ◽  
Crassulacean Acid Metabolism ◽  
Arid Regions ◽  
Acid Metabolism ◽  
Annual Life Cycle ◽  
Evolutionary Trajectory ◽  
Australian Continent ◽  
C3 Photosynthesis ◽  
Multiple Species ◽  
Cam Photosynthesis

Abstract Australian Calandrinia has radiated across the Australian continent during the last 30 Ma, and today inhabits most Australian ecosystems. Given its biogeographic range and reports of facultative Crassulacean acid metabolism (CAM) photosynthesis in multiple species, we hypothesized (1) that CAM would be widespread across Australian Calandrinia and that species, especially those that live in arid regions, would engage in strong CAM, and (2) that Australian Calandrinia would be an important lineage for informing on the CAM evolutionary trajectory. We cultivated 22 Australian Calandrinia species for a drought experiment. Using physiological measurements and δ13C values we characterized photosynthetic mode across these species, mapped the resulting character states onto a phylogeny, and characterized the climatic envelopes of species in their native ranges. Most species primarily utilize C3 photosynthesis, with CAM operating secondarily, often upregulated following drought. Several phylogenetically nested species are C3, indicating evolutionary losses of CAM. No strong CAM was detected in any of the species. Results highlight the limitations of δ13C surveys in detecting C3+CAM phenotypes, and the evolutionary lability of C3+CAM phenotypes. We propose a model of CAM evolution that allows for lability and reversibility among C3+CAM phenotypes and C3 and suggest that an annual life-cycle may preclude the evolution of strong CAM.

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