The Occurrence and Phylogenetics of Crassulacean Acid Metabolism in the Portulacaceae

Guralnick, Lonnie J.; Jackson, Michael

doi:10.1086/319569

Cited by 65 publications

(58 citation statements)

References 23 publications

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“…2011). The occurrence of CAM, Kranz anatomy and C 4 photosynthesis in the same leaf has been reported in Portulacaceae (Guralnick and Jackson 2001), but to date no report on CAM together with C 2 photosynthesis has been published. Given that the C 2 route of carbon fixation has been proposed as an intermediate evolutionary step from C 3 to C 4 (Sage et al .…”

Section: Discussionmentioning

confidence: 89%

Crassulacean acid metabolism-cycling in Euphorbia milii

Herrera

2013

AoB Plants

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Photosynthetic characteristics of Euphorbia milii are reported for the first time. The occurrence of CAM-cycling is shown to serve as a mechanism of water conservation. This is a detailed and novel report of such CAM mode in the genus, which is abundant in constitutive CAM and C4 species. Anatomical evidence for the possible operation of a CO2-concentrating mechanism around the vascular bundle, the C2 route, is provided. Findings are important for our understanding of evolution of CAM in the genus.

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Section: Discussionmentioning

confidence: 89%

Crassulacean acid metabolism-cycling in Euphorbia milii

Herrera

2013

AoB Plants

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“…1), these results suggest obligate dependence on CAM in these strong CAM species. On the other hand, the weak CAM designated here can be categorized as facultative CAM, CAM-cycling (Kluge and Ting 1978), or latent CAM (Schuber and Kluge 1981) for a given species (Cushman and Borland 2002;Guralnick and Jackson 2001;Lüttge 2004). However, we cannot specify the categories because measurements of carbon uptake and stomatal conductance under various stresses are needed to identify these modifications.…”

Section: Classification Of Photosynthetic Charactersmentioning

confidence: 99%

“…Gehring et al 1997Gehring et al , 2003Guralnick and Jackson 2001;Vaasen et al 2002;Jones et al 2003;Reinert et al 2003). Taking into account these limitations in previous treatments, we investigated relationships among photosynthetic type, environment of habitat, life form, and phylogenetic relationship of Cymbidium Sw., an orchid group, in which the ecological attributes are greatly diversified.…”

Section: Introductionmentioning

confidence: 99%

The occurrence of crassulacean acid metabolism in Cymbidium (Orchidaceae) and its ecological and evolutionary implications

et al. 2008

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Crassulacean acid metabolism (CAM) is one of the photosynthetic pathways regarded as adaptations to water stress in land plants. Little is known about correlations among the level of CAM activity, environment of habitat, life form, and phylogenetic relationship of a plant group from an evolutionary perspective. We examined these relationships in 18 species of Cymbidium (Orchidaceae) because the genus shows distinctive diversification of habitats and life forms. The photosynthetic type was classed into three categories, strong CAM, weak CAM, and C(3) on the basis of CAM activity. CAM expression in Cymbidium was confined to the epiphytic and lithophytic species. Especially, all of these species from tropical to subtropical rainforest exhibited CAM activity. On the other hand, the terrestrial species always exhibited C(3) metabolism irrespective of their varied habitats. Regarding the evolution of photosynthetic characters, weak CAM was the ancestral state in Cymbidium and strong CAM and C(3) metabolism occurred subsequently. The evolution of strong CAM likely enabled Cymbidium to extend to exposed sites in tropical lowland where marked water stress exists. Further, different levels of CAM activity characterized each species and such potential plasticity of CAM may realize the radiation of Cymbidium into sites with different environmental conditions.

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“…This has the features of CAM cycling, where stomata are kept closed in the night but respiratory CO 2 is re-fixed via phosphoenolpyruvate carboxylase (PEPC) and stored in the form of organic acid (mainly malic acid) as it is typical for the CO 2 dark fixation of CAM, and organic acid decarboxylation provides CO 2 as a substrate for assimilation in the subsequent day (Rayder and Ting 1981;Diaz and Medina 1984;Nobel and Hartsock 1987;Edwards and Diaz 2006). Such CAM-cycling has been suggested to be an initial step in the evolution of full CAM (Guralnick et al 1986;Guralnick and Jackson 2001), where stomata are open during the night and CO 2 is fixed by PEPC and stored in the form of organic acid in the cell vacuoles, and where the organic acid is remobilized again, decarboxylated and the CO 2 regained fixed via ribulosebisophosphate carboxylase/oxygenase (RubisCO) behind closed stomata in the subsequent day. However, among the 17 species of Pereskia only one, i.e.…”

Section: Phylogenetic Relationsmentioning

confidence: 99%

Stem CAM in arborescent succulents

Lüttge

2008

Trees

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Stem CAM with a peripheral chlorenchyma in stem succulents growing up to arborescent sizes and life forms appears to be a unique evolution as it requires delayed and reduced bark formation and stem stomata. However, stem succulence as a convergent morphotype and with it the stem CAM physiotype evolved polyphyletically in many divergent taxa of the dicotyledonous angiosperms. Controlling water budgets is the main ecophysiological benefit of stem succulence and CAM, where the cooperation of a peripheral photosysnthetically active chlorenchyma and a central water storing hydrenchyma is co-ordinately regulated. Thus, a major factor important for performance of stem CAM succulents at the community level is water or drought. Although this implies fitness under osmotic stress, CAM performing stem succulents are not adapted to salinity and are salt stress avoiders where they occur in saline habitats. Notwithstanding the low overall productivity of CAM plants in general, stem CAM plants can show very high productivity under certain circumstances and may also respond to elevated environmental atmospheric CO 2 concentrations with increased growth.

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The Occurrence and Phylogenetics of Crassulacean Acid Metabolism in the Portulacaceae

Cited by 65 publications

References 23 publications

Crassulacean acid metabolism-cycling in Euphorbia milii

Crassulacean acid metabolism-cycling in Euphorbia milii

The occurrence of crassulacean acid metabolism in Cymbidium (Orchidaceae) and its ecological and evolutionary implications

Stem CAM in arborescent succulents

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