Crassulacean Acid Metabolism in Roots of a Leafless Orchid, Campylocentrum tyrridion Garay &amp; Dunsterv.

Winter, Klaus; Medina, Ernesto; García, Víctor Jiménez; Mayoral, Maria Luisa; Muniz, R.

doi:10.1016/s0176-1617(85)80166-8

Cited by 47 publications

(21 citation statements)

References 10 publications

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“…Chase (1986) and Benzing (1990) therefore postulate that the restriction of species to twigs might reflect tolerances for certain moisture levels. On young bare twigs, humidity is low, whereas humidity increases on older branches with thicker layers of substrate (Winter et al 1985).…”

Section: Discussionmentioning

confidence: 99%

Epiphytism and pollinator specialization: drivers for orchid diversity?

Gravendeel

Smithson

Slik

et al. 2004

Phil. Trans. R. Soc. Lond. B

199

152

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Epiphytes are a characteristic component of tropical rainforests. Out of the 25 000 orchid species currently known to science, more than 70% live in tree canopies. Understanding when and how these orchids diversified is vital to understanding the history of epiphytic biomes. We investigated whether orchids managed to radiate so explosively owing to their predominantly epiphytic habit and/or their specialized pollinator systems by testing these hypotheses from a statistical and phylogenetic standpoint. For the first approach, species numbers of 100 randomly chosen epiphytic and terrestrial genera were compared. Furthermore, the mean number of pollinators per orchid species within the five subfamilies was calculated and correlated with their time of diversification and species richness. In the second approach, molecular epiphytic orchid phylogenies were screened for clades with specific suites of epiphytic adaptations. Epiphytic genera were found to be significantly richer in species than terrestrial genera both for orchids and non-orchids. No evidence was found for a positive association between pollinator specialization and orchid species richness. Repeated associations between a small body size, short life cycle and specialized clinging roots of twig epiphytes in Bulbophyllinae and Oncidiinae were discovered. The development of twig epiphytism in the first group seems repeatedly correlated with speciation bursts.

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Section: Discussionmentioning

confidence: 99%

Epiphytism and pollinator specialization: drivers for orchid diversity?

Gravendeel

Smithson

Slik

et al. 2004

Phil. Trans. R. Soc. Lond. B

199

152

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“…1). The rate of nocturnal CO 2 assimilation is governed by mesophyll processes, such as regulation of carbohydrate storage reserves (Cushman et al 2008a) or vacuolar storage capacity, rather than stomatal conductance (Winter 1985;Winter et al 1985). Depending on the CAM species, a variety of storage carbohydrates (e.g.…”

Section: Phases Of Cammentioning

confidence: 99%

Evolution along the crassulacean acid metabolism continuum

Silvera

Neubig

Whitten

et al. 2010

Functional Plant Biol.

192

199

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Abstract. Crassulacean acid metabolism (CAM) is a specialised mode of photosynthesis that improves atmospheric CO 2 assimilation in water-limited terrestrial and epiphytic habitats and in CO 2 -limited aquatic environments. In contrast with C 3 and C 4 plants, CAM plants take up CO 2 from the atmosphere partially or predominantly at night. CAM is taxonomically widespread among vascular plants and is present in many succulent species that occupy semiarid regions, as well as in tropical epiphytes and in some aquatic macrophytes. This water-conserving photosynthetic pathway has evolved multiple times and is found in close to 6% of vascular plant species from at least 35 families. Although many aspects of CAM molecular biology, biochemistry and ecophysiology are well understood, relatively little is known about the evolutionary origins of CAM. This review focuses on five main topics: (1) the permutations and plasticity of CAM, (2) the requirements for CAM evolution, (3) the drivers of CAM evolution, (4) the prevalence and taxonomic distribution of CAM among vascular plants with emphasis on the Orchidaceae and (5) the molecular underpinnings of CAM evolution including circadian clock regulation of gene expression.

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“…However, this is not the case of shootless orchids, where roots assume most or full responsibility for carbon gain for the whole plant, besides mineral uptake and assimilation. Compared to roots of leafy plants, they usually have a thinner velamen layer and larger, chloroplast-containing parenchyma cells in the cortex (Benzing et al, 1983;Benzing & Ott, 1981;Winter et al, 1985). The presence of CAM in roots appeared more common in this type of orchid compared to leafy ones, as demonstrated by Benzing & Ott (1981).…”

Section: Photosynthesis In Aerial Roots Of Shootless Orchidsmentioning

confidence: 94%