Distribution of crassulacean acid metabolism in orchids of Panama: evidence of selection for weak and strong modes

Crassulacean acid metabolism (CAM) is one of three metabolic pathways found in vascular plants for the assimilation of carbon dioxide. In this study, we investigate the occurrence of CAM photosynthesis in 200 native orchid species from Panama and 14 non-native species by carbon isotopic composition (δ13C) and compare these values with nocturnal acid accumulation measured by titration in 173 species. Foliar δ13C showed a bimodal distribution with the majority of species exhibiting values of approximately –28‰ (typically associated with the C3 pathway), or –15‰ (strong CAM). Although thick leaves were related to δ13C values in the CAM range, some thin-leaved orchids were capable of CAM photosynthesis, as demonstrated by acid titration. We also found species with C3 isotopic values and significant acid accumulation at night. Of 128 species with δ13C more negative than –22‰, 42 species showed nocturnal acid accumulation per unit fresh mass characteristic of weakly expressed CAM. These data suggest that among CAM orchids, there may be preferential selection for species to exhibit strong CAM or weak CAM, rather than intermediate metabolism.

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CO2 starvation experiments provide support for the carbon-limited hypothesis on the evolution of CAM-like behaviour in Isoëtes

Annals of Botany ◽

10.1093/aob/mcaa153 ◽

2020 ◽

Vol 127 (1) ◽

pp. 135-141

Author(s):

Jacob S Suissa ◽

Walton A Green

Keyword(s):

Aquatic Ecosystems ◽

Crassulacean Acid Metabolism ◽

Acid Metabolism ◽

Selective Pressure ◽

Atmospheric Co2 ◽

Terrestrial Plants ◽

Cam Plants ◽

Acid Accumulation ◽

Use Efficiency ◽

Nocturnal Acid Accumulation

Abstract Background and Aims Crassulacean acid metabolism (CAM) is an adaptation to increase water use efficiency in dry environments. Similar biochemical patterns occur in the aquatic lycophyte genus Isoëtes. It has long been assumed and accepted that CAM-like behaviour in these aquatic plants is an adaptation to low daytime carbon levels in aquatic ecosystems, but this has never been directly tested. Methods To test this hypothesis, populations of Isoëtes engelmannii and I. tuckermanii were grown in climate-controlled chambers and starved of atmospheric CO2 during the day while pH was measured for 24 h. Key Results We demonstrate that terrestrial plants exposed to low atmospheric CO2 display diel acidity cycles similar to those in both xerophytic CAM plants and submerged Isoëtes. Conclusions Daytime CO2 starvation induces CAM-like nocturnal acid accumulation in terrestrial Isoëtes, substantiating the hypothesis that carbon starvation is a selective pressure for this physiological behaviour.

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Effects of photoperiod and drought on the induction of crassulacean acid metabolism and the reproduction of plants of Talinum triangulare

Canadian Journal of Botany ◽

10.1139/b99-036 ◽

1999 ◽

Vol 77 (3) ◽

pp. 404-409 ◽

Cited By ~ 3

Author(s):

A Herrera

Keyword(s):

Crassulacean Acid Metabolism ◽

Reproductive Effort ◽

Acid Metabolism ◽

Day Length ◽

Tropical Species ◽

Leaf Water Content ◽

Acid Accumulation ◽

Nocturnal Acid Accumulation ◽

Talinum Triangulare ◽

Short Days

To examine the effects of day length on the induction of crassulacean acid metabolism (CAM) by drought in the tropical species, Talinum triangulare (Jacq.) Willd. (Portulacaceae), plants were subjected to drought under different photoperiods. Nocturnal acid accumulation was 52 µmol H+··g-1 fresh mass (FM) in plants grown under a 10 h light : 14 h dark photoperiod and 76 µmol H+·g-1 FM in plants grown under 13 h light : 11 h dark, whereas it was only 10 µmol H+·g-1 FM in plants grown under 18 h light : 6 h dark. Plants were subjected to drought under short days and under short days with a night interruption of 1.5 h white light, aiming to simulate a long day, while minimally affecting daily carbon balance. Only droughted plants under normal short days accumulated acids during the night. Absence of CAM could not be attributed to differences due to photoperiod in either biomass allocation, chlorophyll content, or leaf water content. Photoperiod did not significantly affect fecundity in watered plants, whereas drought markedly reduced fecundity in plants with night interruption relative to plants under normal short days. Reproductive effort, calculated as seeds per gram leaf, was significantly higher in droughted plants under normal short days and watered plants with and without night interruption than in droughted plants with night interruption.Key words: CAM, crassulacean acid metabolism, drought, fecundity, induction, photoperiod, reproductive effort, reproduction, Talinum triangulare

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A relationship between fecundity, survival, and the operation of crassulacean acid metabolism in Talinum triangulare

Canadian Journal of Botany ◽

10.1139/b98-136 ◽

1998 ◽

Vol 76 (11) ◽

pp. 1908-1915 ◽

Cited By ~ 2

Author(s):

María Angélica Taisma ◽

Ana Herrera

Keyword(s):

Life History ◽

Life Table ◽

Water Deficit ◽

Crassulacean Acid Metabolism ◽

Reproductive Effort ◽

Acid Metabolism ◽

Significant Rise ◽

Acid Accumulation ◽

Nocturnal Acid Accumulation ◽

Talinum Triangulare

In plants of the perennial, deciduous herb Talinum triangulare, crassulacean acid metabolism (CAM) is induced by drought; therefore, CAM may be an adaptation to water deficit in this species. The present study was undertaken to determine the effects of water deficit on fecundity and CAM in plants of T. triangulare. Plants were grown from seed in the greenhouse and the life table was constructed with dynamic cohorts. CAM was induced by drought in plants as young as 45 days old, and its induction was associated with a significant rise in fecundity; values of survival beta mean fecundity by age-class were 30-50% higher in plants subjected to drought than in control plants due to a rise in fecundity. Plants subjected to drought produced more and lighter seeds, which germinated faster than their watered controls. These characteristics could be advantageous for a colonizing species such as T. triangulare. Plants obtained from the germination of seeds of plants subjected to drought did not show higher values of nocturnal acid accumulation when subjected to drought than the droughted offspring of watered plants but they showed higher survival and an earlier and higher reproductive effort than plants obtained from the germination of seeds of watered plants. The fact that values of survival beta mean fecundity were higher in plants subjected to drought than in watered plants suggests, within the context of the life history, that characters associated with the CAM syndrome may be adaptive.Key words: fitness, inducible CAM, life table.

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Relationships between Photosynthetically Active Radiation, Nocturnal Acid Accumulation, and CO2 Uptake for a Crassulacean Acid Metabolism Plant, Opuntia ficus-indica

PLANT PHYSIOLOGY ◽

10.1104/pp.71.1.71 ◽

1983 ◽

Vol 71 (1) ◽

pp. 71-75 ◽

Cited By ~ 82

Author(s):

Park S. Nobel ◽

Terry L. Hartsock

Keyword(s):

Photosynthetically Active Radiation ◽

Crassulacean Acid Metabolism ◽

Acid Metabolism ◽

Co2 Uptake ◽

Opuntia Ficus Indica ◽

Active Radiation ◽

Acid Accumulation ◽

Crassulacean Acid Metabolism Plant ◽

Nocturnal Acid Accumulation

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Mode of photosynthesis during different life stages of hemiepiphytic Clusia species

Functional Plant Biology ◽

10.1071/pp01206 ◽

2002 ◽

Vol 29 (6) ◽

pp. 725 ◽

Cited By ~ 14

Author(s):

Wolfgang Wanek ◽

Werner Huber ◽

Stefan K. Arndt ◽

Marianne Popp

Keyword(s):

Crassulacean Acid Metabolism ◽

Acid Metabolism ◽

Developmental Stages ◽

Growth Stages ◽

Life Stages ◽

Lowland Tropical Forest ◽

Acid Accumulation ◽

Plant Growth Stages ◽

Nocturnal Acid Accumulation ◽

Carbon Economy

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. Carbon isotope fractionation and nocturnal acid accumulation in Clusia osaensis Hammel-ined., C. �peninsulae Hammel-ined. and C. valerii Standl. were investigated during the seedling, epiphytic and hemiepiphytic phases in a lowland tropical forest in Costa Ricato study photosynthetic adaptations of different plant growth stages to their habitat. Foliar δ 13C values around -24 to -32‰ indicate predominant C3 fixation of CO2 and low crassulacean acid metabolism (CAM) activity in all three Clusia species. Only terrestrially rooted plants of C. osaensis showed increased CAM expression. However, all developmental stages exhibited significant CAM cycling as shown by significant day-night fluctuations of titratable protons and of malic and citric acid. In C. valerii and C. peninsulae, an increase in CAM expression with plant development was not observed, and CAM cycling in hemiepiphytic-stage plants was completely repressed during the high rainfall season. The expression of CAM in the three Clusia species is therefore not developmentally controlled but triggered by environmental factors such as water availability and light intensity. These factors remain relatively stable in this ecosystem and CAM is therefore not fully expressed. However, CAM cycling may be of ecophysiological significance in all life stages as it serves as a mechanism to improve carbon economy by reducing respiratory CO2 losses.

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A perspective on crassulacean acid metabolism photosynthesis evolution of orchids on different continents: Dendrobium as a case study

Journal of Experimental Botany ◽

10.1093/jxb/erz461 ◽

2019 ◽

Vol 70 (22) ◽

pp. 6611-6619

Author(s):

Ming-He Li ◽

Ding-Kun Liu ◽

Guo-Qiang Zhang ◽

Hua Deng ◽

Xiong-De Tu ◽

...

Keyword(s):

Crassulacean Acid Metabolism ◽

Middle Miocene ◽

Acid Metabolism ◽

Flowering Plants ◽

Asian Clade ◽

Wide Range ◽

Cam Species ◽

Climatic Cooling ◽

Cam Photosynthesis

Abstract Members of the Orchidaceae, one of the largest families of flowering plants, evolved the crassulacean acid metabolism (CAM) photosynthesis strategy. It is thought that CAM triggers adaptive radiation into new niche spaces, yet very little is known about its origin and diversification on different continents. Here, we assess the prevalence of CAM in Dendrobium, which is one of the largest genera of flowering plants and found in a wide range of environments, from the high altitudes of the Himalayas to relatively arid habitats in Australia. Based on phylogenetic time trees, we estimated that CAM, as determined by δ 13C values less negative than –20.0‰, evolved independently at least eight times in Dendrobium. The oldest lineage appeared in the Asian clade during the middle Miocene, indicating the origin of CAM was associated with a pronounced climatic cooling that followed a period of aridity. Divergence of the four CAM lineages in the Asian clade appeared to be earlier than divergence of those in the Australasian clade. However, CAM species in the Asian clade are much less diverse (25.6%) than those in the Australasian clade (57.9%). These findings shed new light on CAM evolutionary history and the aridity levels of the paleoclimate on different continents.

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Light-responsive expression atlas reveals the effects of light quality and intensity in Kalanchoë fedtschenkoi, a plant with crassulacean acid metabolism

GigaScience ◽

10.1093/gigascience/giaa018 ◽

2020 ◽

Vol 9 (3) ◽

Cited By ~ 1

Author(s):

Jin Zhang ◽

Rongbin Hu ◽

Avinash Sreedasyam ◽

Travis M Garcia ◽

Anna Lipzen ◽

...

Keyword(s):

Light Intensity ◽

White Light ◽

Crassulacean Acid Metabolism ◽

Light Quality ◽

Acid Metabolism ◽

Easy Access ◽

Cam Plants ◽

A Genome ◽

Acid Accumulation ◽

Expression Atlas

Abstract Background Crassulacean acid metabolism (CAM), a specialized mode of photosynthesis, enables plant adaptation to water-limited environments and improves photosynthetic efficiency via an inorganic carbon-concentrating mechanism. Kalanchoë fedtschenkoi is an obligate CAM model featuring a relatively small genome and easy stable transformation. However, the molecular responses to light quality and intensity in CAM plants remain understudied. Results Here we present a genome-wide expression atlas of K. fedtschenkoi plants grown under 12 h/12 h photoperiod with different light quality (blue, red, far-red, white light) and intensity (0, 150, 440, and 1,000 μmol m–2 s–1) based on RNA sequencing performed for mature leaf samples collected at dawn (2 h before the light period) and dusk (2 h before the dark period). An eFP web browser was created for easy access of the gene expression data. Based on the expression atlas, we constructed a light-responsive co-expression network to reveal the potential regulatory relationships in K. fedtschenkoi. Measurements of leaf titratable acidity, soluble sugar, and starch turnover provided metabolic indicators of the magnitude of CAM under the different light treatments and were used to provide biological context for the expression dataset. Furthermore, CAM-related subnetworks were highlighted to showcase genes relevant to CAM pathway, circadian clock, and stomatal movement. In comparison with white light, monochrome blue/red/far-red light treatments repressed the expression of several CAM-related genes at dusk, along with a major reduction in acid accumulation. Increasing light intensity from an intermediate level (440 μmol m−2 s−1) of white light to a high light treatment (1,000 μmol m–2 s–1) increased expression of several genes involved in dark CO2 fixation and malate transport at dawn, along with an increase in organic acid accumulation. Conclusions This study provides a useful genomics resource for investigating the molecular mechanism underlying the light regulation of physiology and metabolism in CAM plants. Our results support the hypothesis that both light intensity and light quality can modulate the CAM pathway through regulation of CAM-related genes in K. fedtschenkoi.

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