Facultative crassulacean acid metabolism (CAM) in four small C3 and C4 leaf-succulents

2017 ◽  
Vol 65 (2) ◽  
pp. 103 ◽  
Author(s):  
Klaus Winter ◽  
Joseph A. M. Holtum
Keyword(s):  
Gas Exchange ◽  
Crassulacean Acid Metabolism ◽  
Native Species ◽  
Acid Metabolism ◽  
Titratable Acidity ◽  
Co2 Uptake ◽  
Drought Treatment ◽  
Whole Plant ◽  
Type Pattern ◽  
Net Co2 Uptake

Measurements of whole-plant gas exchange and titratable acidity demonstrate that the Australian native species Anacampseros australiana J.M.Black (Anacampserotaceae), Crassula sieberiana (Schult. & Schult.f.) Druce (Crassulaceae) and Portulaca australis Endl. (Portulacaceae) and the widespread naturalised tropical exotic, Portulaca pilosa L., exhibit facultative crassulacean acid metabolism (CAM). In well-watered plants, net CO2 uptake was restricted to the daylight hours and occurred via the C3 pathway (A. australiana and C. sieberiana) or the C4 pathway (P. australis and P. pilosa). Leaves of well-watered plants did not accumulate titratable acidity during the night. Following drought treatment, CO2 uptake in the light by shoots decreased markedly, nocturnal gas-exchange shifted from net CO2 loss to a CAM-type pattern that included net CO2 uptake, and leaves acidified at night. Nocturnal CO2 uptake by shoots and leaf acidification were most pronounced in A. australiana and least so in C. sieberiana. The induction of dark CO2 uptake and tissue acidification was fully reversible in all four species: upon rewatering, nocturnal CO2 uptake and acidification ceased and the rates of CO2 incorporation in the light were restored. We suggest that, hitherto considered relatively exceptional globally, facultative CAM may be more common than previously suspected, particularly among the generally small ephemeral leaf-succulents that characterise Australia’s succulent flora.

Degrees of crassulacean acid metabolism in tropical epiphytic and lithophytic ferns

1999 ◽  
Vol 26 (8) ◽  
pp. 749 ◽  
Author(s):  
Joseph A.M. Holtum ◽  
Klaus Winter
Keyword(s):  
Carbon Isotope ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Dark Period ◽  
Titratable Acidity ◽  
Isotope Ratios ◽  
Light Period ◽  
Co2 Uptake ◽  
Carbon Isotope Ratios ◽  
Net Co2 Uptake

Crassulacean acid metabolism (CAM) was observed in three species of tropical ferns, the epiphytes Microsorium punctatum and Polypodium crassifolium and the lithophyte Platycerium veitchii. Polypodium crassifolium and P. veitchii exhibited characteristics of weak CAM. Although no net nocturnal CO2 uptake was observed, the presence of CAM was inferred from nocturnal increases in titratable acidity of 4.7 and 4.1 µequiv (g fr wt)–1 respectively, a reduction in the rates of net CO2 evolution during the first half of the dark period, and the presence of a CAM-like decrease in net CO2 uptake during the early light period. In M. punctatum net CO2 uptake during the first half of the dark period was accompanied by an increase in titratable acidity of 39.2 µequiv (g fr wt)–1 and a pronounced reduction in net CO2 uptake during the early light period. When water was withheld from P. crassifolium and M. punctatum, net CO2 uptake during the light was reduced markedly but there was no change in the extent or patterns of CO2 exhange in the dark. As a consequence, the proportion of carbon gained due to CO2 fixation in the dark increased from 2.8 and 10% to 63.5 and 49.3%, respectively (100% being net CO2 uptake during the light plus the estimated CO2 uptake during the dark). After 9 days without added water, dark CO2 uptake was responsible for the maintenance of a net 24 h carbon gain in P. crassifolium. Platycerium veitchii, P. crassifolium and M. punctatum exhibited carbon isotope ratios of between –25.9 and –22.6‰ indicating that carbon isotope ratios may not, by themselves, be sufficient for the identification of weak CAM. We suggest that CAM may be more prevalent in tropical epiphytic and lithophytic ferns than currently envisaged.

Historical aspects and net CO2 uptake for cultivated Crassulacean acid metabolism plants in Mexico

2002 ◽  
Vol 140 (2) ◽  
pp. 133-142 ◽  
Author(s):  
PARK S NOBEL ◽  
EULOGIO PIMIENTA-BARRIOS ◽  
JULIA ZANUDO HERNANDEZ ◽  
BLANCA C RAMIREZ-HERNANDEZ
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Co2 Uptake ◽  
Historical Aspects ◽  
Net Co2 Uptake

Identification of Rhythmic Subsystems in the Circadian Cycle of Crassulacean Acid Metabolism under Thermoperiodic Perturbations

2003 ◽  
Vol 384 (5) ◽  
pp. 721-728 ◽  
Author(s):  
A. Bohn ◽  
S. Hinderlich ◽  
M.-T. Hütt ◽  
F. Kaiser ◽  
U. Lüttge
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Intercellular Co2 Concentration ◽  
Continuous Light ◽  
Co2 Concentration ◽  
Co2 Uptake ◽  
Frequency Spectra ◽  
Temperature Cycles ◽  
Net Co2 Uptake ◽  
Periodic Temperature

AbstractLeaves of the Crassulacean acid metabolism (CAM) plant Kalanchoë daigremontiana Hamet et Perrier de la Bâthie show overt circadian rhythms in net CO2 uptake, leaf conductance to water and intercellular CO2 concentration, which are entrained by periodic temperature cycles. To probe their sensitivity to thermoperiodic perturbations, intact leaves were exposed to continuous light intensity and temperature cycles with a period of 16 h, applying a set of different baseline temperatures and thermodriver amplitudes. All three overt rhythms were analyzed with respect to their frequency spectra and their phase relations with the thermodriver. For most stimulation protocols, stomatal conductance and net CO2 change were fully or partially entrained by the temperature pulses, while the internal CO2 concentration remained dominated by oscillations in the circadian range. Prolonged time series recorded for up to 22 d in continuous light underline the robustness of these circadian oscillations. This suggests that the overt circadian rhythm of net CO2 uptake in CAM results from the interaction of two coupled original systems: (i) an endogenous cycle of CO2 fixation in the mesophyll, showing very robust periodic activity, and (ii) stomatal movements that respond to environmental stimuli independently of rhythmic processes in the mesophyll, and thus modulate the gas exchange amplitude.

Short-term plasticity of crassulacean acid metabolism expression in the epiphytic bromeliad Tillandsia usneoides

2002 ◽  
Vol 29 (6) ◽  
pp. 749 ◽  
Author(s):  
Richard Haslam ◽  
Anne Borland ◽  
Howard Griffiths
Keyword(s):  
Phase I ◽  
Carbon Balance ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Rapid Change ◽  
Co2 Uptake ◽  
Short Term Plasticity ◽  
Non Invasive ◽  
Tillandsia Usneoides

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. The regulation and flexibility of the crassulacean acid metabolism (CAM) pathway has been investigated in the 'extreme epiphyte' Tillandsia usneoides (L.). Submerging strands of T. usneoides under water, thereby inhibiting the supply of atmospheric CO2, allowed non-invasive in vivo manipulation of the supply of CO2 during the nocturnal Phase I of CAM. Once the plants were removed from submersion, T. usneoides maintained open stomata, and net CO2 uptake occurred throughout most of the photoperiod. Variability in the expression of CAM allowed T. usneoides to compensate for restricted CO2 availability through Phase I of CAM by adjusting gas exchange rates through the photoperiod and subsequent dark period to maintain a constant internal supply of CO2 in the light. Furthermore, T. usneoides demonstrated a gradual, rather than rapid, change in phosphoenolpyruvate carboxylase (PEPC) activation across the day-night cycle, such that PEPC and Rubisco appear to work in tandem in order to maintain carbon balance for this extreme atmospheric bromeliad.

scholarly journals Effects of Day Length on Gas Exchange Characteristics in Crassulacean Acid Metabolism Plant, Dendrobium Ekapol cv. Panda.

1995 ◽  
Vol 64 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Fumiaki SEKIZUKA ◽  
Akihiro NOSE ◽  
Yoshinobu KAWAMITSU ◽  
Seiichi MURAYAMA ◽  
Ken-ichi ARISUMI
Keyword(s):  
Gas Exchange ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Day Length ◽  
Crassulacean Acid Metabolism Plant ◽  
Gas Exchange Characteristics

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

2005 ◽  
Vol 32 (5) ◽  
pp. 397 ◽  
Author(s):  
Katia Silvera ◽  
Louis S. Santiago ◽  
Klaus Winter
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Native Species ◽  
Acid Metabolism ◽  
Carbon Isotopic Composition ◽  
Bimodal Distribution ◽  
Carbon Isotopic ◽  
Acid Accumulation ◽  
Selection For ◽  
Cam Photosynthesis ◽  
Nocturnal Acid Accumulation

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.

Regulation of Rubisco activity in crassulacean acid metabolism plants: better late than never

2002 ◽  
Vol 29 (6) ◽  
pp. 689 ◽  
Author(s):  
Kate Maxwell ◽  
Howard Griffiths ◽  
Brent Helliker ◽  
Andrew Roberts ◽  
Richard P. Haslam ◽  
...  
Keyword(s):  
Electron Transport ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Rubisco Activase ◽  
Light Period ◽  
Phase Iii ◽  
Co2 Uptake ◽  
Rubisco Activity ◽  
Free Atmosphere ◽  
Phase Iv

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. The diurnal regulation of Rubisco was compared for a range of crassulacean acid metabolism (CAM) species in the context of high carboxylation and electron transport capacities, which may be an order of magnitude greater than rates of net CO2 uptake. Early in the light period, Rubisco activity and electron transport were limited when phosphoenolpyruvate carboxylase (PEPC) may have been operating, and maximal extractable activities and activation state for Rubisco were achieved at the end of Phase III, prior to the direct atmospheric uptake of CO2 during Phase IV. The delayed activation was associated with levels of Rubisco activase protein, which reached a maximum at midday, and may account for this pattern of Rubisco activation. This regulation may be modified by environmental conditions - processes that tend to restrict PEPC activity, such as drought stress or incubation of leaves overnight in an oxygen-free atmosphere, release Rubisco from inhibition early in the light period. The quantum yield of light use also tracks Rubisco carboxylation, being particularly low at dawn when PEPC is active. The plasticity in expression of the CAM cycle is therefore matched by the regulation of key carboxylases, with extractable Rubisco activity maximal when drawdown of atmospheric CO2 to cells in succulent CAM tissues is most likely to limit photon utilization shortly after midday, during Phase IV.

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