scholarly journals Corrigendum to: Does the C4 plant Trianthema portulacastrum (Aizoaceae) exhibit weakly expressed crassulacean acid metabolism (CAM)?

2021 ◽  
Vol 48 (12) ◽  
pp. 1315
Author(s):  
Klaus Winter ◽  
Milton Garcia ◽  
Aurelio Virgo ◽  
Jorge Ceballos ◽  
Joseph A. M. Holtum
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Co2 Exchange ◽  
Co2 Uptake ◽  
C4 Plant ◽  
Low Level ◽  
Kranz Anatomy ◽  
Trianthema Portulacastrum ◽  
Annual Herb ◽  
Kinetics Of

We examined whether crassulacean acid metabolism (CAM) is present in Trianthema portulacastrum L. (Aizoaceae), a pantropical, salt-tolerant C4 annual herb with atriplicoid-type Kranz anatomy in leaves but not in stems. The leaves of T. portulacastrum are slightly succulent and the stems are fleshy, similar to some species of Portulaca, the only genus known in which C4 and CAM co-occur. Low- level nocturnal acidification typical of weakly expressed, predominantly constitutive CAM was measured in plants grown for their entire life-cycle in an outdoor raised garden box. Acidification was greater in stems than in leaves. Plants showed net CO2 uptake only during the light irrespective of soil water availability. However, nocturnal traces of CO2 exchange exhibited curved kinetics of reduced CO2 loss during the middle of the night consistent with low-level CAM. Trianthema becomes the second genus of vascular land plants in which C4 and features of CAM have been demonstrated to co-occur in the same plant and the first C4 plant with CAM-type acidification described for the Aizoaceae. Traditionally the stems of herbs are not sampled in screening studies. Small herbs with mildly succulent leaves and fleshy stems might be a numerically significant component of CAM biodiversity.

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

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.

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.

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.

Post-illumination CO2 Exchange and Light-induced CO2 Bursts during C4 Photosynthesis

1997 ◽  
Vol 24 (4) ◽  
pp. 517 ◽  
Author(s):  
Agu Laisk ◽  
Gerald E. Edwards
Keyword(s):  
Malic Enzyme ◽  
Co2 Exchange ◽  
Co2 Uptake ◽  
Low Light ◽  
Co2 Response ◽  
Amaranthus Cruentus ◽  
Dark Light ◽  
Gas System ◽  
Detailed Kinetics ◽  
Kinetics Of

Detailed kinetics of the post-illumination CO2 exchange, and darklight transients following post-illumination exchange, were measured in leaves of Sorghum bicolor, a NADP-malic enzyme (NADP-ME), and Amaranthus cruentus, a NAD-malic enzyme (NAD-ME) type C4 plant using a gas system that has a full-response time of 3.5 s. The amount of CO2 fixed in the dark (assimilatory charge, AC) was up to 200 µmol m-2 for A. cruentus and 350-450 µmol m-2 for S. bicolor. AC was at its maximum value at CO2 concentrations close to the inflection of the CO2 response curve, and decreased when photosynthesis was limited by low light intensity. The kinetics of post-illumination CO2 fixation indicate that the rate of carboxylation in the C4 cycle is limited by the supply of phosphoenolpyruvate. In A. cruentus, under saturating CO2 the post-illumination CO2 uptake was replaced by a burst (68 µmol m-2). In S. bicolor, the dark-light induction commenced with a rapid CO2 burst (less than 5 s) of 46 µmol m-2, followed by a gulp. The observed CO2 transients show imbalances in the C4 and C3 cycles. In S. bicolor the lack of a post-illumination burst, and the presence of the light- induced CO2 burst is taken as evidence for strict coupling of malate decarboxylation to PGA reduction in NADP-ME species; the opposite response in A. cruentus indicates the lack of strict coupling between the C4 and C3 cycle in NAD-ME species.

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