Day-night cycles of net CO2 exchange in crassulacean acid metabolism as related to day-night changes of abscisic-acid levels

1988 ◽  
Vol 30 (1) ◽  
pp. 34-41 ◽  
Author(s):  
W. Huiber ◽  
U. Lüttge
Keyword(s):  
Abscisic Acid ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Co2 Exchange

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.

scholarly journals Transcript and metabolite changes during the early phase of abscisic acid-mediated induction of crassulacean acid metabolism in Talinum triangulare

2019 ◽  
Vol 70 (22) ◽  
pp. 6581-6596 ◽  
Author(s):  
Eva Maleckova ◽  
Dominik Brilhaus ◽  
Thomas J Wrobel ◽  
Andreas P M Weber
Keyword(s):  
Abscisic Acid ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Enrichment Analysis ◽  
Titratable Acidity ◽  
Abscisic Acid Metabolism ◽  
Use Efficiency ◽  
Cam Regulation ◽  
Cam Species ◽  
Talinum Triangulare

Abstract Crassulacean acid metabolism (CAM) has evolved as a water-saving strategy, and its engineering into crops offers an opportunity to improve their water use efficiency. This requires a comprehensive understanding of the regulation of the CAM pathway. Here, we use the facultative CAM species Talinum triangulare as a model in which CAM can be induced rapidly by exogenous abscisic acid. RNA sequencing and metabolite measurements were employed to analyse the changes underlying CAM induction and identify potential CAM regulators. Non-negative matrix factorization followed by k-means clustering identified an early CAM-specific cluster and a late one, which was specific for the early light phase. Enrichment analysis revealed abscisic acid metabolism, WRKY-regulated transcription, sugar and nutrient transport, and protein degradation in these clusters. Activation of the CAM pathway was supported by up-regulation of phosphoenolpyruvate carboxylase, cytosolic and chloroplastic malic enzymes, and several transport proteins, as well as by increased end-of-night titratable acidity and malate accumulation. The transcription factors HSFA2, NF-YA9, and JMJ27 were identified as candidate regulators of CAM induction. With this study we promote the model species T. triangulare, in which CAM can be induced in a controlled way, enabling further deciphering of CAM regulation.

Induction and reversal of crassulacean acid metabolism in Calandrinia polyandra: effects of soil moisture and nutrients

2011 ◽  
Vol 38 (7) ◽  
pp. 576 ◽  
Author(s):  
Klaus Winter ◽  
Joseph A. M. Holtum
Keyword(s):  
Crassulacean Acid Metabolism ◽  
Co2 Fixation ◽  
Acid Metabolism ◽  
Co2 Exchange ◽  
Edaphic Conditions ◽  
Whole Plant ◽  
Negative Effect ◽  
Photosynthetic Plasticity ◽  
Dark Co2 Fixation

Calandrinia polyandra Benth. (Montiaceae), an annual succulent herb endemic to Australia, is an exemplary facultative crassulacean acid metabolism (CAM) plant as demonstrated by continuous whole-plant lifetime CO2 exchange measurements under controlled conditions in the laboratory. Reduced soil water availability induced a shift from solely daytime CO2 fixation to dark CO2 fixation. The shift from C3 photosynthesis to CAM was reversible either upon rewatering alone, or upon a combination of rewatering and addition of nutrients. These observations highlight the role of edaphic conditions in controlling CAM expression in a plant that has the option of fixing CO2 either during the day or during the night, providing further evidence that this extreme form of photosynthetic plasticity is primarily controlled by the environment rather than plant ontogeny. The stimulating effect of soil nutrients on CO2 fixation in the light and its negative effect on dark CO2 fixation have not been described previously and deserve further attention. In the most widely used CAM model system, the halophytic Mesembryanthemum crystallinum L., CAM is typically induced by high salinity, and some metabolic responses may be CAM-unrelated and related to salt stress per se. C. polyandra could be an excellent complementary system for studying the biochemical and molecular foundations of CAM because drought stress elicits a complete C3 to CAM transition.

Crassulacean Acid Metabolism and Diurnal Variations of Internal CO2 and O2 Concentrations in Sedum praealtum DC

1979 ◽  
Vol 6 (4) ◽  
pp. 557 ◽  
Author(s):  
MH Spalding ◽  
DK Stumpf ◽  
MSB Ku ◽  
RH Burris ◽  
GE Edwards
Keyword(s):  
Malic Acid ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Dark Period ◽  
Stomatal Closure ◽  
Co2 Concentration ◽  
Co2 Exchange ◽  
C3 Plants ◽  
Cam Plants ◽  
Internal Co2

Internal CO2 and O2 concentrations in Sedum praealtum DC. were determined by gas chromatography of 200-�l gas samples. Day-night monitoring showed that internal CO2 varied from a high of approximately 4000 �l/l during periods of daytime stomatal closure to a low of 270-280 �l/l during the dark period (stomata open). Internal O2 concentrations varied from a high of approximately 26 % at midday to a low of 20.8 % during the dark period. The calculated internal O2/CO2 ratio varied about 12-15-fold from 50-60 near midday to approximately 750 during the dark period (ratio in normal air is roughly 600). Day-night patterns of CO2 exchange and malic acid concentration were typical for a plant with crassulacean acid metabolism (CAM). Influx of CO2 during the late light period was inhibited by O2, but dark CO2 influx was O2-insensitive. Gas samples taken near midday from several CAM plants all showed elevated internal CO2 and O2 concentrations. Ratios of O2/CO2 in these plants ranged from 81 in Sedum praealtum to 285 in Hoya carnosa. The highest internal O2 concentration observed was 41.5% in Kalanchoe gastonis-bonnieri. The high CO2 concentration in leaves of CAM plants during daytime stomatal closure should provide a near- saturating level of this substrate for photosynthesis. In comparison to C3 plants, the relatively low O2/CO2 ratio in the CAM leaf during malic acid decarboxylation should be favourable for photosynthesis and unfavourable for O2 inhibition of photosynthesis.

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