Environmental control of crassulacean acid metabolism in Welwitschia mirabilis Hook. Fil. in its range of natural distribution in the Namib desert

@article{Schulze2004EnvironmentalCO,
  title={Environmental control of crassulacean acid metabolism in Welwitschia mirabilis Hook. Fil. in its range of natural distribution in the Namib desert},
  author={E. -D. Schulze and Hubert Ziegler and Willibald Stichler},
  journal={Oecologia},
  year={2004},
  volume={24},
  pages={323-334}
}
SummaryWithin the area of its natural distribution in South West Africa, Welwitschia mirabilis has a less negative δ13C value than C3 plants and a more negative δ13C value than C4 species. This indicates that Welwitschia m. assimilates CO2 partially via CAM when growing in its natural habitat. The difference between the δ13C values of Welwitschia m. and of the C3 species is significant in the savanna, whereas it is only small and statistically not significant in the grassland zone. The… 
CO2 gas exchange and transpiration of Welwitschia mirabilis Hook. fil. in the central Namib desert
TLDR
The diurnal CO2 balance indicates that the old leaf parts live at the expense of the younger ones, and the δ13C values are in the range of-17.77 to-19.64‰, which is high for a C3 plant under arid conditions.
Welwitschia mirabilis: CAM or not CAM - what is the answer?
After more than 20 years of extensive study we found clear evidence that Welwitschia mirabilis Hook.f. is able to take up CO2 at night in both of its natural ecosystems, the Namib desert and the
A baseline assessment of the photosynthetic potential of Welwitschia mirabilis using the JIP-test for monitoring and conservation purposes
TLDR
PIABS values can serve as a baseline for future long-term monitoring studies to detect any changes in the health status of W. mirabilis that might result from land use change.
Long-term growth patterns of Welwitschia mirabilis, a long-lived plant of the Namib Desert (including a bibliography)
TLDR
The knowledge gaps and needs for further ecological studies, including the continuation of the LTER programme, are indicated, to elucidate the reproductive output, seed dispersal, recruitment, water availability, age structure, and ecological differences between the sexes, and long-term life history strategies of this unique Namib Desert perennial.
Roots point to water sources of Welwitschia mirabilis in a hyperarid desert
Welwitschia mirabilis is a long‐lived evergreen in the hyperarid Namib Desert; at our study site, rainfall is rare (mean annual precipitation = 31 mm), groundwater deep (57–75 m), and fog frequent
Water Relations, CO2 Exchange, Water-use Efficiency and Growth of Welwitschia mirabilis Hook. fil. in three Contrasting Habitats of the Namib Desert1
TLDR
CO2 exchange, transpiration and leaf water potential of Welwitschia mirabilis were measured in three contrasting habitats of the Namib desert and stomatal conductance, internal CO2concentration and WUE were calculated.
Carbon and nitrogen isotope ratios of mistletoes growing on nitrogen and non-nitrogen fixing hosts and on CAM plants in the Namib desert confirm partial heterotrophy
TLDR
Xylem-tapping mistletoe species growing on Mimosaccae, non-Mimosaceae and hosts performing Crassulacean acid metabolism (CAM) were studied along an aridity gradient in the Namib desert and it was calculated that about 60% of the carbon in mistletoes growing on C3 and on CAM hosts originated from the host.
Estimates of nitrogen fixation by trees on an aridity gradient in Namibia
TLDR
N2 fixation was associated with reduced intrinsic water use efficiency and higher δ15N-values of Mimosaeae are associated with lower carbon isotope ratios (δ13C value), while the opposite trends were found in non-Mimosaceae, in which N-concentration increased with δ 15N, but δ12C was unaffected.
Bienertia cycloptera Bunge ex Boiss., Chenopodiaceae, another C4 Plant without Kranz Tissues286
TLDR
The hypothesis is developed that in species or groups of taxa specific leakages of their C4 systems do occur and this corresponds well with the variance in data from different individuals and populations.
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References

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Der Säurestoffwechsel von Welwitschia mirabilis Hook. Fil. Am Natürlichen Standort in der Namib Wüste
TLDR
It was concluded, after an analysis of temperature conditions, that cool night temperatures were possibly responsible for promoting a greater portion of CAM in Welwitschia m.
Carbon isotope discrimination in alpine succulent plants supposed to be capable of crassulacean acid metabolism (CAM)
TLDR
The δ13C value of the 8 alpine Sedum species examined in this study was much more negative than in the Sempervivum spp.
Diurnaler Säurerhythmus bei Tillandsia usneoides: Untersuchungen über den Weg des Kohlenstoffs sowie die Abhängigkeit des CO2-Gaswechsels von Lichtintensität, Temperatur und Wassergehalt der Pflanze
SummaryTillandsia usneoides, in the common sense a non-succulent plant, exhibits CO2 exchange characterized by net CO2 dark fixation during the night and depression of CO2 exchange during the day.
Carbon Isotope Discrimination in Photosynthesis of CAM Plants
SUCCULENT plants capable of Crassulacean acid metabolism (CAM) show extremely variable carbon isotope discrimination ratios1,2. This ratio, usually expressed as a δ13C value referred to a standard3,
The Gas Exchange Patterns of CAM Plants
The gas exchange patterns of CAM plants are discussed with particular reference to the diurnal changes in the CO2 flux. A model is proposed in which the variations of this pattern between species is
Feinstruktur und Crassulaceen-Säurestoffwechsel in Blättern von Mesembryanthemum crystallinum während natürlicher und NaCl-induzierter Alterung
TLDR
Not only the described changes in fine structure but also the altered CO2 gas exchange reactions take place when glycophytic control plants grow older, thus indicating that NaCl may accelerate the normal ageing process in Mesembryanthemum crystallinum.
Environmental Control of Photosynthetic Options in Crassulacean Plants
TLDR
Evidence suggesting that dark fixation is basically a C4-like process and light fixation is essentially a C3-like photosynthetic process is presented is presented.
Welwitschia mirabilis: observations on cuticular efficiency, a comparative study
Experiments were carried out to determine the effects of removal of the cuticle on loss af water from the leaves of Welwitschia mirabilis, a longlived gymnosperm-like vascular plant endemic to the
THE KRANZ SYNDROME IN THE GRAMINEAE AS INDICATED BY CARBON ISOTOPIC RATIOS
TLDR
All subfamilies, tribes, and genera seem to be uniformly all Kranz or non-Kranz except the subfamily Panicoideae and the genus Palicurn which have both KranZ and non-kranz species represented.
THE OCCURRENCE OF A PERIPHERAL RETICULUM IN PLASTIDS OF THE GYMNOSPERM, WELWITSCHIA MIRABILIS
SUMMARY In cells bordering the vascular bundles of the cotyledons of Welwitschia mirabilis there are starch-containing chloroplasts which possess a type of peripheral reticulum.
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