The particular form of an animal's adaptation is a specialization that has made it successful in its ecological niche. Secondary compounds are adaptations of plants to their environmental challenges. The same process of natural selection applies to all organisms: more ecologically successful individuals in the population leave more offspring that inherit the genetic basis of their parents' success.
Based upon the free mobility of purine alkaloids through all kind of barriers except the diaspore surface and the in situ complexation by chlorogenic acids, we may hypothesize that caffeine and its allies are distributed within the plant to the extent of CGA formation and accumulation.
Thus, the allocation pattern of the latter may govern the direction and the rate of caffeine fluxes within the coffee plant. Since the complexor concentration is highest in the newly formed organs e. However, active transporters for purines Gillissen et al. Leaf senescence: It is not yet clear to which extent the arabica plant recovers the caffeine nitrogen from the senescing leaf.
However, leaf longevity and seasonal variation of greenhouse conditions may explain the discrepancy between 'adult' and 'old' simply as a result of different life histories. Since caffeine-degrading microorganisms are expected to be part of the plant surface as well as of the endophytic microflora, all reports dealing with degradation or with the time-course of the caffeine concentration in aging leaves must be considered with caution, unless the absence of endophytes was proven and other microbial interferences were excluded.
In our own studies Huber and Baumann, unpublished we were not able to find distinctly lower caffeine levels in shed arabica leaves even when yellow! Of course, substantial degradation of caffeine occurs in liberio-excelsoid coffee leaves even when young Petermann and Baumann, ; Mazzafera et al.
Flowering: Despite much research done on the metabolism during coffee flower development, see e. Vasudeva and Gopal, , the aspect of purine alkaloid allocation is to our knowledge not yet mentioned in literature. I can report here solely on a few analyses we did on petals, stamens and the gynoecium in arabica flowers at anthesis: All these flower parts contained caffeine as main purine alkaloid, around nmol. If we combine all the data available on purine alkaloids in flowers of 'caffeine plants', that is from literature Suzuki, ; Fujimori and Ashihara, , ; Tretyn et al.
It has to be mentioned that also the nectar, as far as analyzed, contains purine alkaloids. Since the average alkaloid concentration in both leaves and flowers is very low, one may speculate that in these species leaf purine alkaloid accumulation is likewise restricted to specific sites such as e. Fruit and seed development: After blossom fall, the remaining ovary develops, under favorable conditions, without delay into the young, rapidly growing green coffee bean which, due to high investments, is protected against predators by several means: The fruits are inapparently clustered in the leaf axil; both chlorogenic acids and purine alkaloids are highly concentrated in the pericarp, and finally, the development of the true, nutrient rich endosperm is postponed in favor of a 'maternal bean' Carvalho et al.
Seemingly, the mother avoids the 'parental conflict' Barton et al. Nevertheless, the metabolites have to be shuffled via the apoplast, generally furnished with a remarkable armada of hydrolytic enzymes. Presumably, the metabolic passage from perisperm into endosperm is besides simple diffusion a highly regulated translocater-assisted process, firmly coordinated with on-the-spot synthesis as well as with import from other sources.
It is one of the most intriguing tasks of the coffee research to explore all the metabolic and regulatory events finally culminating in a coffee bean furnished with a cocktail of substances yielding a pleasant and unique mix after roasting.
Now, back to caffeine! Its final amount and concentration in the true bean is the result of a acquisition from the perisperm, b intrinsic biosynthesis as shown by tracer experiments Keller et al. It may well be, that the extent of a and c is governed in essence, as outlined above, by the allocation of chlorogenic acids. Hence, the regulation of the pathways of these depsides is of key importance.
Mazzafera's group recently showed by RT-PCR, that all the genes coding for chlorogenic acid synthesis are strongly expressed during endosperm development and gradually decline towards maturity Melo and Mazzafera, The concentration of chlorogenic acids was, as expected, highest at the youngest stage.
With respect to the time course of caffeine accumulation in the developing fruit, I refer to the work of Keller et al. Maro R. Since at that time no reports existed on this subject, we firstly decided to established a sophisticated, highly reproducible HPLC system, just in order to separate in one run as much metabolites as possible, and to determine the quantity as well as the UV spectra of all of them.
Coffee beans from seven entities species, varieties, or interspecific crosses were extracted and analysed. More than UV-absorbing substances per sample could be resolved and absolutely or, if unknown, relatively quantified. The data were analysed using a correlation program and essentially yielded the following new insights, which were neither intended nor expected:.
With the today knowledge one could extend the link further to the poly ADP-ribose metabolism Berglund, ; De Block et al.
Of course, the competition for methyl groups is more obvious and less speculative. Additionally, a close look to the data revealed that the minor chlorogenic acids altogether were in molar equivalence to caffeine as if they were physically engaged in the complex without participating at the equilibrium with 5-CQA. Or in other words, each caffeine molecule seemingly has a minor CQA, most likely a di-CQA companion, which may be involved either in the complex or in the transport of caffeine to its location, or in both.
Much more pronounced is this process in the caffeine-free C. Are the di-CQAs in arabica and robusta protected from degradation because they form with caffeine and by the help of the two caffeoyl residues a stable, sandwich-like complex?
The half-caffeine laurina with a normal 5-CQA Carelli et al. Thus, the sensational discovery of the caffeine-free arabica mutant Silvarolla et al. Abrir menu Brasil. Brazilian Journal of Plant Physiology. Abrir menu. Plant Physiol. Thomas W. Baumann About the author. Hong, G. Biosynthesis of catechin components is differentially regulated in dark-treated tea Camellia sinensis L. Xiong, L. Dynamic changes in catechin levels and catechin biosynthesis-related gene expression in albino tea plants Camellia sinensis L.
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All authors reviewed the manuscript. Correspondence to Wen-Yan Han. Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Reprints and Permissions. Stimulation in primary and secondary metabolism by elevated carbon dioxide alters green tea quality in Camellia sinensis L. Sci Rep 7, Download citation.
Received : 07 November Accepted : 29 June Published : 11 August Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Plant Cell Reports By submitting a comment you agree to abide by our Terms and Community Guidelines.
If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Advanced search. Skip to main content Thank you for visiting nature. Download PDF. Subjects Climate-change ecology Ecophysiology Plant ecology Plant physiology. Abstract Rising CO 2 concentration, a driving force of climate change, is impacting global food security by affecting plant physiology.
Introduction Climate change is one of the most important complex factors that greatly impacts global food production. Results Exposure of tea seedlings to elevated CO 2 enhances plant growth and biomass accumulation Many experimental studies have shown that elevated CO 2 conditions stimulate plant growth and biomass production in a wide range of plant species 2 , 11 , 15 , Full size table. Figure 1. Full size image. Figure 2.
Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Discussion Rising atmospheric CO 2 concentrations have a profound effect on plant growth, development and responses to stresses 2 , 3 , 15 , Materials and Methods Plant material and growth conditions Seedlings of Longjing 43, a well-known green tea Camellia sisnensis L. Measurement of leaf respiration by O 2 uptake To determine leaf respiration, the O 2 uptake by leaf segments was measured using a Clark-type liquid-phase oxygen electrode Oxygraph-lab, Hansatech, UK Quantification of catechins, caffeine and individual amino acids The concentrations of caffeine and catechins in the extract was determined with a HPLC system Waters , Waters Corp.
Statistical analysis At least four independent replicates were conducted for each determination. References 1. Article Google Scholar 7. CAS Google Scholar 8. Article PubMed Google Scholar Article Google Scholar View author publications. Caffeine 1,3,7-trimethylxanthine is a plant secondary metabolite with a significant impact on multiple processes and regulatory pathways in the body.
Though major part of the population meets caffeine via coffee, tea or chocolate, it has also an important role in pharmacology and it is used as a supplementary substance in medicaments. Currently, the ability of caffeine to ameliorate some neurodegenerative disorders is proved in some studies.
This review describes basic data about caffeine including toxicity, pharmacokinetics, biological mechanism of the action, and metabolism.
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