We measured parameters related to canopy structure e. Evergreen species, though capable of fixing carbon throughout the year, often exhibit slow growth rates and low physiological activity. In recent years, expansion of native and exotic evergreen shrubs into forest understories has been documented worldwide. Potential mechanisms for expansion.

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Thus, the extent of the observable galactosylation reactions in any tissue preparation depends upon the molecular species of diacylglycerol and MGDG available in the preparation. The light intensity during growth of the plant appears to have little effect on galactolipid metabolism.

H 14j. Williams, M. Khan, and K. Siegenthaler and W. Eichenberger, eds. Elsevier, Amsterdam, Lem and P. Stumpf, Plant Physiol. Chlorophyll a and b are mixed prenyllipids: they possess an isoprenoid phytyl chain which is bound to a nonisoprenoid porphyfin ring system.

The possession of the phytyl side chain, which is esterified to the carboxyl group of the ring, gives the chlorophylls their lipid character. Because of their biogenetic relationship isopentenoid pathway , chlorophylls and carotenoids are also referred to as prenyl pigments. Tevini and H.

Lichtenthaler, eds. Springer-Verlag, Berlin and New York, All fights of reproduction in any form reserved. Introduction of hydroxy and epoxy functions into a-carotene ionone rings gives rise to lutein and lutein epoxide.

The carotenoids of green, photosynthetically active plant tissue, which are needed for photosynthetic function, are classified as primary carotenoids, whereas those of red fruits and flowers have been termed secondary carotenoids. Stoll, "Untersuchungen tiber Chlorophyll.

Seybold and K. Egle, Planta 26, Lichtenthaler, C. Buschmann, M. D, H. Fietz, T. Bach, U. Koze , and U. Rahmsdorf, Photosynth. Lichtenthaler, G. Kuhn, U. Prenzel, C. Buschmann, and D. Meier, Z. Strain, B. Cope, and W. Svec, this series, Vol. Watanabe, M. Kobayashi, A. Hongu, M. Nakazato, T. Hiyama, and N. Chemicalstructure of the main chloroplastcarotenoidsof higher plants. The xanthophylls antheraxanthin, luteinepoxid, and zeaxanthin are regular but minor carotenoid components.

Under highlight conditions the xanthophyll violaxanthin two epoxy, two hydroxy groups can by deepoxidized via antheraxanthin to zeaxanthin, the corresponding deepoxy derivative, which exhibits a chromatographic mobility similar to lutein. Though this xanthophyll cycle is well established, its 9 A. Hager, in "Pigments in Plants" F.

C, Czygan, ed. Fischer, Stuttgart, Tevini and K. Grumbach, Z. Lutein and neoxanthin apparently only function as accessory pigments in the photosynthetic light absorption, r-Carotene may partially serve as a light-absorbing pigment; its main function, however, seems to be the protection of chlorophyll a from photooxidation in or near the reaction center.

The main paths of biosynthesis of chlorophylls and carotenoids are established. Details concerning chlorophylls may be found in the reviews. Basic information on carotenoid biosynthesis can be found in Goodwin I and Davies. The aim of this chapter on chlorophylls and carotenoids is to give practical directions toward their quantitative isolation and determination in extracts from leaves, chloroplasts, thylakoid particles, and pigment proteins.

Hence the main emphasis is placed on the spectral characteristics and absorption coefficients of chlorophylls, pheophytins, and carotenoids, which are the basis for establishing equations to quantitatively determine them. Many data in this field were based on rather old observations and old instrumentation and needed revision. Therefore the specific absorption coefficients of the pigments were reevaluated and in part also first established for the purpose of this chapter.

This was achieved by using a two-beam spectrophotometer of the new generation, which allows programmed automatic recording and printing out of the proper wavelengths and absorbancy values.

Chlorophyll-Carotenoid Proteins Much of the present research work on photosynthetic pigments concerns isolation and characterization of pigment proteins. The main features of their isolation and pigment content will therefore be treated here. Schneider, Ber. Riidiger and J.

Benz, in "Chloroplast Biogenesis" R. Ellis, ed. Cambridge Univ. Press, London and New York, Goodwin, ed. Academic Press, New York, As compared to nm, absorbance of the light-harvesting proteins LHCPs increases at nm due to their high content in xanthophylls and chlorophyll b.

With respect to the free pigment zone FP , the scan at nm shows only the peak of free chlorophylls; this peak is broadened by the free carotenoids, when the scan is performed at nm. Except for violaxanthin, which to some extent is bound to the chloroplast envelope,15 all carotenoids and chlorophylls are bound to the thylakoids, the photochemically active photosynthetic biomembranes. Lichtenthaler, U.

Prenzel, R. Douce, and J. Joyard, Biochim. Acta , 99 Thornber, and R. After Lichtenthaler et al. The exact composition of the different pigment proteins has been established for Raphanus chloroplasts Table I.

Thornber, A n n u. Plant Physiol. Anderson, J. Waldron, and S. Machold, D. Simpson, and B. MOiler, Carlsberg Res. Bassi, O. Machold, and D. Simpson, Carlsberg Res. Argyroudi-Akoyunoglou and G. Burkard, G. Kuhn, and U. Prenzel, Z. Prenzel, and G. Kuhn, Z. Prenzel and H. Wintermans and P.


How does acetone extract chlorophyll?



[34] Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes







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