CHLOROPHYLL (also CHLOROPHYL) is any of several closely related green
pigments found in cyanobacteria and the chloroplasts of algae and
plants . Its name is derived from the Greek words χλωρός,
_chloros_ ("green") and φύλλον, _phyllon_ ("leaf"). Chlorophyll
is essential in photosynthesis , allowing plants to absorb energy from
Chlorophyll absorbs light most strongly in the blue portion of the
electromagnetic spectrum , followed by the red portion. Conversely,
it is a poor absorber of green and near-green portions of the
spectrum, which it reflects, producing the green color of
Chlorophyll molecules are specifically
arranged in and around photosystems that are embedded in the thylakoid
membranes of chloroplasts. Two types of chlorophyll exist in the
photosystems of green plants: chlorophyll a and b.
Chlorophyll was first isolated and named by Joseph Bienaimé Caventou
Pierre Joseph Pelletier in 1817.
* 2 Chemical structure
* 3 Measurement of chlorophyll content
* 4 Biosynthesis
* 5 Complementary light absorbance of anthocyanins with chlorophylls
* 6 Distribution
* 7 Culinary use
* 8 See also
* 9 References
Absorption maxima of chlorophylls against the spectrum of white
Chlorophyll absorbs energy from light strongly at visible
Chlorophyll is vital for photosynthesis , which allows plants to
absorb energy from light .
Chlorophyll molecules are specifically arranged in and around
photosystems that are embedded in the thylakoid membranes of
chloroplasts . In these complexes, chlorophyll serves two primary
functions. The function of the vast majority of chlorophyll (up to
several hundred molecules per photosystem) is to absorb light and
transfer that light energy by resonance energy transfer to a specific
chlorophyll pair in the reaction center of the photosystems. The two
currently accepted photosystem units are photosystem II and
photosystem I , which have their own distinct reaction centres, named
P700 , respectively. These centres are named after the
wavelength (in nanometers ) of their red-peak absorption maximum. The
identity, function and spectral properties of the types of chlorophyll
in each photosystem are distinct and determined by each other and the
protein structure surrounding them. Once extracted from the protein
into a solvent (such as acetone or methanol ), these chlorophyll
pigments can be separated into chlorophyll a and chlorophyll b .
The function of the reaction center of chlorophyll is to absorb light
energy and transfer it to other parts of the photosystem. The absorbed
energy of the photon is transferred to an electron in a process called
charge separation. The removal of the electron from the chlorophyll is
an oxidation reaction. The chlorophyll donates the high energy
electron to a series of molecular intermediates called an electron
transport chain . The charged reaction center of chlorophyll (P680+)
is then reduced back to its ground state by accepting an electron
stripped from water. The electron that reduces P680+ ultimately comes
from the oxidation of water into O2 and H+ through several
intermediates. This reaction is how photosynthetic organisms such as
plants produce O2 gas, and is the source for practically all the O2 in
Photosystem I typically works in series with
Photosystem II; thus the P700+ of
Photosystem I is usually reduced as
it accepts the electron, via many intermediates in the thylakoid
membrane, by electrons coming, ultimately, from
Electron transfer reactions in the thylakoid membranes are complex,
however, and the source of electrons used to reduce P700+ can vary.
The electron flow produced by the reaction center chlorophyll
pigments is used to pump H+ ions across the thylakoid membrane,
setting up a chemiosmotic potential used mainly in the production of
ATP (stored chemical energy) or to reduce NADP+ to
NADPH is a
universal agent used to reduce CO2 into sugars as well as other
Reaction center chlorophyll–protein complexes are capable of
directly absorbing light and performing charge separation events
without the assistance of other chlorophyll pigments, but the
probability of that happening under a given light intensity is small.
Thus, the other chlorophylls in the photosystem and antenna pigment
proteins all cooperatively absorb and funnel light energy to the
reaction center. Besides chlorophyll _a_, there are other pigments,
called accessory pigments , which occur in these pigment–protein
_ Space-filling model of the chlorophyll a_ molecule
Chlorophyll is a chlorin pigment, which is structurally similar to
and produced through the same metabolic pathway as other porphyrin
pigments such as heme . At the center of the chlorin ring is a
magnesium ion . This was discovered in 1906, and was the first time
that magnesium had been detected in living tissue. For the structures
depicted in this article, some of the ligands attached to the Mg2+
center are omitted for clarity. The chlorin ring can have several
different side chains, usually including a long phytol chain. There
are a few different forms that occur naturally, but the most widely
distributed form in terrestrial plants is chlorophyll _a_. After
initial work done by German chemist
Richard Willstätter spanning from
1905 to 1915, the general structure of chlorophyll _a_ was elucidated
Hans Fischer in 1940. By 1960, when most of the stereochemistry of
chlorophyll _a_ was known,
Robert Burns Woodward published a total
synthesis of the molecule. In 1967, the last remaining
stereochemical elucidation was completed by Ian Fleming , and in 1990
Woodward and co-authors published an updated synthesis.
was announced to be present in cyanobacteria and other oxygenic
microorganisms that form stromatolites in 2010; a molecular formula
of C55H70O6N4Mg and a structure of (2-formyl )-chlorophyll _a_ were
deduced based on NMR, optical and mass spectra. The different
structures of chlorophyll are summarized below:
_ Structure of chlorophyll a_
_ Structure of chlorophyll b_
_ Structure of chlorophyll d_
_ Structure of chlorophyll c1_
_ Structure of chlorophyll c2_
_ Structure of chlorophyll f_
When leaves degreen in the process of plant senescence , chlorophyll
is converted to a group of colourless tetrapyrroles known as
NONFLUORESCENT CHLOROPHYLL CATABOLITES (NCC's) with the general
These compounds have also been identified in several ripening fruits.
MEASUREMENT OF CHLOROPHYLL CONTENT
Absorbance spectra of free chlorophyll a_ (blue) and _b_ (red)
in a solvent. The spectra of chlorophyll molecules are slightly
modified _in vivo_ depending on specific pigment-protein interactions.
Because it absorbs red and blue light strongly but is
transparent to green light, pure chlorophyll has a strong green
Measurement of the absorption of light is complicated by the solvent
used to extract the chlorophyll from plant material, which affects the
* In diethyl ether , chlorophyll _a_ has approximate absorbance
maxima of 430 nm and 662 nm, while chlorophyll _b_ has approximate
maxima of 453 nm and 642 nm.
* The absorption peaks of chlorophyll _a_ are at 665 nm and 465 nm.
Chlorophyll _a_ fluoresces at 673 nm (maximum) and 726 nm. The peak
molar absorption coefficient of chlorophyll _a_ exceeds 105 M−1
cm−1, which is among the highest for small-molecule organic
* In 90% acetone-water, the peak absorption wavelengths of
chlorophyll _a_ are 430 nm and 664 nm; peaks for chlorophyll _b_ are
460 nm and 647 nm; peaks for chlorophyll _c1_ are 442 nm and 630 nm;
peaks for chlorophyll _c2_ are 444 nm and 630 nm; peaks for
chlorophyll _d_ are 401 nm, 455 nm and 696 nm.
By measuring the absorption of light in the red and far red regions,
it is possible to estimate the concentration of chlorophyll within a
Ratio fluorescence emission can be used to measure chlorophyll
content. By exciting chlorophyll “a” fluorescence at a lower
wavelength, the ratio of chlorophyll fluorescence emission at 705 nm
+/- 10 nm and 735 nm +/-10 nm can provide a linear relationship of
chlorophyll content when compared to chemical testing. The ratio
F735/F700 provided a correlation value of r2 0.96 compared to chemical
testing in the range from 41 mg m−2 up to 675 mg m−2. Gitelson
also developed a formula for direct readout of chlorophyll content in
mg m−2. The formula provided a reliable method of measuring
chlorophyll content from 41 mg m−2 up to 675 mg m−2 with a
correlation r2 value of 0.95.
In plants, chlorophyll may be synthesized from succinyl-CoA and
glycine , although the immediate precursor to chlorophyll _a_ and _b_
is protochlorophyllide . In
Angiosperm plants, the last step, the
conversion of protochlorophyllide to chlorophyll, is light-dependent
and such plants are pale (etiolated ) if grown in darkness.
Non-vascular plants and green algae have an additional
light-independent enzyme and grow green even in darkness.
Chlorophyll itself is bound to proteins and can transfer the absorbed
energy in the required direction.
Protochlorophyllide occurs mostly in
the free form and, under light conditions, acts as a photosensitizer ,
forming highly toxic free radicals . Hence, plants need an efficient
mechanism of regulating the amount of chlorophyll precursor. In
angiosperms, this is done at the step of aminolevulinic acid (ALA),
one of the intermediate compounds in the biosynthesis pathway. Plants
that are fed by ALA accumulate high and toxic levels of
protochlorophyllide; so do the mutants with the damaged regulatory
system. Further information:
Chlorosis is a condition in which leaves produce insufficient
chlorophyll, turning them yellow.
Chlorosis can be caused by a
nutrient deficiency of iron —called iron chlorosis—or by a
shortage of magnesium or nitrogen . Soil pH sometimes plays a role in
nutrient-caused chlorosis; many plants are adapted to grow in soils
with specific pH levels and their ability to absorb nutrients from the
soil can be dependent on this.
Chlorosis can also be caused by
pathogens including viruses, bacteria and fungal infections, or
COMPLEMENTARY LIGHT ABSORBANCE OF ANTHOCYANINS WITH CHLOROPHYLLS
Superposition of spectra of chlorophyll a and b with oenin
(malvidin 3O glucoside), a typical anthocyanidin , showing that, while
chlorophylls absorb in the blue and yellow/red parts of the visible
spectrum, oenin absorbs mainly in the green part of the spectrum,
where chlorophylls don't absorb at all.
Anthocyanins are other plant pigments . The absorbance pattern
responsible for the red color of anthocyanins may be complementary to
that of green chlorophyll in photosynthetically active tissues such as
Quercus coccifera _ leaves. It may protect the leaves from
attacks by plant eaters that may be attracted by green color.
Play media Animation depicting nearly four years worth of
SeaWiFS ocean chlorophyll concentration.
The chlorophyll maps show milligrams of chlorophyll per cubic meter
of seawater each month. Places where chlorophyll amounts were very
low, indicating very low numbers of phytoplankton , are blue. Places
where chlorophyll concentrations were high, meaning many phytoplankton
were growing, are yellow. The observations come from the Moderate
Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite.
Land is dark gray, and places where MODIS could not collect data
because of sea ice, polar darkness, or clouds are light gray.The
highest chlorophyll concentrations, where tiny surface-dwelling ocean
plants are thriving , are in cold polar waters or in places where
ocean currents bring cold water to the surface, such as around the
equator and along the shores of continents. It is not the cold water
itself that stimulates the phytoplankton. Instead, the cool
temperatures are often a sign that the water has welled up to the
surface from deeper in the ocean, carrying nutrients that have built
up over time. In polar waters, nutrients accumulate in surface waters
during the dark winter months when plants cannot grow. When sunlight
returns in the spring and summer, the plants flourish in high
Chlorophyll is registered as a food additive (colorant), and its E
number is E140. Chefs use chlorophyll to color a variety of foods and
beverages green, such as pasta and absinthe .
Chlorophyll is not
soluble in water, and it is first mixed with a small quantity of
vegetable oil to obtain the desired solution .
Wikimedia Commons has media related to CHLOROPHYLL _.
Bacteriochlorophyll , related compounds in phototrophic bacteria
Chlorophyll a , an essential chlorophyll pigment
Chlorophyll b , also an essential chlorophyll pigment
Chlorophyllin , a semi-synthetic derivative of chlorophyll
Deep chlorophyll maximum
Grow light , a lamp that promotes photosynthesis
Chlorophyll fluorescence , to measure plant stress
* ^ May, Paul. "Chlorophyll".
University of Bristol
University of Bristol .
* ^ "chlorophyll".
Online Etymology Dictionary .
* ^ Muneer, Sowbiya; Kim, Eun Jeong; Park, Jeong Suk; Lee, Jeong
Hyun (2014-03-17). "Influence of Green,
Red and Blue
Diodes on Multiprotein Complex Proteins and Photosynthetic Activity
Light Intensities in Lettuce Leaves (Lactuca sativa
L.)". _International Journal of Molecular Sciences_. 15 (3):
4657–4670. ISSN 1422-0067 . PMC 975419 _. PMID 24642884 . doi
* ^ Speer, Brian R. (1997). "Photosynthetic Pigments". UCMP
University of California Museum of Paleontology .
* ^ See:
* Delépine, Marcel (September 1951). "Joseph Pelletier and Joseph
Journal of Chemical Education _. 28 (9): 454. Bibcode
:1951JChEd..28..454D. doi :10.1021/ed028p454 .
* Pelletier and Caventou (1817) "Notice sur la matière verte des
feuilles" (Notice on the green material in leaves), _Journal de
Pharmacie_, 3 : 486-491. On p. 490, the authors propose a new name for
chlorophyll. From p. 490: _"Nous n'avons aucun droit pour nommer une
substance connue depuis long-temps, et à l'histoire de laquelle nous
n'avons ajouté que quelques faits ; cependant nous proposerons, sans
y mettre aucune importance, le nom de_ chlorophyle_, de_ chloros_,
couleur, et_ φυλλον_, feuille : ce nom indiquerait le rôle
qu'elle joue dans la nature."_ (We have no right to name a substance
known for a long time, and to whose story we have added only a few
facts ; however, we will propose, without giving it any importance,
the name _chlorophyll_, from _chloros_, color, and _φυλλον_,
leaf : this name would indicate the role that it plays in nature.)
* ^ Carter, J. Stein (1996). "Photosynthesis". University of
Cincinnati . Archived from the original on 2013-06-29.
* ^ Nature (July 5, 2013). "Unit 1.3. Photosynthetic Cells".
_Essentials of Cell Biology_. nature.com.
* ^ Marker, A. F. H. (1972). "The use of acetone and methanol in
the estimation of chlorophyll in the presence of phaeophytin".
_Freshwater Biology_. 2 (4): 361–385. doi
* ^ Jeffrey, S. W.; Shibata, Kazuo (February 1969). "Some Spectral
Chlorophyll c from Tridacna crocea Zooxanthellae".
Biological Bulletin _.
Marine Biological Laboratory . 136 (1):
JSTOR 1539668 . doi :10.2307/1539668 .
* ^ Gilpin, Linda (21 March 2001). "Methods for analysis of benthic
photosynthetic pigment". School of Life Sciences,
Napier University .
Archived from the original on April 14, 2008. Retrieved 2010-07-17.
* ^ Willstätter, Richard (1906) "Zur Kenntniss der Zusammensetzung
des Chlorophylls" ( to the knowledge of the composition of
chlorophyll), _Annalen der Chemie_, 350 : 48-82. From p. 49: _"Das
Hauptproduct der alkalischen Hydrolyse bilden tiefgrüne Alkalisalze.
In ihnen liegen complexe Magnesiumverbindungen vor, die das Metall in
einer gegen Alkali auch bei hoher Temperatur merkwürdig
widerstandsfähigen Bindung enthalten."_ (Deep green alkali salts form
the main product of alkali hydrolysis. In them, complex magnesium
compounds are present, which contain the metal in a bond that's
extraordinarily resistant to alkali even at high temperature.)
* ^ _A_ _B_ Motilva, Maria-José (2008). "Chlorophylls – from
functionality in food to health relevance". _5th Pigments in Food
congress- for quality and health_ (Print). University of Helsinki.
ISBN 978-952-10-4846-3 .
* ^ Woodward, R. B.; Ayer, W. A.; Beaton, J. M.; Bickelhaupt, F.;
Bonnett, R.; Buchschacher, P.; Closs, G. L.; Dutler, H.; Hannah, J.;
et al. (July 1960). "The total synthesis of chlorophyll". _Journal of
the American Chemical Society _. 82 (14): 3800–3802. doi
* ^ Fleming, Ian (14 October 1967). "Absolute Configuration and the
Structure of Chlorophyll". _Nature _. 216 (5111): 151–152. Bibcode
:1967Natur.216..151F. doi :10.1038/216151a0 .
* ^ Woodward, R. B.; Ayer, William A.; Beaton, John M.;
Bickelhaupt, Friedrich; Bonnett, Raymond; Buchschacher, Paul; Closs,
Gerhard L.; Dutler, Hans; Hannah, John; et al. (1990). "The total
synthesis of chlorophyll a" (PDF). _Tetrahedron _. 46 (22):
7599–7659. doi :10.1016/0040-4020(90)80003-Z .
* ^ Jabr, Ferris (August 19, 2010) A New Form of Chlorophyll?.
_Scientific American_. Retrieved on 2012-04-15.
* ^ Infrared chlorophyll could boost solar cells. New Scientist.
August 19, 2010. Retrieved on 2012-04-15.
* ^ Chen, Min; Schliep, Martin; Willows, Robert D.; Cai, Zheng-Li;
Neilan, Brett A.; Scheer, Hugo (September 2010). "A Red-Shifted
Chlorophyll". _Science _. 329 (5997): 1318–1319. Bibcode
:2010Sci...329.1318C. PMID 20724585 . doi :10.1126/science.1191127 .
* ^ Müller, Thomas; Ulrich, Markus; Ongania, Karl-Hans; Kräutler,
Bernhard (2007). "Colorless Tetrapyrrolic
Found in Ripening
Fruit Are Effective Antioxidants" . _Angewandte
Chemie _. 46 (45): 8699–8702. PMC 2912502 _. PMID 17943948 . doi
* ^ Gross, Jeana (1991). Pigments in vegetables: chlorophylls and
carotenoids_. Van Nostrand Reinhold, ISBN 0442006578 .
* ^ Porra, R. J. (1989). "Determination of accurate extinction
coefficients and simultaneous equations for assaying chlorophylls a
and b extracted with four different solvents: verification of the
concentration of chlorophyll standards by atomic absorption
spectroscopy". _Biochimica et Biophysica Acta (BBA) - Bioenergetics_.
Volume 975 (3): 384, 394. doi :10.1016/S0005-2728(89)80347-0 – via
Elsevier Science Direct.
* ^ Larkum, edited by Anthony W. D. Larkum, Susan E. Douglas & John
A. Raven (2003). _
Photosynthesis in algae_. London: Kluwer. ISBN
0-7923-6333-7 . CS1 maint: Extra text: authors list (link )
* ^ Cate, Thomas; Perkins, T. D. (September 2003). "Joseph
Pelletier and Joseph Caventou". _Journal of
Tree Physiology_. 23 (15):
1077–1079. doi :10.1093/treephys/23.15.1077 .
* ^ Gitelson A. A., Buschmann C., Lichtenthaler H. K. (1999) “The
Fluorescence Ratio F735/F700 as an Accurate Measure of
Chlorophyll Content in Plants” Remote Sens. Enviro. 69:296-302
* ^ Meskauskiene R; Nater M; Goslings D; Kessler F; op den Camp R;
Apel K. (23 October 2001). "FLU: A negative regulator of chlorophyll
biosynthesis in Arabidopsis thaliana" . _Proceedings of the National
Academy of Sciences _. 98 (22): 12826–12831. Bibcode
JSTOR 3056990 . PMC 60138 _. PMID 11606728 .
doi :10.1073/pnas.221252798 .
* ^ Duble, Richard L. "Iron
Chlorosis in Turfgrass". Texas A&M
University . Retrieved 2010-07-17.
* ^ Karageorgou, P.; Manetas, Y. (2006). "The importance of being
red when young: Anthocyanins and the protection of young leaves of
Quercus coccifera from insect herbivory and excess light". Tree
Physiology_. 26 (5): 613–21. PMID 16452075 . doi
Chlorophyll : Global Maps. Earthobservatory.nasa.gov. Retrieved
* ^ Adams, Jad (2004). _Hideous absinthe : a history of the devil
in a bottle_. United Kingdom: I.B.Tauris, 2004. p. 22. ISBN 1860649203
History of botany
* Non-vascular plants
* Vascular plants
* Storage organs
Hypanthium (Floral cup)
* Bulk flow
PLANT GROWTH AND HABIT
* Woody plants
* Herbaceous plants
* Succulent plants
Alternation of generations
Alternation of generations
* Evolutionary development
* Evolutionary history
History of plant systematics
* Correct name
* Author citation
* International Code of Nomenclature for algae, fungi, and plants
* - for Cultivated Plants (ICNCP)
* International Association for
Plant Taxonomy (IAPT)
Plant taxonomy systems
Cultivated plant taxonomy
Cultivated plant taxonomy