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Another question about photosynthesis
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Paul Ciszek
Jun 18, 2013, 1:49:53 AM6/18/13
to
Cyanobacteria, and by extension green plants, make use of the red and blue
ends of the spectrum while discarding the middle. (Hence the popularity
of garish red & blue LED lighting in the latest, most high-tech forms of
hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
Do they use these pigments to capture and make use of green or yellow light
from the middle of the spectrum?
--
Please reply to: |"We establish no religion in this country, we command
pciszek at panix dot com | no worship, we mandate no belief, nor will we ever.
Autoreply is disabled | Church and state are, and must remain, separate."
| --Ronald Reagan, October 26, 1984
ends of the spectrum while discarding the middle. (Hence the popularity
of garish red & blue LED lighting in the latest, most high-tech forms of
hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
Do they use these pigments to capture and make use of green or yellow light
from the middle of the spectrum?
--
Please reply to: |"We establish no religion in this country, we command
pciszek at panix dot com | no worship, we mandate no belief, nor will we ever.
Autoreply is disabled | Church and state are, and must remain, separate."
| --Ronald Reagan, October 26, 1984
alias Ernest Major
Jun 18, 2013, 3:34:11 AM6/18/13
to
On 18/06/2013 06:49, Paul Ciszek wrote:
> Cyanobacteria, and by extension green plants, make use of the red and blue
> ends of the spectrum while discarding the middle. (Hence the popularity
> of garish red & blue LED lighting in the latest, most high-tech forms of
> hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
> Do they use these pigments to capture and make use of green or yellow light
> from the middle of the spectrum?
>
Wikipedia says so ...
> Cyanobacteria, and by extension green plants, make use of the red and blue
> ends of the spectrum while discarding the middle. (Hence the popularity
> of garish red & blue LED lighting in the latest, most high-tech forms of
> hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
> Do they use these pigments to capture and make use of green or yellow light
> from the middle of the spectrum?
>
http://en.wikipedia.org/wiki/Accessory_pigment
.... but this article isn't well referenced (but Wikipedia tends to be
down on primary sources, and I guess most of the literature on the acual
chemistry is to be found in primary sources).
--
alias Ernest Major
rnorman
Jun 18, 2013, 5:34:28 AM6/18/13
to
rather than a real computer.
My impression is that the accessory pigments somehow channel the
electron excitation from the captured photons into the same
photosystem but I don't know just how it is done and it is too
tedious for me to look it up on my phone. I also don't know why
chlorophyll should ignore the most energetic part of the solar
radiation.
However I happen now to be floating down the Volga River in the
company of a plant physiologist so I will try to find out.
marc.t...@wanadoo.fr
Jun 18, 2013, 7:19:48 AM6/18/13
to
On Jun 18, 7:49 am, nos...@nospam.com (Paul Ciszek) wrote:
> Cyanobacteria, and by extension green plants, make use of the red and blue
> ends of the spectrum while discarding the middle. (Hence the popularity
> of garish red & blue LED lighting in the latest, most high-tech forms of
> hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
> Do they use these pigments to capture and make use of green or yellow light
> from the middle of the spectrum?
I recommend you to read the 2010 paper by Robert E. Blankenship:
> Cyanobacteria, and by extension green plants, make use of the red and blue
> ends of the spectrum while discarding the middle. (Hence the popularity
> of garish red & blue LED lighting in the latest, most high-tech forms of
> hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
> Do they use these pigments to capture and make use of green or yellow light
> from the middle of the spectrum?
Blankenship RE (2010) Early Evolution of Photosynthesis. Plant
Physiol. 154:434-438
In particular this author specified the following:
"The RC (Reaction Center) complex is at the heart of photosynthesis;
so much attention has been paid to understand the evolution of RCs. A
wealth of evidence, including structural,
spectroscopic, thermodynamic, and molecular sequence analysis, clearly
segregates all known RCs into two types of complexes, called type I
and type II. Anoxygenic phototrophs have just one type, either type I
or II, while all oxygenic phototrophs have one of each type. The
distribution of RC types on the tree of life is shown in Figure 1 and
a comparative electron transport diagram that compares the different
RCs in different types of organisms is shown in Figure 2, with type I
RCs color coded green and type II RCs color coded purple".
marc.t...@wanadoo.fr
Jun 18, 2013, 9:09:30 AM6/18/13
to
"Photosynthetic cyanobacteria have chlorophyll a and carotenoids in
addition to some unusual accessory pigments named phycobilins. The
blue pigment, phycocyanin and the red one, phycoerythrin, absorb
wavelengths of light for photosynthesis that are missed by chlorophyll
and the carotenoids" from Kenneth Todar at the following link:
http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad=rja&ved=0CDQQFjAA&url=http%3A%2F%2Ftextbookofbacteriology.net%2Fprocaryotes_3.html&ei=SVvAUbicEcOIhQexvYHACw&usg=AFQjCNEpomO6YDY_EMYfUNjBP_pO7EdxPQ&sig2=SISUBK-cBMXvtMmvGhNa3A
rnorman
Jun 18, 2013, 12:59:18 PM6/18/13
to
On Tue, 18 Jun 2013 06:09:30 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
wavelengths of light missed by chlorophyll a. The question is the
mechanism by which electron excitation can be passed to photosystems
I and II in order to produce the reducing power needed to fix
(reduce) carbon to carbohydrate. My colleague would be happy to
explain the actions of all sorts of plant hormones and phytochromes
but the biophysics of electron excitation is somewhat specialized.
Note: accessory pigments have other functions. They also protect
plants from photorespiration that interferes with photosynthesis. Of
course horticulturists use artificial selection to produce plants
with unusually colored and patterned foliage because of these
pigments.
wrote:
> On Jun 18, 11:34ï¿œam, rnorman <r_s_nor...@comcast.net> wrote:
> > On Tue, 18 Jun 2013 08:34:11 +0100, alias Ernest Major
> > <{$t...@meden.demon.co.ukl> wrote:
> > > On 18/06/2013 06:49, Paul Ciszek wrote:
> > > > Cyanobacteria, and by extension green plants, make use of the
red
> > and blue
> > > > ends of the spectrum while discarding the middle. ￜ(Hence the
> > On Tue, 18 Jun 2013 08:34:11 +0100, alias Ernest Major
> > <{$t...@meden.demon.co.ukl> wrote:
> > > On 18/06/2013 06:49, Paul Ciszek wrote:
> > > > Cyanobacteria, and by extension green plants, make use of the
red
> > and blue
> > popularity
> > > > of garish red & blue LED lighting in the latest, most
high-tech
> > forms of
> > > > hydroponics.) ï¿œNow, some algae contain other pigments, such as
> > > > of garish red & blue LED lighting in the latest, most
high-tech
> > forms of
> > rhodophyta.
> > > > Do they use these pigments to capture and make use of green or
> > yellow light
> > > > from the middle of the spectrum?
> > > Wikipedia says so ...
> > > ￜ ￜhttp://en.wikipedia.org/wiki/Accessory_pigment
> > > > Do they use these pigments to capture and make use of green or
> > yellow light
> > > > from the middle of the spectrum?
> > > Wikipedia says so ...
> > > .... but this article isn't well referenced (but Wikipedia
tends to
> > be
> > > down on primary sources, and I guess most of the literature on
the
> > acual
> > > chemistry is to be found in primary sources).
> > Sorry about the formatting but I am responding from a smart phone
> > rather than a real computer.
> > My impression is that the accessory pigments somehow channel the
> > electron excitation from the captured photons into the same
> > photosystem but I don't know just how it is done and it is too
> > tedious for me to look it up on my phone. ï¿œI also don't know why
tends to
> > be
> > > down on primary sources, and I guess most of the literature on
the
> > acual
> > > chemistry is to be found in primary sources).
> > Sorry about the formatting but I am responding from a smart phone
> > rather than a real computer.
> > My impression is that the accessory pigments somehow channel the
> > electron excitation from the captured photons into the same
> > photosystem but I don't know just how it is done and it is too
> > chlorophyll should ignore the most energetic part of the solar
> > radiation.
> > However I happen now to be floating down the Volga River in the
> > company of a plant physiologist so I will try to find out.
> I found the following assertion:
> "Photosynthetic cyanobacteria have chlorophyll a and carotenoids in
> addition to some unusual accessory pigments named phycobilins. The
> blue pigment, phycocyanin and the red one, phycoerythrin, absorb
> wavelengths of light for photosynthesis that are missed by
chlorophyll
> and the carotenoids" from Kenneth Todar at the following link:
>
http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad
=rja&ved=0CDQQFjAA&url=http%3A%2F%2Ftextbookofbacteriology.net%2Fprocar
yotes_3.html&ei=SVvAUbicEcOIhQexvYHACw&usg=AFQjCNEpomO6YDY_EMYfUNjBP_pO
7EdxPQ&sig2=SISUBK-cBMXvtMmvGhNa3A
Sorry, I assumed it was obvious that the accessory pigments absorb
> > radiation.
> > However I happen now to be floating down the Volga River in the
> > company of a plant physiologist so I will try to find out.
> I found the following assertion:
> "Photosynthetic cyanobacteria have chlorophyll a and carotenoids in
> addition to some unusual accessory pigments named phycobilins. The
> blue pigment, phycocyanin and the red one, phycoerythrin, absorb
> wavelengths of light for photosynthesis that are missed by
chlorophyll
> and the carotenoids" from Kenneth Todar at the following link:
>
http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad
=rja&ved=0CDQQFjAA&url=http%3A%2F%2Ftextbookofbacteriology.net%2Fprocar
yotes_3.html&ei=SVvAUbicEcOIhQexvYHACw&usg=AFQjCNEpomO6YDY_EMYfUNjBP_pO
7EdxPQ&sig2=SISUBK-cBMXvtMmvGhNa3A
wavelengths of light missed by chlorophyll a. The question is the
mechanism by which electron excitation can be passed to photosystems
I and II in order to produce the reducing power needed to fix
(reduce) carbon to carbohydrate. My colleague would be happy to
explain the actions of all sorts of plant hormones and phytochromes
but the biophysics of electron excitation is somewhat specialized.
Note: accessory pigments have other functions. They also protect
plants from photorespiration that interferes with photosynthesis. Of
course horticulturists use artificial selection to produce plants
with unusually colored and patterned foliage because of these
pigments.
Paul Ciszek
Jun 18, 2013, 4:23:13 PM6/18/13
to
In article <almarsoft.4608...@news.eternal-september.org>,
rnorman <r_s_n...@comcast.net> wrote:
>
>My impression is that the accessory pigments somehow channel the
>electron excitation from the captured photons into the same
>photosystem but I don't know just how it is done and it is too
>tedious for me to look it up on my phone. I also don't know why
>chlorophyll should ignore the most energetic part of the solar
>radiation.
Well, one theory about that is that cyanobacteria were late to the
>
>My impression is that the accessory pigments somehow channel the
>electron excitation from the captured photons into the same
>photosystem but I don't know just how it is done and it is too
>tedious for me to look it up on my phone. I also don't know why
>chlorophyll should ignore the most energetic part of the solar
>radiation.
game, and purple bacteria of some sort (that absorbed the abundant
green and yellow, leaving only red and blue) were already hogging
all the sunlight for a form of photosynthesis that did not release
oxygen or fix carbon, just captured energy for the bacteria to use.
(Maybe I shouldn't call it photosythesis?) Anyway, cyanobacteria
evolved to make use of the left over blue and red light; it just so
happened that their form of photosynthesis released oxygen, which
the other form of light-feeding bacteria could not tolerate. Purple
photosynthetic bacteria still survive today, but they have to avoid
oxygen.
>However I happen now to be floating down the Volga River in the
>company of a plant physiologist so I will try to find out.
Paul J Gans
Jun 18, 2013, 4:31:32 PM6/18/13
to
Paul Ciszek <nos...@nospam.com> wrote:
>Cyanobacteria, and by extension green plants, make use of the red and blue
>ends of the spectrum while discarding the middle. (Hence the popularity
>of garish red & blue LED lighting in the latest, most high-tech forms of
>hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
>Do they use these pigments to capture and make use of green or yellow light
>from the middle of the spectrum?
I've often wondered about similar things. Sunlight is
>Cyanobacteria, and by extension green plants, make use of the red and blue
>ends of the spectrum while discarding the middle. (Hence the popularity
>of garish red & blue LED lighting in the latest, most high-tech forms of
>hydroponics.) Now, some algae contain other pigments, such as rhodophyta.
>Do they use these pigments to capture and make use of green or yellow light
>from the middle of the spectrum?
most strong in the green. One might expect that energy
to be used.
--
--- Paul J. Gans
Paul J Gans
Jun 18, 2013, 5:27:09 PM6/18/13
to
rnorman <r_s_n...@comcast.net> wrote:
>On Tue, 18 Jun 2013 06:09:30 -0700 (PDT), marc.t...@wanadoo.fr
>wrote:
>On Tue, 18 Jun 2013 06:09:30 -0700 (PDT), marc.t...@wanadoo.fr
>wrote:
>> On Jun 18, 11:34?am, rnorman <r_s_nor...@comcast.net> wrote:
>> > On Tue, 18 Jun 2013 08:34:11 +0100, alias Ernest Major
>> > <{$t...@meden.demon.co.ukl> wrote:
>> > > On 18/06/2013 06:49, Paul Ciszek wrote:
>> > > > Cyanobacteria, and by extension green plants, make use of the
>red
>> > and blue
>> > > > ends of the spectrum while discarding the middle. ?(Hence the
>> > On Tue, 18 Jun 2013 08:34:11 +0100, alias Ernest Major
>> > <{$t...@meden.demon.co.ukl> wrote:
>> > > On 18/06/2013 06:49, Paul Ciszek wrote:
>> > > > Cyanobacteria, and by extension green plants, make use of the
>red
>> > and blue
>> > popularity
>> > > > of garish red & blue LED lighting in the latest, most
>high-tech
>> > forms of
>> > > > hydroponics.) ?Now, some algae contain other pigments, such as
>> > > > of garish red & blue LED lighting in the latest, most
>high-tech
>> > forms of
>> > rhodophyta.
>> > > > Do they use these pigments to capture and make use of green or
>> > yellow light
>> > > > from the middle of the spectrum?
>> > > Wikipedia says so ...
>> > > ? ?http://en.wikipedia.org/wiki/Accessory_pigment
>> > > > Do they use these pigments to capture and make use of green or
>> > yellow light
>> > > > from the middle of the spectrum?
>> > > Wikipedia says so ...
>> > > .... but this article isn't well referenced (but Wikipedia
>tends to
>> > be
>> > > down on primary sources, and I guess most of the literature on
>the
>> > acual
>> > > chemistry is to be found in primary sources).
>> > Sorry about the formatting but I am responding from a smart phone
>> > rather than a real computer.
>> > My impression is that the accessory pigments somehow channel the
>> > electron excitation from the captured photons into the same
>> > photosystem but I don't know just how it is done and it is too
>> > tedious for me to look it up on my phone. ?I also don't know why
>tends to
>> > be
>> > > down on primary sources, and I guess most of the literature on
>the
>> > acual
>> > > chemistry is to be found in primary sources).
>> > Sorry about the formatting but I am responding from a smart phone
>> > rather than a real computer.
>> > My impression is that the accessory pigments somehow channel the
>> > electron excitation from the captured photons into the same
>> > photosystem but I don't know just how it is done and it is too
>> > chlorophyll should ignore the most energetic part of the solar
>> > radiation.
>> > However I happen now to be floating down the Volga River in the
>> > company of a plant physiologist so I will try to find out.
>> I found the following assertion:
>> "Photosynthetic cyanobacteria have chlorophyll a and carotenoids in
>> addition to some unusual accessory pigments named phycobilins. The
>> blue pigment, phycocyanin and the red one, phycoerythrin, absorb
>> wavelengths of light for photosynthesis that are missed by
>chlorophyll
>> and the carotenoids" from Kenneth Todar at the following link:
>>
>http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad
>=rja&ved=0CDQQFjAA&url=http%3A%2F%2Ftextbookofbacteriology.net%2Fprocar
>yotes_3.html&ei=SVvAUbicEcOIhQexvYHACw&usg=AFQjCNEpomO6YDY_EMYfUNjBP_pO
>7EdxPQ&sig2=SISUBK-cBMXvtMmvGhNa3A
>Sorry, I assumed it was obvious that the accessory pigments absorb
>wavelengths of light missed by chlorophyll a. The question is the
>mechanism by which electron excitation can be passed to photosystems
>I and II in order to produce the reducing power needed to fix
>(reduce) carbon to carbohydrate. My colleague would be happy to
>explain the actions of all sorts of plant hormones and phytochromes
>but the biophysics of electron excitation is somewhat specialized.
I have, in my time, attended more than one seminar on
>> > radiation.
>> > However I happen now to be floating down the Volga River in the
>> > company of a plant physiologist so I will try to find out.
>> I found the following assertion:
>> "Photosynthetic cyanobacteria have chlorophyll a and carotenoids in
>> addition to some unusual accessory pigments named phycobilins. The
>> blue pigment, phycocyanin and the red one, phycoerythrin, absorb
>> wavelengths of light for photosynthesis that are missed by
>chlorophyll
>> and the carotenoids" from Kenneth Todar at the following link:
>>
>http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad
>=rja&ved=0CDQQFjAA&url=http%3A%2F%2Ftextbookofbacteriology.net%2Fprocar
>yotes_3.html&ei=SVvAUbicEcOIhQexvYHACw&usg=AFQjCNEpomO6YDY_EMYfUNjBP_pO
>7EdxPQ&sig2=SISUBK-cBMXvtMmvGhNa3A
>Sorry, I assumed it was obvious that the accessory pigments absorb
>wavelengths of light missed by chlorophyll a. The question is the
>mechanism by which electron excitation can be passed to photosystems
>I and II in order to produce the reducing power needed to fix
>(reduce) carbon to carbohydrate. My colleague would be happy to
>explain the actions of all sorts of plant hormones and phytochromes
>but the biophysics of electron excitation is somewhat specialized.
electron excitation and transfer in photosynthesis.
Sadly, I recall none of the details except that the process
involves compounds easily excited by a photon that leaves
an electron excited. Then this electron is transferred
either down the chain to an appropriate site, or transferred
to another molecule entirely. Eventually the electron,
energy degraded but not to zero, ends up at a site where the
"action" takes place.
I know that's a tremendously uninformative paragraph, but
I can't do any better. The takeaway for me which I still
remember is that I now understood why photosynthesis is
so inefficient.
>Note: accessory pigments have other functions. They also protect
>plants from photorespiration that interferes with photosynthesis. Of
>course horticulturists use artificial selection to produce plants
>with unusually colored and patterned foliage because of these
>pigments.
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