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The plots look sane, but they're unreferenced so I intend to redo with a documented set of published numbers. I have numbers for a and b; does anyone know of nice clean series for the c or d floating around on the net? iMeowbot~ Mw 23:42, 13 Feb 2005 (UTC)
Hey, everyone, isn't the absorbance spectra of chlorophyll wrong? It shows an absorbance peak for chlorophyll b at 470nm, but I can't find any source to back that up. Where does this data come from? Fephisto ( talk) 14:14, 4 October 2021 (UTC)
How do I know if any articles have been redirected to Chlorophyll? I would like to know other names for Chlorophyll so I am able to share this information with a Facebook Group. Thank you, -- Wyn.junior ( talk) 17:47, 12 June 2019 (UTC)
The structure shown for Chlorophyll f is mirror imaged and slightly rotated from all the other structures (and also shows the terminating C and H atoms left out in the other images). It would be useful to draw this with the same conventions as the other variants, since it's actually more similar than a casual look would make it appear. Skepticalgiraffe ( talk) 20:09, 12 February 2020 (UTC)
@ Smokefoot and Skepticalgiraffe: Done! -- Slashme ( talk) 20:39, 16 February 2020 (UTC)
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Chlorophyll does not efficiently absorb green light but this does not mean that it reflects green. It transmits green light. The misconception that chlorophyll would specifically reflect green light comes from school teaching. My extensive search in scientific literature did not provide any experimental evidence supporting the idea of reflection of green light by chlorophyll - but I would be utterly interested in seeing a reference in which chlorophyll is shown to reflect light. In my laboratory, I work a lot with thylakoid membrane preparations and plant extracts that contain chlorophylls a and b as the main pigments, and both become very dark green or almost black when they are highly concentrated. On black background, both tend to disappear. If chlorophyll reflected green light, they would make a green spot on black surface.
In the lack of earlier research I conducted, in my research group, an experimental study. We measured reflectance from green leaves and from similar leaves devoid of chlorophyll. In all cases, green reflectance of white or yellow leaves was higher than that of green leaves. The paper has now been published online in a peer-reviewed journal (Virtanen et al., Journal of Biological Education, https://doi.org/10.1080/00219266.2020.1858930). The results reveal the obvious: leaves are green because chlorophyll absorbs red and blue but does not block the green light reflected from the tissues, mostly from the cell walls.
I understand that Wikipedia should reflect the consensus, and one paper against a large body of contrasting evidence might only be mentioned as a discrepant voice, if even so. However, in this case, the consensus is not, at least in the light of my database searches, based on science. Therefore I feel that my argument should be taken seriously. Besides, the evidence in the Virtanen et al. paper is absolutely conclusive. I tried to edit the Wikipedia page in 2019 because I thought that this is a simple mistake and a real no-brainer. The edit was reverted because I could not cite any reference (and I think that was quite right). However, now that I have the reference, my edit on December 29, 2020, became reverted without any notice, and the reference was omitted.
The question whether chlorophyll reflects or transmits green light is not only of academic interest. For remote sensing of chlorophyll content, it is important to understand how the green color of plant leaves is formed. Similarly, some plant biological applications are based on reflectance measurements. It may also be important for school children to understand the differences between artists' colors that function like chlorophyll (only absorb - e.g. marker pens, some crayons) and colors that contain reflective stuff and therefore both absorb and reflect (some crayons, in fact also many watercolors). The video published as an attachment of the Virtanen et al. paper touches this point (and also shows that on a black paper, colors that only absorb but do not reflect, including green chlorophyll-containing acetonic extract of plant leaves, do not produce any image while light-reflecting crayons can be used to draw on black paper).
EsaTyystjärvi ( talk) 16:05, 2 January 2021 (UTC)
spread potentially false rumours. Either one believes the science in your article (which I do) or one refutes it but can't be said to be a rumour! Subject to further comments by other editors who may read this Talk Page, I'll add back something along the lines that you did, as I certainly have no WP:COI. Mike Turnbull ( talk) 17:42, 2 January 2021 (UTC)
Thank you - I am sorry that I did not pay attention to the abbreviations and did not try to find out what they mean. I agree that a citation to my own paper might raise a conflict of interest. However, I am concerned about the fact that the opposite view does not need any reference to scientific literature. The finding that chlorophyll does not reflect light is certainly not breaking news in the plant biology community! Otherwise I would have chosen a photosynthesis journal rather than an educational one :) EsaTyystjärvi ( talk) 08:31, 3 January 2021 (UTC)
[had] difficulty in understanding the statement that chlorophyll does not efficiently absorb green light. There is no need to alter the current text in the article, which is already accurate. However, if you wish to propose some alternative text you believe would improve the article, please specify it here, perhaps in the form of an WP:EDITREQUEST so that a WP:CONSENSUS for your change can be sought. Mike Turnbull ( talk) 11:23, 29 July 2022 (UTC)
I said perhaps in the form of an WP:EDITREQUEST
, not that you couldn't be
WP:BOLD if you wished,
Phacelias. However, I would point out that my edit that you have taken issue with was made in January 2021. This article has 286 page watchers and 39 editors who have made recent edits (according to
the page information). So you are likely to be in a minority in seeing that edit as problematic. Also, please note that
EsaTyystjärvi is male.
Mike Turnbull (
talk)
13:25, 29 July 2022 (UTC)
![]() | This ![]() It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||||||||||||||||||
|
![]() | This article was the
MCB Collaboration of the Month for the month of February 2008. For more details, see the
MCB Collaboration of the Month history. |
This page has archives. Sections older than 90 days may be automatically archived by Lowercase sigmabot III when more than 5 sections are present. |
The plots look sane, but they're unreferenced so I intend to redo with a documented set of published numbers. I have numbers for a and b; does anyone know of nice clean series for the c or d floating around on the net? iMeowbot~ Mw 23:42, 13 Feb 2005 (UTC)
Hey, everyone, isn't the absorbance spectra of chlorophyll wrong? It shows an absorbance peak for chlorophyll b at 470nm, but I can't find any source to back that up. Where does this data come from? Fephisto ( talk) 14:14, 4 October 2021 (UTC)
How do I know if any articles have been redirected to Chlorophyll? I would like to know other names for Chlorophyll so I am able to share this information with a Facebook Group. Thank you, -- Wyn.junior ( talk) 17:47, 12 June 2019 (UTC)
The structure shown for Chlorophyll f is mirror imaged and slightly rotated from all the other structures (and also shows the terminating C and H atoms left out in the other images). It would be useful to draw this with the same conventions as the other variants, since it's actually more similar than a casual look would make it appear. Skepticalgiraffe ( talk) 20:09, 12 February 2020 (UTC)
@ Smokefoot and Skepticalgiraffe: Done! -- Slashme ( talk) 20:39, 16 February 2020 (UTC)
![]() | This
edit request has been answered. Set the |answered= or |ans= parameter to no to reactivate your request. |
{{subst:trim|1=
Chlorophyll does not efficiently absorb green light but this does not mean that it reflects green. It transmits green light. The misconception that chlorophyll would specifically reflect green light comes from school teaching. My extensive search in scientific literature did not provide any experimental evidence supporting the idea of reflection of green light by chlorophyll - but I would be utterly interested in seeing a reference in which chlorophyll is shown to reflect light. In my laboratory, I work a lot with thylakoid membrane preparations and plant extracts that contain chlorophylls a and b as the main pigments, and both become very dark green or almost black when they are highly concentrated. On black background, both tend to disappear. If chlorophyll reflected green light, they would make a green spot on black surface.
In the lack of earlier research I conducted, in my research group, an experimental study. We measured reflectance from green leaves and from similar leaves devoid of chlorophyll. In all cases, green reflectance of white or yellow leaves was higher than that of green leaves. The paper has now been published online in a peer-reviewed journal (Virtanen et al., Journal of Biological Education, https://doi.org/10.1080/00219266.2020.1858930). The results reveal the obvious: leaves are green because chlorophyll absorbs red and blue but does not block the green light reflected from the tissues, mostly from the cell walls.
I understand that Wikipedia should reflect the consensus, and one paper against a large body of contrasting evidence might only be mentioned as a discrepant voice, if even so. However, in this case, the consensus is not, at least in the light of my database searches, based on science. Therefore I feel that my argument should be taken seriously. Besides, the evidence in the Virtanen et al. paper is absolutely conclusive. I tried to edit the Wikipedia page in 2019 because I thought that this is a simple mistake and a real no-brainer. The edit was reverted because I could not cite any reference (and I think that was quite right). However, now that I have the reference, my edit on December 29, 2020, became reverted without any notice, and the reference was omitted.
The question whether chlorophyll reflects or transmits green light is not only of academic interest. For remote sensing of chlorophyll content, it is important to understand how the green color of plant leaves is formed. Similarly, some plant biological applications are based on reflectance measurements. It may also be important for school children to understand the differences between artists' colors that function like chlorophyll (only absorb - e.g. marker pens, some crayons) and colors that contain reflective stuff and therefore both absorb and reflect (some crayons, in fact also many watercolors). The video published as an attachment of the Virtanen et al. paper touches this point (and also shows that on a black paper, colors that only absorb but do not reflect, including green chlorophyll-containing acetonic extract of plant leaves, do not produce any image while light-reflecting crayons can be used to draw on black paper).
EsaTyystjärvi ( talk) 16:05, 2 January 2021 (UTC)
spread potentially false rumours. Either one believes the science in your article (which I do) or one refutes it but can't be said to be a rumour! Subject to further comments by other editors who may read this Talk Page, I'll add back something along the lines that you did, as I certainly have no WP:COI. Mike Turnbull ( talk) 17:42, 2 January 2021 (UTC)
Thank you - I am sorry that I did not pay attention to the abbreviations and did not try to find out what they mean. I agree that a citation to my own paper might raise a conflict of interest. However, I am concerned about the fact that the opposite view does not need any reference to scientific literature. The finding that chlorophyll does not reflect light is certainly not breaking news in the plant biology community! Otherwise I would have chosen a photosynthesis journal rather than an educational one :) EsaTyystjärvi ( talk) 08:31, 3 January 2021 (UTC)
[had] difficulty in understanding the statement that chlorophyll does not efficiently absorb green light. There is no need to alter the current text in the article, which is already accurate. However, if you wish to propose some alternative text you believe would improve the article, please specify it here, perhaps in the form of an WP:EDITREQUEST so that a WP:CONSENSUS for your change can be sought. Mike Turnbull ( talk) 11:23, 29 July 2022 (UTC)
I said perhaps in the form of an WP:EDITREQUEST
, not that you couldn't be
WP:BOLD if you wished,
Phacelias. However, I would point out that my edit that you have taken issue with was made in January 2021. This article has 286 page watchers and 39 editors who have made recent edits (according to
the page information). So you are likely to be in a minority in seeing that edit as problematic. Also, please note that
EsaTyystjärvi is male.
Mike Turnbull (
talk)
13:25, 29 July 2022 (UTC)