Hi all,
I was wondering if there are some works talking about the light absorption evolutionary strategies for phytoplankton cells. More precisely, if there are some proofs that the cells can change the light absorbed quantity due to some environmental stress?
Thank you in advance
Ilhem
Hello Ilhem,
Change in pigment concentration and type of pigment to impart a specific colour to the cell by reflecting and absorbing certain wavelength that suit specific needs in phytoplankton have been well documented. It is certainly an adaptation and cumulative adaptive features have always been proven a great impetus for any species to reorient their genetic makeup in order to be naturally suited to maximize their chances at utilizing certain or a broad spectrum scenario to their benefit. Their better suitability that had become their own nature through careful modifications is what we have come to understand as their evolution.
A very nice example of such a behaviour can be observed in a certain cyanobacteria and it's been currently investigated by Maria verdugo althöfer .
Hello Ilhem,
Change in pigment concentration and type of pigment to impart a specific colour to the cell by reflecting and absorbing certain wavelength that suit specific needs in phytoplankton have been well documented. It is certainly an adaptation and cumulative adaptive features have always been proven a great impetus for any species to reorient their genetic makeup in order to be naturally suited to maximize their chances at utilizing certain or a broad spectrum scenario to their benefit. Their better suitability that had become their own nature through careful modifications is what we have come to understand as their evolution.
A very nice example of such a behaviour can be observed in a certain cyanobacteria and it's been currently investigated by Maria verdugo althöfer .
Hi, First I would like to thank you for your replies and very interesting pistes; So if I captured you well, the cells can change the mechanism of the absorption related to the environment changes as a photoadaptation. Actually, I want to get more information (ref) about the possibility to change the self-shading proprieties. Means that in a restricted environment the cells can modify the self-shading to let the lower cells get access to light ... I don't know if something like that was already proved.
Thank you
Ilhem
Clearly, algae can change the light absorbed quantity in responce of environmental changes.
In general, shade-adapted algae synthesise more auxillary pigments, chl b, c (or f), or phycobilines, to trap more light that poorly absorbed by chl-a. As light intensity increased, photoprotective pigments a synthesised, e.g. scytonemin or extra small carotenoid-protein complexes in cyanobacteria. Tuning of photosynthesis in responce of light spectrum is also possible ( e.g. long-wavelength chl-a complexes in some algae, or chl-f or -d, or phycobilisome composition tuning).
Different algae seems to responce differently. As a rule, green algae and cyanobacteria initially regulate LHC/RC complex synthesis, resulting in the change of chl a/b or chl/pbs ratio. It seems that diatoms regulated primarily the PSI/PSII ratio, with small initial change of pigment ratios. At least that's what I read.
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