The Chla Chlb conversion probably needs some conversion and replacement time, maybe more than a day. Some details considered here:

Article Conversion of chlorophyll b to chlorophyll a precedes magnes...

I guess , it s not possible to change hours and minutes, there is a change about molecular level for responsible genes but directly Chla Chlb data will not change. I agree with Andy Pereira .

Best regards.

Thank you Andy and Ibrahim.

What about Chl dismantling? Anyone has any data?

Stay green mutants suggest genetic mechanisms for Chl dismantling:

Article Dismantling of Arabidopsis thaliana mesophyll cell chloropla...

The paper deals with chloroplast dismantling, but what about the chlorophyll? Anyone?

https://www.cell.com/trends/plant-science/fulltext/S1360-1385(09)00049-1

Genes like staygreen and pathway could be involved

Thank you very much Andy. Stay-green mutants are good models and senescence is also a good opportunity to study Ch dismantling. However, I am looking for the data on Chl changes in non-senescing leaves, especially when environmental changes (temperature or and/ illumination) occur.

Dear Renata, @Renata Baczek-Kwinta

You should be more specific when explaining your question. First thing to know (so somebody can give you a smart answer) is to know what kind of photosynthetic organism are you interested in (trees, tropical vegetation, bushes, algae, cyanobacteria, lichens). Second, what is the spatio-temporal ROI for your specific question, and finally, to complete your question, you should be more specific about what conditions should be involved in inducing fast/long changes in Chl/carotenoids within minutes/hours/days.

Under specific conditions, Chl/Car content may change, however, here the experimental limiting factor for observing those pigment variatons is the method to determine Chl/Car content because of the statistical dispersion obtained with most of common used protocols (typically solvent extraction and spectrometric determination).

It is well known that both plants and algae exhibit circadian rhythms. Pigment modulation during diurnal cycles can be traced with photoreceptor systems, in vivo, in situ. SeeArticle Diurnal Variation in Pigment Content in Porphyra laciniata a...

I have observed diurnal changes in Chl and car content in Chlorella vulgaris cultivars growing in outside tubular photo-reactors with controlled nutrient solution conditions. We measured Chl fluorescence (both modulated and direct technique), pigments content, Oxygen and CO2 exchange, flow speed, etc. We could induce mineral deficiencies (typically Fe, Mn, Mg, K, Ca and N and observe the deficiency effects in biomass, carotenoid and chlorophyll content. The precise mechanism is not well known. There is still debate around the possible biochemical pathways for modulated Chl content.

Hundreds of papers providing data can be obtained with google Scholar.

Hope this can help

Ronald

Fully agree with this. Seen and documented with diatoms. Definitely "hours" ...

@ Ronald Maldonado Rodriguez Dear Ronald, I already know that Google Scholar and other scientific databases have gathered huge amounts of papers dealing with the topic :) However, many of them report alterations recorded in large time intervals, but those on fast changes in Chls are based on laboratory models. To be more specific - OK, I am interested in land plants mostly, but if anyone has a good report on any photosynthesising organism, I would appreciate. A researcher should avoid narrowing in literature research. @ Stephen Greer - any proof? Thank you in advance.

Look up any microalgal paper regarding light cycling or formation of lipids, especially recent ones.... If I gave you too much "proof" I might have to "get Putin" on ya....this type of stuff stays out of the "published" realm because of the crossover it has with biofuel research. Needless to say, the microalgal candidate literature (patents and journals) is full of proof and insinuation of the transition of fast photosynthesizing cells (full of chlorophyll) to senescent cells (full of TGs and lipids) in hours --I've done it in less than 8. Do a search on "lipid trigger" to get you started down the rabbit hole :)

Hello Renata, Renata Baczek-Kwinta ,

yes, Scholar is the best way to narrow your search for research papers.

Anyway, as I told you before, the limiting factor for doing such kind of research work is time as it takes a long while for doing Chl extraction and determination of Chl a / b + Car content. It is a time consuming procedure and any minor changes in experimental conditions will produce important statistical variation. If you are lucky, your boss will be no so rigid about taking "enough" samples for doing the statistical validation procedure...

My best advise: get a commercial digital portable Chlorophyll-meter, a Konica Minolta SPAD508, or an Optiscience's CCM200plus, or a french Dualex or a british CL01 manufactured by Hansatech UK. All of them provide readings very fast, within less than a couple of minutes or so.... beside that, they are relatively not so expensive (I've got mine from e-bay (or Amazon?), a decent enough second hand chinese manufactured machine, for less than 400 bucks). OK, with that little nice gadget you could play and see by yourself what's going on with your "land plants". You could even test them directly in the lab, under controlled conditions... induce changes and see immediately the effect on pigment content as compared to a control group.

Sincerely, that's the best way to go ahead. If you cannot buy it, maybe you could borrow it from another lab or from Prof. Hazem Kalaji, he is official commercial representative and distributor of many types of plant physiology machines in Warsaw and he is teaching at the Life Sciences' Warsaw University. Hazem is a great teacher and a brilliant scientist.

Please, have a look at his paper about comparing 4 different tradename chlorophyllmeters:

https://www.tandfonline.com/doi/abs/10.1080/01904167.2016.1263323?journalCode=lpla20

Also, there is a new chlorophyllmeter called atleaf CHLPlus. Never tested it, but read about it, people seem quite happy with it. Have a look at https://www.atleaf.com/

regards,

Ronald

@Ronald Thank you very much, I know the Warsaw group papers and I have the devices you mention and often use them. I am also aware that their readings depend not only on the Chl pool, but also on the leaf structure (thickness, spongy/palisade mesophyll, intracellular spaces :Article Photosynthetic activity of variegated leaves of Coleus × hyb...

Renata Baczek-Kwinta Renata, it has been demonstrated that plants adopt strategies (at different levels of organisation) to cope with light and temperature stress. Your specific question is: Could an increase in temperature and PPFD be associated to changes in pigment content? In the literature we find plenty of references about the role of Xanthophylls and Zeoxanthin cycles during photoinhibition. In such cases, pigment changes have been reported to occur within minutes to hours after onset of light/temperature stress. Temperature may play a synergistic effect to cope with light stress. During millions of years of evolution, plants developed very sophisticated mechanisms to cope with direct sun light or its lack. Imagine yourself, taking a sun bath a full day or two, no sun cream, nothing. Just you under the sun... the result: red skin, general severe burnt even, terribly painful... Now look at those trees in the garden around... Those leaves in these trees, and the whole tree actually, is exposed to sun light not just for one day but for a whole season... months of sun... every year. So, yes, for sure, they regulate thickness, etc, but also chloroplast orientation, even they manage to regulate full leaf orientation. My best guess is that you could repeat the experiment, under lab controlled conditions. measuring every hour, from 06h00 o'clock, increasing illumination with a potentiometer, to a max level around 13h00, and decreasing it until it becomes dark, at about 19h00. You can simulate sunflecks too. If the species of interest are not easy to move inside a lab, then, let Mahoma go to the mountain. Don't forget to tell him to bring the machines with him.

The main point with repeating the experiment in the lab is to check Chlorophyll a/b + carotenoids content by extraction and spectrometry, and compare it with readings using the CL-01 chlorophyllmeter, just to be sure there is no a conformation effect, screening effect, chloroplast orientation effect and so many other tpes of effect that may fool the optical measurements with your CL-01. Do not forget to measure a control group, same plant species, same soil/ground, same soil humidity, good ventilation/aeration, keep a "normal" canopy temperature, the only difference has to be light and temperature.

We just started spring. Soon will be summer. Enough time for growing some plants in the greenhouse to play with them and plenty of time for preparing for a field mesuring campaign in nature. You can test it in any species that typically grow exposed to full sun. The species that better adapt to any conditions and have a full arsenal of evolutional strategies to cope with many types of severe stresses are invasive species. Have a look for them too ;-)

Regards,

Ronald

Dear @Ronald, my specific question is: Could an increase in temperature and PPFD be associated to changes in CHLOROPHYLL content?

And my general question as follows: I am looking for scientific data concerning alterations in chlorophyll content, Chla/b and Chl/Car. How fast such changes can be in nature? Can they occur in hours, minutes?

I am aware about VAZ cycle, I am not interested in Cars themselves, I am interested in Chls. I know that sping had come, and despite my own study I am looking for the literature data. IF ANYONE HAS/KNOWS A SPECIFIC SOURCE OF THE DATA (a book, a paper, a dataset), I am interested.

Right, ok Renata Baczek-Kwinta, Renata, here, some references, found here:

Article Silicon-induced increase in chlorophyll is modulated by the ...

0) http://www.plantphysiol.org/content/159/1/433

it is about chl b modulation, very interesting paper

1) O.N. Silva, A.K.S. Lobato, F.W. Ávila, R.C.L. Costa, C.F. Oliveira Neto,B.G. Santos Filho, A.P. Martins Filho, R.P. Lemos, J.M. Pinho, M.B.C.L. Medeiros, M.S. Cardoso,

I.P. Andrade (2012) Silicon-induced increase in chlorophyll is modulated by the leaf water potential in two water-deficient tomato cultivars. Plant Soil Environ., 58 (11): 481-486

2) Silicon application resulted in an increase of chlorophyll and an improvement in the antioxi-dant system in Lycopersicon esculentum plants that were exposed to salt stress, but the regulatory mechanism responsible for this effect was not explained (Al-aghabary et al. 2004).

Al-aghabary K., Zhu Z., Shi Q. (2004): Influence of silicon supply on chlorophyll content, chlorophyll fluorescence, and anti-oxidant enzyme activities in tomato plants under salt stress. Journal of Plant Nutrition, 27: 2101–2115

3) Ávila et al. (2010) investigated the interaction between silicon and nitrogen and reported an increase in the levels of chlorophyll a in Oryza sativa plants.

Ávila F.W., Baliza D.P., Faquin V., Araujo J., Ramos S.J. (2010): Silicon-nitrogen interaction in rice cultivated under nutrient solution. Revista Ciencia Agronomica, 41: 184–190.

4) Drought typically causes a significant decrease in photosynthetic pigments. However, there is limited information regarding the effects of silicon on chlorophyll levels in water-deficient plants

5) Gandul-Rojas B., Roca M., Mínguez-Mosquera M.I. (2004): Chlorophyll and carotenoid degradation mediated by thylakoid-associated peroxidative activity in olives (Olea europaea) c v. Hojiblanca. Journal of Plant Physiology, 161: 499–507

6) Oliveira Neto C.F., Lobato A.K.S., Gonçalves-Vidigal M.C., Costa R.C.L., Santos Filho B.G., Alves G.A.R., Maia W.J.M.S., Cruz F.J.R., Neves H.K.B., Lopes M.J.S. (2009): Carbon compounds and chlorophyll contents in sorghum submitted to water deficit during three growth stages. Journal of Food, Agriculture and Environment, 7: 588–593

7) Article Ecophysiological Responses of Calcicole Cyclobalanopsis glau...

8) This paper, in section 2.1 touch your topic too

https://academic.oup.com/jxb/article/65/15/4065/597575

Hope this may help you with your research,

Ronald

Ronald Maldonado Rodriguez Thank you very much, I know some of them, some will analyse. Best regards,

Renata

Dear Renata

I think the presence of chlorophyll in any plant due to the interaction of environmental conditions with genetic makeup of any plant

The tall plant protects the short plant from high temperatures through intercropping which indicates the formation of plant pigments will be affected under these conditions

Chlorophyll, the pigment responsible for the characteristic green colour of several fruit and vegetables, can degrade to undesirable grey-brown compounds such as pheophorbide and pheophytin. This degradation is mediated by acid and the enzyme chlorophyllase. An increase in incident light beyond a particular point causes the breakdown of chlorophyll and hence decreases the rate of photosynthesis. The amount of chlorophyll also affects the rate of photosynthesis: plants in lighting conditions unfavourable for photosynthesis may synthesise more chlorophyll, to absorb the light required. Amount of chlorophyll in leaf tissue is influenced by nutrient availability and environmental stresses such as drought, salinity, cold and heat etc. Therefore, it has been of special interest to plant scientists to quantify chlorophyll contents in leaves. Leaf chlorophyll is a key indicator of leaf greenness, and it is often used to investigate leaf nutrient deficiencies and changes in chlorophyll. Canopy chlorophyll content is also an indicator of seasonal carbon uptake in forest ecosystems.