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57

Good question. If you look at the spectral energy distribution in the accepted answer here, we see that photons with wavelengths less than ~300 nm are absorbed by species such as ozone. Much beyond 750 infrared radiation is largely absorbed by species such as water and carbon dioxide. Therefore the vast majority of solar photons reaching the surface have ...


41

Surely it would be even more beneficial for plants to be black instead of red or green, from an energy absorption point of view. And Solar cells are indeed pretty dark. But, as Rory indicated, higher energy photons will only produce heat. This is because the chemical reactions powered by photosynthesis require only a certain amount of energy, and any ...


22

The vast majority of a tree's carbon comes from the air, which averages 0.03-0.04% by volume (300-400 ppmv) CO2. This is fixed through photosynthesis and eventually stored as glucose which the plant can then use for its metabolism. Doing some quick math, this means that in order to produce 1 kilogram of carbohydrates (e.g. cellulose) a plant needs to ...


20

I believe it is because of a trade off between absorbing a wide range of photons and not absorbing too much heat. Certainly this is a reason why leaves are not black - the enzymes in photosynthesis as it stands would be denatured by the excess heat that would be gained. This may go some of the way towards explaining why green is reflected rather than red ...


18

The phosphate group in NADPH doesn't affect the redox abilities of the molecule, it is too far away from the part of the molecule involved in the electron transfer. What the phosphate group does is to allow enzymes to discriminate between NADH and NADPH, which allows the cell to regulate both independently. The ratio of NAD+ to NADH inside the cell is high, ...


16

There are quite a few questions and thoughts in there, I'll try to cover them all: First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons). You are correct to assume the C is further used for the growing process; it is used to make sugars which ...


13

There are several key ways in which rising atmospheric CO₂ concentrations will affect photosynthesis, and these are related to the different types of photosynthesis. In order to properly answer your question, I'll provide some background about photosynthesis itself. Photosynthesis evolved in a high-CO₂ atmosphere, before the oxygen-enrichment of the ...


13

There are 5 answers, all "yes". First: there exists at least one animal which can produce its own chlorophyll: A green sea slug appears to be part animal, part plant. It's the first critter discovered to produce the plant pigment chlorophyll. The sea slugs live in salt marshes in New England and Canada. In addition to burglarizing the genes needed ...


11

There is quite a fun article here which discusses the colours of hypothetical plants on planets around other stars. Stars are classified by their spectral type which is dictated by their surface temperatures. The Sun's is relatively hot, and it's spectral energy distribution peaks in the green region of the spectrum. However the majority of stars in the ...


11

I wanted to add a little more to the excellent answer above, especially since the OP asks about research into this question in a "real-world context". There is a substantial body of evidence on exactly this question that comes from experiments at "Free Air CO2 Enrichment" (FACE) sites. FACE is an experimental method/technology in which standing ecosystems ...


11

I'm surprised nobody has mentioned Jan van Helmont. To summarise Blankenship's account, in the 17th century, he (Helmont, not Blankenship) grew a tree in a known dry weight of soil and weighed the fallen leaves of the tree, and then eventually the whole tree including the root system. He found that the mass of the soil had barely diminished and concluded ...


11

I'll stick to considering the atmospheric composition, as referred to in the original question: Although there may be some rare exceptions that I can't recall, under normal circumstances all green plants use aerobic respiration with O2 as final electron acceptor for energy production. This means that they require oxygen, which is essentially absent from the ...


10

Photosynthetic pigments are the chemicals which take part in photosynthesis, in particular they are they ones which absorb photons and fluoresce (emit photons of a different wavelength) or emit electrons. Pigments are molecules, and chlorophyll is a key example. These pigments are required for photosynthesis to take place, as they generate the electrons ...


8

There are many different kinds of plants that have independently evolved this sort of variegation (non-green areas) in the leaves. However, the mechanisms by which they effect this vary between species. Some have little or no chlorophyll in the non-green areas, but many others have changed the architecture of their leaf cell layers in the non-green areas, ...


8

The selection you refer in multiple species could be due to a mutual advantage. If fruits absorb visible wavelengths, they can be spotted by other animals and eaten together with the seeds. Seeds can then mature inside the host and, once eliminated with the feces, grow up a new plant in a different place. This is not only valid for light absorption, but for ...


7

If you mean the efficiency at which plants convert light energy to chemical energy (in sugar or other reduced C compounds) then there is definitely variability between plants, both at the species and individual level. The photosynthetic efficiency WP page gives ranges of between 0.1 and 8% of total solar radiation converted to "biomass", but these values are ...


6

According to wikipedia, plants typically convert around 5% of the energy of the sunlight that hit the leaves into energy usable by the plant. Sugarcane seems to be the best, it converts up to 8% of the energy into actual biomass. The best solar panels on the market, according to the Independent, convert 21% of energy from sunlight into usable electricity. ...


6

During the daylight, the plant is photosynthesising faster than it is respiring so there is no net uptake of oxygen (the oxygen of course being produced in the as part of the photosynthesis). Of course, this only applies for tissues where photosynthesis is occurring. In the roots of the plant, oxygen must always be present in the surrounding soil/growth ...


6

This is an interesting topic! Crassulacean acid metabolism is a second CO₂ fixation pathway where CO₂ is absorbed at night. The CO₂ is fixed into maleic acid HOOC-CH₂CH(OH)-COOH which stores some of the CO₂ in the form of carboxyl groups. During the day carboxylases release the CO₂ for fixation during the day. This is an adaptation where the stomata ...


6

Shigeta submitted his answer as I was writing this! Sanseveria is one of a wide group of plants (mainly succulents) that adopt a photosynthetic strategy referred to as crassulacean acid metabolism (CAM). Recall the basics of photosynthesis. The light-dependent reactions use energy from captured photons to generate ATP and NADPH, with the generation of O2. ...


6

Disclaimer: photosynthesis is not my field of expertise. I assume you are asking about the amount of light needed for photosynthesis to take place, not the light intensity needed to sustain the plant? Since photosynthesis is an interaction between chlorophyll and single photons I would assume that photosynthetic reactions could take place with just single ...


5

There are two factors at play here. First is the balance between how much energy a plant can collect and how much it can use. It is not a problem of too much heat, but too many electrons. If it were a question of heat, a number of flowers selected for their black pigmentation would have their petals cooked off. ;) If a plant does not have enough water, is ...


5

The green pigment is indeed chlorophyll, and the fruits do perform photosynthesis. It's not just "fruiting" plants that do this either. Some shading experiments i saw estimated that up to 30% of the sugars assimilated into the barley ears (basically the grain) can come from photosynthesis occurring in those organs.


5

It matters a lot. Take a look at this graph: This graph is for the "normal" plants containing chlorophyll. There're also "abnormal" :-) ones, simple water plants and cyanobacteria, that contain various phycobilins for photosynthesis instead of the chlorophyll. If your question is practical, I'd recommend using specialy-designed fluorescent lamps called ...


5

This is not my field by a long shot, so take what I say with a grain of salt. However, this question is very hard to answer because whether or not a plant will grow depends on a great variety of factors. Even if we ignore the temperature as you say, there are other considerations. These include, but are not limited to: Soil composition, I doubt that ...


5

You haven't directed us to any evidence for your assertion, so it is difficult to evaluate. I'm not a plant physiologist, so I will argue from first principles: photosynthesis consumes CO2 and produces O2: 6CO2 +6H2O -> C6H12O6 + 6O2 respiration consumes O2 and produces CO2: C6H12O6 + 6O2 -> 6CO2 +6H2O Plants do both of these things at the same ...


5

Chlorophyll can use a quite broad range of light for photosynthesis, the only range where it is not working is approximately between 500 and 620nm. See this adsorption spectrum of chlorophyll (from the Wikipedia article on Chlorophyll): The lack of chlorophyll to absorb light between 500 and 620nm (roughly) results in the green color of leafs, because ...


4

Sure! Trees get most of their carbon from CO2 via photosynthesis, which is converted to glucose and then to other organic compounds.


4

Your latter assumption is the best we have so far, to my understanding. Here are a few excerpts from "Early Evolution of Photosynthesis" published in Plant Physiology, October 2010 (emphasis mine): There is suggestive evidence that photosynthetic organisms were present approximately 3.2 to 3.5 billion years ago... Overwhelming evidence indicates ...



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