101

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 ...


87

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 ...


46

tl;dr: Yes, all plants breathe.— I'm not sure whether I understand the question correctly; because all plants use respiration! Some of the organic high-energy substances produced by photosynthesis are later "burnt" to produce energy in the same "respiration" process used by animals, producing CO2. The difference to animals is that green plants ...


42

Chlorophyll absorbs photons (light). The energy in the photon extracts an electron from a molecule of water. Electron transfer creates intermediate superoxide and hydroxyl radicals from the oxygen and hydrogen from the donor water molecule. In normal photosynthesis, these radicals are quickly used to power the reduction of NADP to NADPH and the synthesis ...


39

71% of the earth's surface is taken up by water. Not surprisingly therefore, the seas are an important source of oxygen. National Geographic claims that photosynthesis by phytoplankton (mostly single-celled phototrophs, such as cyanobacteria, green algae and diatoms) account for half of the earth's oxygen production. The other half, they claim, is produced ...


35

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, ...


34

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 ...


34

There are 5 answers, all "yes" (though the first one is disputable). 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 ...


30

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 ...


28

Short answer It has been shown that plants may already suffer from doubling the atmospheric CO2 concentration from 340 to 610 ppm, something that might happen during the next hundred years or so based on current emissions. Background A popular science website tells us that an excess of carbon dioxide (CO2) reduces the rate of transpiration of some plants. ...


21

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 ...


21

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 ...


20

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 ...


20

Photosynthesis is nearly all visible light. There's usually not enough UV and thermodynamics more or less rules out infrared. Chris covered that pretty spectacularly, but that nearly is significant. There is some evidence that certain kinds of fungi can use gamma rays or other ionizing radiation for energy, but they're not particularly common. Melanin is ...


20

The issue is that it is not always a cycle, when you drain wetlands or burn forests to make more farmland that's not a cycle that is permanent change. A change that can continue having effects for centuries. Then of course you have petroleum fuel used to run tractors and the production of fertilizer which are often not cycles either but pure extraction. ...


17

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 ...


17

Photosynthesis only occurs in the visible light.have a look at the absorption spectra of the different pigments involved in photosynthesis, you see that all these pigments absorb light between 400 and 700nm (from a diagram from here): You see that the absorption spectra of chlorophyll a and b are located from 400 to 500nm and again from 630 to 700nm. The ...


17

Of course they can and do, except in total darkness (spectroscopically, only bands in the far red and in the blue spectra matter - blanking these affects 'total darkness'). In photosynhesis a photon is adsorbed by Photosystem II to break down water into oxygen and protons in solution. Another photon must be adsorbed by Photosystem ! to power the enzymatic ...


16

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 ...


16

It depends upon the plant species. As explained in Algae thrive under Pure CO2 Nature 227, pages 744–745 (15 August 1970): Cyanidium caldarium (an algae found in Yellowstone National Park) grows much better in pure carbon dioxide than in air. However, other plants can suffer from acidification of cell fluids at high carbon dioxide concentrations. ...


16

Most of ornamental (often variegated ) plants do performs photosynthesis. They do have chlorophyll even if their color is not green. They have non-green color due to various different pigments. These extra color has their own functions like blocking harsh sunlight or protection from insects (Karageorgou and Manetas 2006). In many non-green plants ...


15

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 ...


15

Besides the unicellular organisms cited by other answers (and the fact that plants actually do respiration), there are some animals who are able to get, although indirectly, energy from photosynthesis through symbiosis with photosynthesizing organisms. You can try the spotted salamander Ambystoma maculatum: The spotted salamander is similar to the sea-...


15

Short Answer: Any plant can produce oxygen at night, but plants cannot produce oxygen without light. Longer Answer: It all comes down to spontaneity of a reaction i.e. whether a reaction can occur without input of energy or not. Before we talk about spontaneity, I feel it better to first know about the process we're talking about here. In photosynthesis, ...


14

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 ...


14

You are missing some knowledge here for sure, photosynthesis is a little complicated at A level, so I will describe it in brief. During photosynthesis electrons and protons (A hydrogen atom without the electron) are required for a process called the electron transport chain and proton motive force. This happens during the light dependent stage of ...


14

Photosynthesis uses chlorophyll (or other pigments) for harnessing photons and water (or other compounds) as electron donor $H_2O = 1/2O_2 + 2H^+ + 2e^-$. After splitting the water it sends the electrons through the further steps of an electron transport chain and at the end it reduces $NADP^+$ into $NADPH$. Meanwhile it increases the $H^+$ concentration ...


13

Yes. In fact the organic compounds' mass comes mostly from the air, since Photosynthesis essentially builds up glucose by only adding hydrogen to CO₂. The 2 H₂O → 2H₂ + O₂ reaction can be treated seperately, as was determined by Sam Ruben and Michael Kamen with ¹⁸O isotope tracing, i.e. in fact only the hydrogen in the carbohydrates comes from the soil, and ...


12

tl;dr: Sort of? Logically, either red or blue light should be sufficient. Chlorophyll a and chlorophyll b preferentially activate different photosystems, and both photosystems are required in green plants. Practically, we're in luck and someone has actually done the experiment. As the original study reports, plants need a little blue light to grow into ...


12

I'm not sure from your question if you're clear on the relationship between carbon fixation and 'energy', so just to be clear: carbon fixation in photosynthesis is the process of capturing CO2 and using it to store light energy in the form of carbohydrates. More CO2 capture = more harvestable 'energy'. Improving the efficiency of photosynthesis therefore ...


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