Photosynthesis - Science topic

The hydrological cycle (water cycle) is critical to the existence of the hydrosphere. It consists of four stages: evaporation, condensation, precipitation, and surface run-off. The heat of the sun evaporates water from lakes, seas, streams, and other bodies of water through the process of evaporation. Human contributions to greenhouse gases in the atmosphere are warming the earth's surface – a process which is projected to increase evaporation of surface water and accelerate the hydrologic cycle. In turn, a warmer atmosphere can hold more water vapor. It may stay in the hydrosphere or geosphere for a long time (such as in aquifers) or it may very quickly return to the atmosphere. These processes that transform and transfer water within the Earth's system occur continuously over time but at different rates in different places. Evaporation and transpiration transform liquid water into vapor, which ascends into the atmosphere due to rising air currents. Cooler temperatures aloft allow the vapor to condense into clouds. The water cycle consists of various complicated processes that move water throughout the different reservoirs on the planet. The major processes involved are precipitation, evaporation, interception, transpiration, infiltration, percolation, retention, detention, overland flow, through flow, and runoff. The water cycle provides fresh water for all living things on Earth, which make up the biosphere. The hydrosphere consists of all the water on the planet. The water cycle refers to the cycling of the water within this hydrosphere. Photosynthesis by land plants, bacteria, and algae converts carbon dioxide or bicarbonate into organic molecules. Organic molecules made by photosynthesizers are passed through food chains, and cellular respiration converts the organic carbon back into carbon dioxide gas. The food chain, plants move carbon from the atmosphere into the biosphere through photosynthesis. They use energy from the sun to chemically combine carbon dioxide with hydrogen and oxygen from water to create sugar molecules. Cellular respiration is the process by which organic sugars are broken down to produce energy. It plays a vital role in the carbon cycle because it releases carbon dioxide into the atmosphere. This means that cellular respiration can be thought of as the opposite of carbon fixation in the carbon cycle. The main carbon cycling processes involving living organisms are photosynthesis and respiration. These processes are actually reciprocal to one another with regard to the cycling of carbon: photosynthesis removes carbon dioxide from the atmosphere and respiration returns it. Photosynthesis releases energy, and cellular respiration stores energy. Photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Nutrients like nitrogen and phosphorous in soils are essential for producers. The CO2 released during decomposition can then be used by plants during photosynthesis. Thus, the matter in once-living consumers (and producers) is recycled back into new producers. Photosynthesis makes glucose which is used in cellular respiration for making ATP. The glucose is then transformed back into carbon dioxide, which is used in photosynthesis. It helps cells to release and store energy.

Javad Fardaei: Hi Mr. Fardaei, thank you very much for your insight. However, I think quantum mechanics doesn't necessarily refer to the "mechanical" behaviour of atoms. I believe it refers to the various branches of physics and how they apply to subatomic occurrences. But I do understand where you are coming from and will take your advice into consideration.

I agree with Rana Hamza Shakil that bacterial cells do not have chloroplast thus they cannot perform photosynthesis. Within the cell membrane, reaction centres are present which absorb light energy. The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis. They are anaerobic or microaerophilic, and are often found in hot springs or stagnant water. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, and so do not produce oxygen.Some types of bacteria are autotrophs. Most autotrophs use a process called photosynthesis to make their food. In photosynthesis, autotrophs use energy from the sun to convert water from the soil and carbon dioxide from the air into a nutrient called glucose. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, and so do not produce oxygen. Instead, they use hydrogen sulfide, which is oxidized to produce granules of elemental sulfur.Within the prokaryotic domain, there are five main groups of bacteria that perform tetrapyrrole-based photosynthesis. They are proteobacteria (also known as purple bacteria), heliobacteria, Chloroflexi, Chlorobi and cyanobacteria.Anabaena sp. PCC 7120 is a filamentous cyanobacterium consisting of a few hundred of vegetative cells, which perform oxygenic photosynthesis. Upon nitrogen deprivation, heterocysts, which are specialized cells for nitrogen fixation, are differentiated from vegetative cells at semiregular intervals. Some bacteria are able to use a process called photosynthesis to convert energy from sunlight into another form of energy they can use to grow. Within the bacteria, structures known as photosystems are responsible for absorbing light and transferring the energy to other molecules. The Azotobacter is economically important for producing food additives, biofertilizers, etc. It is used for the synthesis of phytohormones and also in bioremediation. It is used to produce a biofertilizer called Azotobacterin. Hence, Azotobacter is non-photosynthetic. Cyanobacteria emerged on Earth about 2.5 billion years ago and are the morphologically most diverse group amongst prokaryotes and the unique bacteria able to perform oxygenic photosynthesis. Some varieties of bacteria use light to create their own food, just like organisms that use photosynthesis. However, these bacteria are not autotrophs, because they must rely on chemicals besides carbon dioxide for carbon.

Photosynthetic bacteria, most commonly cyanobacteria, are important primary producers in tidal flats and salt marshes. Deep-sea ecosystems depend on primary producers that harness chemical energy from inorganic molecules such as hydrogen sulfide. Producers, who make their own food using photosynthesis or chemosynthesis, make up the bottom of the trophic pyramid. Primary consumers, mostly herbivores, exist at the next level, and secondary and tertiary consumers, omnivores and carnivores, follow. Land plants, or autotrophs, are terrestrial primary producers: organisms that manufacture, through photosynthesis, new organic molecules such as carbohydrates and lipids from raw inorganic materials (CO2, water, mineral nutrients). Primary consumers are normally herbivores. They are also referred to as heterotrophs as they don't produce their own food. They largely rely on autotrophs, which are plants that produce their food through photosynthesis. These organisms use several other feeding strategies. Some bacteria, such as cyanobacteria and purple and green sulfur bacteria, engage in photosynthesis. Since bacteria don't have chloroplasts, photosynthetic pigments are found in their membrane folds. Sunlight supports the photosynthetic process used by producers whereby heat disperses into the atmosphere and oxygen is produced. Consumers use this oxygen and feed on the food provided by producers and give off heat and carbon-dioxide as they do so. Carbon dioxide plus sunlight forms the food of the producers. Plants are autotrophs, which mean they produce their own food. They use the process of photosynthesis to transform water, sunlight, and carbon dioxide into oxygen, and simple sugars that the plant uses as fuel. These primary producers form the base of an ecosystem and fuel the next trophic levels. Plants, blue-green algae, as well as some bacteria like purple and green-sulphur bacteria, perform photosynthesis. Photosynthesis occurs only in some bacteria such as cyanobacteria, which is a diverse group of cyanobacteria. They are also known as blue-green bacteria. In higher-order plants, photosynthesis occurs in the chloroplast.

Yes, it is correct that bacteria do not have chloroplasts (photosynthesizing cell organelle) as they are prokaryotic organisms. Still some of them can perform photosynthesis to prepare their food by themselves. Bacteria do not contain membrane-bound organelles such as mitochondria or chloroplasts, as eukaryotes do. However, photosynthetic bacteria, such as cyanobacteria, may be filled with tightly packed folds of their outer membrane. Bacteria are prokaryotic and unicellular organisms. They do not have a membrane-bound nucleus and other cell organelles. Bacterial cells do not have chloroplast thus they cannot perform photosynthesis. Only cells with chloroplasts plant cells and algal cells can perform photosynthesis. Animal cells and fungal cells do not have chloroplasts and, therefore, cannot photosynthesize. That is why these organisms, as well as the non-photosynthetic protists, rely on other organisms to obtain their energy. Both photosynthetic bacteria and plants contain chlorophyll, but the types of chlorophyll differ in their structure. As a result, chlorophyll in purple and green photosynthetic bacteria is bacteriochlorophyll, or BChl. Cyanobacteria are an exception, and contain chlorophyll similar to plants.Bacterial cells do not have chloroplast but yet some photoautotrophic bacteria perform photosynthesis due to the presence of chlorophyll incorporated in the membrane. Chlorophyll molecules are arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts.Bacterial cell do not have chloroplast but yet some photoautotrophic bacteria perform photosynthesis due to the presence of chlorophyll in cooperated in the membrane. Embedded in the cell membrane are reaction centers which specifically absorb light energy. Small vesicles associated with plasma membrane: Although bacteria cells do not possess chloroplast, some photoautotrophic bacteria are able to perform photosynthesis. The presence of chlorophyll integrated in the cell membrane accomplishes this. Chloroplasts are the organelles specialized in carrying out the photosynthetic process, which uses light energy to synthesize organic compounds; for this reason, they are common to all photoautotrophic eukaryotes. Cyanobacteria are a diverse group of photosynthetic bacteria that were previously known as 'blue green algae'. These prokaryotes perform photosynthesis even though they do not have chloroplast. Bacterial cell do not have chloroplast but yet some photoautotrophic bacteria perform photosynthesis due to the presence of chlorophyll in cooperated in the membrane. Embedded in the cell membrane are reaction centers which specifically absorb light energy.

Plants, blue-green algae, as well as some bacteria like purple and green-sulphur bacteria, perform photosynthesis. The process of photosynthesis in bacteria and plants is different. Photosynthesis occurs in plants and some bacteria, wherever there is sufficient sunlight, be it on land, in shallow water, or even inside and below clear ice. All photosynthetic organisms use solar energy to turn carbon dioxide and water into sugar (food) and oxygen: CO2 + 6H2O -> C6H12O6 + 6O2. Yes, photosynthesis occurs in some bacteria, e.g. purple and green-sulphur bacteria and cyanobacteria. Photosynthetic pigments are present within the membrane infoldings of bacteria as they lack chloroplasts. Cyanobacteria or cyanobacteria contain chlorophyll and may perform oxygenic photosynthesis like plants. Most life on Earth depends on photosynthesis. The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O2) and chemical energy stored in glucose. Some bacteria also perform anoxygenic photosynthesis, which use bacteriochlorophyll to split hydrogen sulfide as a reductant instead of water, and sulfur is produced as a byproduct instead of oxygen. The photosynthesis process in bacteria and plants differs. Bacterial photosynthesis is primarily an anoxygenic process in which O2 is not evolved, whereas plant photosynthesis is an oxygenic process in which O2 is evolved. Chlorophyll a and b are photosynthetic pigments involved in the process. Bacteriochlorophyll is a photosynthetic pigment found in prokaryotic photosynthetic bacteria or phototrophic bacteria. In contrast, chlorophyll is a photosynthetic pigment found in plants, algae and cyanobacteria. Therefore, this is the key difference between bacteriochlorophyll and chlorophyll. Photosynthesis takes place in the chloroplasts of higher organisms. Whereas it occurs in cytoplasm in bacteria. Thus they are called as photoautotrophic bacteria. Process of bacterial photosynthesis: Bacterial photosynthesis is based on cyclic photophosphorylation mechanism and only one pigment system (PS-I) is involved. During the process, bacteriochlorophyll absorbs light and this light energy raises the chlorophyll molecule to an excited state.

Photosynthetic bacteria can produce various types of physiological active substance such as vitamin B(12), ubiquinone (coenzyme Q10), 5-aminolevulinic acid (ALA), porphyrins and RNA. In particular, photosynthetic bacterial ALA was commercially applied to cancer diagnosis and treatment. Chlorophyll is a compound that is found in all photosynthetic plants. It is present in the chloroplast of the leaves. In bacteria, chlorophyll is absent. It is also known as the primary photosynthetic pigment. Photosynthetic bacteria maintain energy for growth and metabolism from organic acids or carbon monoxide. They grow on most of the organic acids involved in the tricarboxylic acid cycle and produce hydrogen and carbon dioxide. Bacterial photosynthesis is primarily an anoxygenic process in which O2 is not evolved, whereas plant photosynthesis is an oxygenic process in which O2 is evolved. Chlorophyll a and b are photosynthetic pigments involved in the process. Since bacteria don't have chloroplasts, photosynthetic pigments are found in their membrane folds. Blue-green algae, often known as cyanobacteria, have chlorophyll and are able to perform oxygenic photosynthesis just like plants. While plants evolve oxygen, other microorganisms do anoxygenic photosynthesis.Inoculated with photosynthetic bacteria (PSB) are confirmed to form a symbiotic relationship with crop roots, thereby promoting root development, and improving crop root nutrient and water uptake capacity. They are self-supporting organisms that produce sugars to stimulate other soil life. They can also build amino acids for the benefit of plants and other organisms. The process of photosynthesis in bacteria and plants is different. Bacterial photosynthesis is mostly an anoxygenic process, here O2 is not evolved, whereas plant photosynthesis is an oxygenic process and O2 is evolved during the process. Because bacteria are prokaryotic, they do not have a nucleus and no membrane-bound organelles. In contrast, plants and animals are made up of eukaryotic cells, which mean they have a nucleus and membrane-bound organelles like mitochondria or golgi apparatus. Bacteria change the soil environment so that certain plant species can exist and proliferate. Where new soil is forming, certain photosynthetic bacteria start to colonize the soil, recycling nitrogen, carbon, phosphorus, and other soil nutrients to produce the first organic matter. Bacteriochlorophylls are found in phototrophic bacteria or anoxygenic phototrophs such as purple bacteria, heliobacteria and green sulfur bacteria, etc. Meanwhile, chlorophylls are found in oxygenic phototrophs such as plants, algae and cyanobacteria. The former is a blue-green pigment and the latter is a yellow-green pigment. They give their characteristic green colour due to the strong absorbance of red and blue light. The other types of chlorophyll include chlorophyll c1, c2, c3, d, e and chlorophyll f.

Land plants, or autotrophs, are terrestrial primary producers: organisms that manufacture, through photosynthesis, new organic molecules such as carbohydrates and lipids from raw inorganic materials (CO2, water, mineral nutrients. They use the process of photosynthesis to transform water, sunlight, and carbon dioxide into oxygen, and simple sugars that the plant uses as fuel. These primary producers form the base of an ecosystem and fuel the next trophic levels. Without this process, life on Earth as we know it would not be possible. Producers, a major niche in all ecosystems, undergo photosynthesis to produce food. All producers are autotrophic, or "self-feeding". In terrestrial ecosystems, producers are usually green plants. Freshwater and marine ecosystems frequently have algae as the dominant producers. The most common are photoautotrophs—producers that carry out photosynthesis. Trees, grasses, and shrubs are the most important terrestrial photoautotrophs. In most aquatic ecosystems, including lakes and oceans, algae are the most important photoautotrophs. A producer is an organism which produces its own food through photosynthesis. 3. A consumer is an organism which does not make its own food but must get its energy from eating a plant or animal. Plants are considered producers since they can produce their own food from non-living sources through a process known as photosynthesis. In photosynthesis, plants use sunlight and carbon dioxide to produce organic compounds. A producer in biology is also known as an autotroph. Thus, producers in science are organisms that can make their own food through biochemical processes. Producers are an important part of the food web in ecosystems. A food web is a diagram that shows the transfer of energy through different species. Plants and algae are able to make their own food using energy from the sun. These organisms are producers because they produce their own food. Green plants use sunlight and carbon dioxide from the atmosphere to produce carbohydrates by the process of photosynthesis. Since, plants produce food for themselves, they are known as producers. Plants are considered producers since they can produce their own food from non-living sources through a process known as photosynthesis. In photosynthesis, plants use sunlight and carbon dioxide to produce organic compounds. These organic compounds become the energy source for many other organisms within an ecosystem. They use the process of photosynthesis to transform water, sunlight, and carbon dioxide into oxygen, and simple sugars that the plant uses as fuel. These primary producers form the base of an ecosystem and fuel the next trophic levels. Without this process, life on Earth as we know it would not be possible. As producers are the first level in a food system, they provide energy to the entire system. They do not rely on other organisms for food but instead get energy from the sun, which they convert into useful chemical energy. This conversion supports other organisms in the system thereby sustaining the food chain.

Photosynthetic reactions divided into two stages: Light reaction - light energy is absorbed and converted to chemical energy such as ATP and NADPH Dark reaction- carbohydrates made from CO2 is stored in ATP & NADPH. Photosynthetic bacteria contain light absorbing pigments and reaction centres and capable of converting. In higher-order plants, photosynthesis occurs in the chloroplast. Bacteria do have chloroplasts. However, cyanobacteria possess the photosynthetic pigment chlorophyll in flattened sac-like structures called thylakoids, which are present in the cytoplasm. The photosytem I is present in the green and purple bacteria that conduct the bacterial photosynthesis where as the photosystem II is present in the cyanobacteria that conduct the normal plant photosynthesis. Bacterial photosynthesis involves two types of photosynthesis which are oxygenic and Anoxygenic photosynthesis. Photosynthetic bacteria contain light absorbing pigments and reaction centres which convert sunlight into chemical energy. This type of photosynthesis involves oxygen release. Oxygenic photosynthesis refers to the photosynthesis that occurs in plants, algae, and cyanobacteria in which the final electron acceptor is water. Anoxygenic photosynthesis refers to a form of photosynthesis used by certain bacteria, in which oxygen is not produced. Several groups of bacteria are capable of conducting anaerobic photosynthesis including green sulfur bacteria (GSB), purple sulfur bacteria (PSB), purple non-sulfur bacteria (PNSB), Acidobacteria, Heliobacteria, and both red and green filamentous phototrophs such as Chloroflexi. Yes, photosynthesis occurs in some bacteria, e.g. purple and green-sulphur bacteria and cyanobacteria. Photosynthetic pigments are present within the membrane infoldings of bacteria as they lack chloroplasts. Cyanobacteria or cyanobacteria contain chlorophyll and may perform oxygenic photosynthesis like plants. Within the prokaryotic domain, there are five main groups of bacteria that perform tetrapyrrole-based photosynthesis. They are proteobacteria, heliobacteria, Chloroflexi (filamentous bacteria also known as green non-sulfur bacteria), Chlorobi and cyanobacteria.

Turgor pressure is the pressure applied on the wall of the plant cell by the fluids inside the cell. The more water is in the cell (the fuller the cell) and the bigger the pressure. Management of turgor pressure provides a balance between CO2 intake and water loss, so that photosynthesis can occur. In order to survive, plants need to balance CO2 uptake for photosynthesis (A) with water loss via transpiration. By adjusting their aperture, stomata control gaseous exchange between the leaf interior, and the external atmosphere. Stomatal aperture is adjusted by moving solutes into or out of the guard cells.The roots lose water vapor to the soil, and the stem loses water vapor through the leaves. How do plant systems work together to maintain a balance of water inside the plant? Shoots control water absorption, and roots control water evaporation. Plants respond to droughts by partially closing their stomata to limit their evaporative water loss, at the expense of carbon uptake by photosynthesis. This trade-off maximizes their water-use efficiency, as measured for many individual plants under laboratory conditions and field experiments. Plants are nature's great water filters. They absorb water from the soil through their roots, use this water to maintain homeostasis, and whatever is left evaporates from open stomata across the epidermis of the plant. Stomatal movements control CO2 uptake for photosynthesis and water loss through transpiration, and therefore play a key role in plant productivity and water use efficiency. Plants maintain a balance between efficient photosynthesis and water loss through various adaptations and mechanisms that regulate their stomata, the small openings on the surface of leaves and stems. Plants consume carbon dioxide which is released by the animals. This is how ​​plants help in maintaining a balance of oxygen and carbon dioxide in atmosphere. Leaves are sometimes reduced to spines. The thick cuticle on leaves reduces water loss. Some plants have stomata only on the lower side. Some of the plants have sunken stomata to reduce water loss. They absorb water from the soil through their roots, use this water to maintain homeostasis, and whatever is left evaporates from open stomata across the epidermis of the plant. Water balance is achieved in the body by ensuring that the amount of water consumed in food and drink (and generated by metabolism) equals the amount of water excreted. The consumption side is regulated by behavioral mechanisms, including thirst and salt cravings. Water is an important factor needed for photosynthesis so without proper water balance the plant has a risk of dying due to not getting the needed food/energy. Plants also need water for nutrients transfer to the plant from the soil that is carried through the plant's stem to the areas needed through the osmosis.

Taichi Sugiyama , thank you for the link.

Yes, so-called "C2 photosynthesis" it is a new approach related to the fact, that through photorespiration a part of the captured carbon dioxide pool is incorporated into plant photosynthetic metabolism. See e.g.

The name is a little bit confusing, however... In biological sciences, we have lots of abbreviations, acronyms etc. They overlap sometimes, which brings a little mess.

Best regards,

Renata

There is some evidence to suggest that the growth of cyanobacteria undergoes complete cessation under conditions of extremely high light intensity, depending on the species and strain of cyanobacteria, the duration and frequency of exposure, and the availability of nutrients.

Cyanobacteria are photosynthetic microorganisms that can adapt to various light conditions by adjusting their photosynthetic apparatus and metabolism. However, when the light intensity exceeds their capacity for light harvesting and utilization, they can experience photoinhibition, oxidative stress, and damage to their photosystems and other cellular components (1),(2).

Some studies have reported that cyanobacterial growth can be completely halted at very high light intensities, such as those exceeding 1000 μmol(photons) m-2s-1. For example, a study by Muhetaer et al. (2020) found that two cyanobacteria species, Pseudanabaena galeata and Microcystis aeruginosa, showed a significant decline in growth rate and biomass production when exposed to 600 μmol(photons) m-2s-1 for two or eight days (3). Another study by Yoshikawa et al. (2021) found that the cyanobacterium Synechocystis sp. PCC 6803 showed a complete cessation of growth when exposed to 2000 μmol(photons) m-2s-1 for 24 hours (4).

However, other studies have shown that cyanobacterial growth can be maintained or even enhanced at high light intensities, depending on the acclimation and adaptation mechanisms of the cyanobacteria. For instance, a study by Silveira et al. (2019) found that the cyanobacterium Microcystis wesenbergii showed an increased growth rate and toxin production when exposed to 1000 μmol(photons) m-2s-1 for 12 days (5).

The response of cyanobacterial growth to high light intensity may also depend on the availability of nutrients, such as nitrogen and phosphorus, which are essential for photosynthesis and cellular metabolism. Some studies have suggested that nutrient limitation can exacerbate the negative effects of high light intensity on cyanobacterial growth, while nutrient enrichment can mitigate or reverse them (5).

Therefore, the answer to your question may vary depending on the specific conditions and parameters of your experiment. However, based on the available literature, it seems possible that the growth of Synechocystis sp. PCC 6803 can be completely halted at very high light intensities, such as those exceeding 1000 μmol(photons) m-2s-1, especially if the exposure period is long or repeated, and if the nutrient supply is low or limiting.

(1) Light intensity and spectral distribution affect chytrid infection of .... https://www.cambridge.org/core/journals/parasitology/article/light-intensity-and-spectral-distribution-affect-chytrid-infection-of-cyanobacteria-via-modulation-of-host-fitness/D491C209ABF241D5A5D28DBDBDFE0FA9.

(2) Enhancing photosynthesis at high light levels by adaptive ... - Nature. https://www.nature.com/articles/s41477-021-00904-2.

(3) Effects of Light Intensity and Exposure Period on the Growth and Stress .... https://www.mdpi.com/2073-4441/12/2/407.

(4) Mutations in hik26 and slr1916 lead to high-light stress tolerance in .... https://www.nature.com/articles/s42003-021-01875-y.

(5) Effects of light intensity and nutrients (N and P) on growth, toxin .... https://link.springer.com/article/10.1007/s10750-021-04649-z.

If plants have less light, they photosynthesize more slowly. The speed of photosynthesis increases with greater light intensity, though it ultimately levels off once the plant has as much light as it needs. Carbon dioxide concentration is another factor that affects photosynthesis. In some cases, poor environmental conditions damage a plant directly. In other cases, environmental stress weakens a plant and makes it more susceptible to disease or insect attack. Environmental factors that affect plant growth include light, temperature, water, humidity and nutrition.

Decreased concentrations of total non-structural carbohydrates (TNC) are observed with an increasing nitrogen supply. Your research is correct :)

See: https://doi.org/10.1093%2Faob%2Fmch210

During the carbon cycle, animals and plants add carbon dioxide to the atmosphere through cellular respiration, and plants remove carbon dioxide through photosynthesis. The burning of fossil fuels releases more carbon dioxide into the atmosphere, contributing to global warming. Carbon follows a certain route on earth, called the carbon cycle. Through following the carbon cycle we can also study energy flows on earth, because most of the chemical energy needed for life is stored in organic compounds as bonds between carbon atoms and other atoms.

Nitrogen Cycle is a biogeochemical process through which nitrogen is converted into many forms, consecutively passing from the atmosphere to the soil to organism and back into the atmosphere. It involves several processes such as nitrogen fixation, nitrification, denitrification, decay and putrefaction. Photosynthesis by land plants, bacteria, and algae converts carbon dioxide or bicarbonate into organic molecules. Organic molecules made by photosynthesizers are passed through food chains, and cellular respiration converts the organic carbon back into carbon dioxide gas.

Linsheng Wu It is a really important and interesting question. From my opinion, it depends on the drought condition. The results may be different for mild and servere droughts. You mentioned crops, but there are many cultivars. Some of them are susceptible, and some are resistant to water shortage. And the duration, the time of the drought may also alter the result. So I think it is hard to draw a general conclusion. I have a similar question, but I would state it like this: how does the relationship between phiF and phiP (and their diurnal patterns) change as the environment gets dryer? I think the work of Prof. van der Tol (2014) gives us a nice answer. But there are still problems remained, because the droughts involve mutiple factors and changes in both environment and plant.

Respiration is essential for growth and maintenance of all plant tissues, and plays an important role in the carbon balance of individual cells, whole-plants and ecosystems, as well as in the global carbon cycle. Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a byproduct. Cellular respiration converts oxygen and glucose into water and carbon dioxide. Water and carbon dioxide are by products and ATP is energy that is transformed from the process.

Temperature is a critical factor affecting plant growth. Each plant species has a suitable temperature range. Within this range, higher temperatures generally promote shoot growth, including leaf expansion and stem elongation and thickening. However, temperatures above the optimal range suppress growth. The rate of photosynthesis increases as the temperature rises. During photosynthesis, a temperature of more than 40 °C slows down the process. Because it is an enzyme-controlled process, this is the case. It occurs as a result of enzymes being involved in temperature-sensitive chemical processes. As temperature increases the number of collisions increases, therefore the rate of photosynthesis increases. However, at high temperatures, enzymes are denatured and this will decrease the rate of photosynthesis. The impacts of climate change on agriculture include; Shortening of Growing Season Length (GSL), heat stress at critical reproductive stages and increased water requirements of crops. These factors cause a decrease in yield in arid and semi- arid regions by about 6 -18%.

Extensive work has been done and published in this field. That is not to say it's unchallengeable!

So, I see you have posted a number of questions recently to ResearchGate, a professional website for research scientists. The wording of your questions appears to be copied from exams. If so, stop this right now. It an inappropriate use of this webpage and counts as plagiarism/academic misconduct.

In my opinion Cynodon dectylin is the most common plant.

The following link is also very useful RG link:

To optimise most plant growth it is recommended that they receive 500–1000 µmols of PAR light for every m² (PPFD). Less than this and growth rates will be low :)

There may not be direct to the point, however, I advice you read the following articles.

Thank you!

Senescence is the final stage of plant development and is characterized by a series of programmed disassembly and degenerative events. As leaves age, chloroplast degeneration is initiated, paralleled by catabolism of macromolecules, including nucleic acids, proteins and lipids. The released nutrients are exported to other developing organs, such as new buds, young leaves, flowers or seeds, which leads to increased reproductive success.

However, during photosynthesis, excess natural or artificial light can cause photo-oxidative damage to chloroplasts. It has been shown that chlorophagy, the intracellular destruction of chloroplasts, is induced by exposure to UV-B irradiation (280–315 nm) and high light. Researchers have also demonstrated that entire photo-damaged chloroplasts are transported to the plant cell vacuole for destruction.

i sorry i am not measure chlorophyll in the leaf but i measured

chlorophyll/unit photosynthesis/unit chlorophyll, in coral reef only

Light response curves can be based on either gas exchange or chlorophyll fluorescence parameters (including ETR and NPQ). In LRCs, we analyze a photosynthetic parameter relative to light intensity instead of time. This allows us to understand the dynamics of the photosynthetic apparatus relative to light intensity and understand such things as optimal light intensities, define light limiting environments, and more.

With the data of each variables, PCA can give good results

when I was a student, we were taught that it was about 1%

Please have a look at some of these PDFs...

Stomatal parts are the ones through where the photosynthesis gas for exchange passes, and defintely if the density of the stomata bodies/pores increase per given area of leaf, then there will be an increase on photosynthesis.

Despite having the same roots of origin, namely quantum superposition, coherence and entanglement are conceptually different.

Dear @Muhammad Arslan Ashraf Please check whether the attached pdf and below mentioned links could serve your purpose:

Philipp Girr Thanks, you made my day.

Also, kindly check:

Emerging approaches to measure photosynthesis from the leaf to the ecosystem:

Pollution (addition of gases into the air from human activities, such as carbon dioxide) is the main cause of climate change today.

Trees absorb some of the CO2 from the air, but people have been cutting down trees for all kinds of reasons, such as building roads, houses, etc. Therefore, unless you plant more trees and some are doing that, the CO2 builds up in the atmosphere and has the tendency to absorb heat that is being sent back into space. Instead of going to space this (outgoing) heat stays in the air and warms up the air (global warming).

Electrophoresis results are at best semi-quantitative. Starting with loading errors and gel-to-gel variability, there are many things that can go wrong. As with all dye-binding assays, colour yield depends on protein. If you have standards (in the same gel!), you'd at least get an idea what the error margins are.

If the staining is not too strong (in the linear range of the densitometer), you could scan the gels and integrate the peaks. Laser-based densitometers are better at this than simple scanners, because of a larger linear range (up to 4 AU). Even better results may come from fluorescent dyes like RuBPS and fluorescent scanners, simply because fluorescence starts from zero, whilst in absorbance you measure the small difference of two large numbers.

You could also cut out the bands, elute the bound dye and determine that photometrically.

Try BiGGR

dynamicFBA

fbar

sybilDynFBA

Have fun and Happy Research!

I recommend a paper "Photosynthesis research a model of bridge fundamental sciences , translational products and socio-economic considerations in agriculture". Journal Experimental Botany, 2020

Successes....

Please take a look at the following useful RG links.

Hi Johanna

Leaf temperature usually depends on both air temperature and vapor pressure deficit (VPD). Increasing air VPD with a good watering will lead to lower leaf temperature compared to air. It also depends on the boundary layer, but as Licor leaf chamber has a mixing fan it will blow away the boundary layer which leads to decrease in leaf temperature. If the mixing fan can be turned off, then do it first.

Then try to decrease VPD by increasing humidity of the chamber by controlling air flow rate, or of it has a humidity control, then use it.

These two methods can increase leaf temperature to a higher level. Increasing light intensity also can lead to temperature increase, but use sunlight if you can, as its wavelength temperature is significantly higher than Licor's light.

If you couldn't reach higher levels you have to give a water stress to the plant so that it decrease the transpiration rate.

All of these will finally lead to significant damage to the photosynthetic apparatus (when temperature increases above ~37 (depending on the species), so you can't hold it for long. Attached photo shows what happens to the leaf when it is kept in high temperature for too long (thermal degradation of chlorophyll), which I experienced in a branch enclosure system.

Hope it helps

Ehsan

Dear Dr Azad,

There are a few more aspects if I look at the answers given. Not all wavelengths are absorbed with the same efficiency. Green light is in this respect the least efficient. Several scientists have proposed that due to this inefficiency green light can penetrate deeper in a leaf and drive photosynthesis there. At the same time blue light is known to be absorbed by phototropins that can drive chloroplast movements and thereby affect the light absorption profile of a leaf on a minutes time scale. Red light does not do this. Phytochromes that are sensitive to red and far-red light are known to affect plant morphogenesis, etc. In other words, your question depends on the time scale considered.

Dear Namitha L H

Light, its intensity and quality, are factors that affect the concentration of different chlorophylls, especially the ratio of chlorophyll a to chlorophyll b. Plants that get abundant sunlight have less overall chlorophyll concentration and higher amounts of chlorophyll a than chlorophyll b. Plants that grow under shade, like those in densely forested areas, have a high overall chlorophyll concentration, but have more chlorophyll b than chlorophyll a.

Hybrid plants of maize, pearl millets and sorghum have more tolerance to shading stress (due to increased plant density) than those of open-pollinated varieties.

Under similar growing conditions, I did never emprically observe any difference in color intensity of leaves of hybrid and open-pollinated varieties of these crops. Therefore, dark green leaves appear to be a consequence of shading effect. I agree with J.D. Franco-Navarro and Francisca Higueras-Fredes

Best wishes, AKC

Are you looking for photosynthetic ability of periphyton microbes..??. If so , , why not to compare with rhzisosphere microbes as well...

فتوسنتزمتر

I agree with omar

I think that changing the C3 plants to C4 will require large genetic and physiological resources to make the most of the unit of land and water in the long term, but it is possible in the short term to do some easy and simple methods for this purpose, which is to growing C3 plants with C4 in the same land

CID Photosynthesis System

Dear Stefano,

On the one hand, the manufacturer should provide the PAR value emitted by the diode. On the other hand, you can visit colleague at the nearest physics / optics department and ask for an exact measurement for your instrument. You can also try to measure with an ordinary PAR meter, although the measurement will be probably burdened with a significant error. Either way, if you measure a value above 3000 everything is ok.

Plants have evolved in sunlight (~2000 PAR), so 3000 and more are likely to saturate the photosynthetic apparatus.

Many Icfre institutions also have PP systems. You may contact them for more info.

In order for cosmic rays to arrive at the surface of the earth, you have to get rid of the solar wind (which blocks cosmic rays) something not likely to happen.

Plants utilize light as a source of information in photomorphogenesis and of free energy in photosynthesis, two processes that are interrelated in that the former serves to increase the efficiency with which plants can perform the latter. Only one pigment involved in photomorphogenesis has been identified unequivocally, namely phytochrome. The thrust of this proposal is to investigate this pigment and its mode(s) of action in photosynthetically competent plants. Our long term objective is to characterize phytochrome and its functions in photosynthetically competent plants from molecular, biochemical and cellular perspectives. It is anticipated that others will continue to contribute indirectly to these efforts at the physiological level. The ultimate goal will be to develop this information from a comparative perspective in order to learn whether the different phytochromes have significantly different physicochemical properties, whether they fulfill independent functions and if so what these different functions are, and how each of the different phytochromes acts at primary molecular and cellular levels.

Dear Riya Mehrotra,

Hi, SEM is often used to view the surface characteristics and properties of organs. You must use TEM to view intracellular organelles.

Best regards,

Saeed

Thank you for the response. Yes, we are using a CO2 cartridge and it helps. We do not have a LED light source and hence this was the main reason for the variation. We are in the process of procuring the light source.

Recent findings in my lab showed that optical sensors measuring chlorophyl concentration give better results relative to indices such as NDVI. Chlorphyl concentration measurmements were comparable to fAPAR ( Fraction of Absorbed Photosynthetically Active Radiation) measurements.

Eva Maleckova

What is you actually want to do?

Because in your question it seems you want to do a lot of things which does not seem to be done as one thing.

1. How to identify differences across a big number of long protein alignments?

>> Do you mean difference within one alignment (single protein), or differences across different alignments (several proteins)?

2. You are also thinking about finding new genes, that is a bit different approach.

If you can enlist exacly what you want to do, it would be easier to answer.

Dear Sirs, if you agree with a contribution on this forum you can show your appreciation by recommending an answer or a question.

Now please stop diluting actual information with your spam answers.

No. Maybe uplland rices resistance to Pyricularia leaf blight. But on soybeans I know many geens to target. Sorry.

Dear Yoslen

Chlorophyll mainly determines the photosynthetic rate and primary productivity in plant. Chlorophyll content will be changed with the change of external environment, which could further lead to the photosynthetic capacity change. Therefore, chlorophyll content could be used as an important diagnostic indicator for plant growth study. The assessments of chlorophyll contents are based on the extraction of chlorophyll with solvents from the destructive leaf followed by spectrophotometric determination.

Li, Y., Sun, Y., Jiang, J. et al. Spectroscopic determination of leaf chlorophyll content and color for genetic selection on Sassafras tzumu. Plant Methods 15, 73 (2019).

Take a look at the article:

http://www.paper.edu.cn/scholar/showpdf/OUT2EN4IOTD0kxeQh

Pleas read the paper " Photosystem I, when excited in the chlorophyll Q y absorption band, feeds on negative entropy

Could you please look at this website:

Best regards,

Quynh Nguyen

Hy dear Habib Athar

you can use of this article and words that i sent for you.

Thank you.

Hi

In the attached article, you can get some good information on comparing photosynthesis of C3, C4 and CAM plants.

If the size of a small water system (confinement) coincides with that of a semiconductor, then the photocatalytic decomposition of water is enhanced. Quantum entanglement seems to be happening. This is the subject of our patent application.

Dear Vjacheslav Fisenko,

In our region (drylands), we found that the results of the MSAVI2 and GDVI indices are working better than the NDVI.

Good luck and best regards.

We had a similar problem. We ended up having a tiny break in the thermocouple wire which was used to measure leaf temperature. We ended up swapping it out and the problem was fixed right away. But Joshua is right, contact support, they will know exactly what to do

Hello dear ,

I think that is troposphere

Dear Samiksha,

during winter months when the water column is oxic, Fe oxide reduction only occurs in the strongly reducing sediment column. Reduced Fe(II) diffuses to the sediment-water interface where it is immediately oxidized to Fe oxide. As a result, there is no buildup of dissolved Fe in the water column during winter. In early summer the lake becomes thermally stratified. As summer progresses, oxygen is consumed by biological processes and the bottom waters become anoxic. Reductive dissolution of Fe oxide continues to occur in the sediments. Fe(II) diffuses into the anoxic bottom water and is oxidized at the oxycline forming a peak in particulate Fe in the water column. Below the oxycline, where the water is strongly reducing, dissolved Fe(II) is stabilized and its concentration increases with time. In early winter, mixing processes re-oxygenate the entire water column and Fe(II) is rapidly oxidized and precipitated.

Here is a classic work on the subject by Mortimer: https://www.jstor.org/stable/2256395?origin=crossref&seq=1#page_scan_tab_contents

After creating an account (free), you can read the article for free.

With best regards,

Johannes

With rise in temperature the productivity of C₄ plants would increase, while those of C₃ plants would decrease due to increase in rate of 'photorespiration'. Thus plants with C₄ pathway of photosynthesis would be benefited from climate change.

Some more alternatives below. I have used a custom-made solution for measuring gas exchange in shoot apex in cucumber and tomato plants. Maybe relevant! Good luck!

Besides other parameters mentioned by Kathryn, did you look at stomatal density?

Hi, here is R code for building a loop which fits a light curve model (Platt et al. 1980) to the data, extracts the coefficients into a data frame and plots the results into tiff files (one file for each fitted curve) using "phytotools" package mentioned above. This is largely based on the code examples provided by the authors of the phytotools package. One should be able to fit the other models in the package also by modifying the plot and fitting sections of the script (model equations I think are specified in phytotools documentation). This is a bit late answer but I'll upload it in any case if someone still finds this useful.

In general crop rotation reduces the green house gasses, for example corn rotate with soyabean or wheat is found to be very effective in reducing GHG.