Keyword Analysis & Research: bvsd

wiley.com

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2000.45.5.1130

Accessory pigments versus chlorophyll a concentrations within the euphotic zone: A ubiquitous relationship Charles C. Trees Center for Hydro-Optics and Remote Sensing, San Diego State University, San Diego, California 92120 ... en to reduce the uncertainties in bio-optical algorithms that generate satellite derived products. As a result of this ... Author: Charles C. Trees, Dennis K. Clark, Robert R. Bidigare, Michael E. Ondrusek, James L. Mueller Publish Year: 2000

Author: Charles C. Trees, Dennis K. Clark, Robert R. Bidigare, Michael E. Ondrusek, James L. Mueller

Publish Year: 2000

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sciencedirect.com

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/accessory-pigment

4.1 Vegetable Sources of β-carotene and Its Impact on Human Health 4.1 Vegetable Sources of β-carotene and Its Impact on Human Healthβ-carotene participates as an accessory pigment in light absorption and energy dissipation in photosynthesis, as well as general antioxidant functions. Therefore, β-carotene can be found in leaf, fruit, and even root tissues of many vegetable crops (Table 40.1). The root crop carrot (Daucus carrota L.) has some of the highest concentrations of β-carotene. β-carotene levels in carrot can range from 3.2 to 6.1 mg/100 g fresh weight [47]. However, cruciferous leafy vegetable crops can have concentrations equal to, or higher than carrot. Values in kale and collards are reported to range from 3.8 to 10.0 mg β-carotene/100 g fresh weight [48,49].Vitamin A deficiency is the single most important cause of childhood blindness in developing countries around the world, and subclinical levels can contribute significantly to increased child mortality [44]. Vitamin A can be consumed in the diet as both preformed retinoids from animal tissues and as pro-vitamin A carotenoids found in plant tissues. The major sources for vitamin A for most populations worldwide are the plant-based pro-vitamin A carotenoids. The same factors that may limit carotenoid bioavailability (see Section 5) also affect vitamin A status. The bioconversion of pro-vitamin A carotenoids is mediated by a predominantly cytosolic enzyme, β-carotene 15,15′-deoxygenase, present in the intestinal mucosa, the liver, and the corpus luteum [44]. The activity of this enzyme is most efficient for β-carotene; however, other carotenoids can be metabolized to yield retinal (α-carotene and cryptoxanthins). After conversion of the pro-vitamin A carotenoids, vitamin A is transported and stored in the liver mainly as retinyl esters. Metabolism of vitamin A occurs following esterification, conjugation, oxidation, and/or isomerization reactions, after which retinal forms participate in maintenance of epithelial cell differentiation, reproductive performance, and visual functions [44].The chemical structure of β-carotene makes it an efficient in vitro neutralizer of singlet oxygen (1O2), and to a lesser extent, an effective agent at reducing lipid peroxidation. Early research that demonstrated both its antioxidant and antigenotoxic properties resulted in β-carotene being one of the most extensively studied cancer chemopreventative agents in research supported by the National Cancer Institute [50]. Unexpectedly, results from three separate clinical trials revealed that β-carotene supplements, either alone or in combination with vitamin E, administered for cancer prevention actually increased incidences of lung cancers in heavy smokers and asbestos workers [51,52]. Based on the results showing pro-oxidant behavior in the presence of tobacco smoke, it appears plausible that β-carotene could be causing stimulation of pre-existing latent tumors under these conditions, rather than initiating tumorigenesis [50]. However, research showed β-carotene supplementation in animal models significantly increased phase I carcinogen enzymes in the lung, including the cytochrome P450s of CYP1A1, CYP1A2, CYP3A, CYP2B1, and CYP2A [53]. It is hypothesized that high β-carotene supplementation may increase tissue oxidative stress, or could act synergistically with known carcinogenic chemicals (present in tobacco smoke) in CYP induction. In a current review on the subject, Paolini et al. [50] clearly demonstrate that detrimental effects of individual β-carotene supplements are possible when subject individuals are exposed to environmental mutagens and carcinogens. The authors still encourage a diet high in fruit and vegetables, but warn of the possible dangers in consuming high concentrations of one or more isolated supplements.URL: https://www.sciencedirect.com/science/article/pii/B9780123746283000402S.D. Pradeep, ... Pramod Kumar, in , 20229.5.2 Chlorophylls 9.5.2 ChlorophyllsThe photosynthetic processes are largely governed by chlorophylls and accessory pigments. Chlorophylls serve as an essential factor in describing health of leaves. Chlorophylls harness sunlight and store it in the chemical form (Richardson, Duigan, & Berlyn, 2002). Photosynthetic activity can be judged by photosynthetic pigments. In higher plants, reduction in the level of chlorophylls is being seen under stressful conditions (Chen et al., 2015; Su et al., 2014; Wang et al., 2014). High-temperature stress has various symptoms on wheat, they are primarily; disfunctioning of chloroplast due to structural and functional disorders, reduction in chlorophyll content, and neutralization of chloroplastic enzymes (Reynolds, Van Ginkel, & Ribaut, 2000). During grain-filling stage, decline in overall photosynthetic rate under high temperature is observed due to loss in chlorophyll and differences in the ratio of chlorophyll a to chlorophyll b due to early mortality or drying of leaf (Harding, Guikema, & Paulsen, 1990). Under heat stress, production of chlorophyll is hampered and this thereby increases the rate of leaf senescence (Gupta, Gupta, & Kumar, 2000; Paul et al., 2005). CO2 assimilation is also affected by heat stress, both directly and indirectly. Effects are primarily divided into two major groups. The first category comprises of fully reversible inhibitory effects. As the name suggests, these effects disappear as soon as the temperature gets normalize. The most noticeable reversible effect is caused due to reduction of CO2 solubility and this is again caused by an increase in photorespiration (Ku & Edwards, 1977; Von Caemmerer & Quick, 2000). The decrease in CO2 solubility causes decrease in rate of photosynthesis and also in the activity of the enzyme rubisco activase (Haldimann & Feller, 2005; Salvucci & Crafts-Brandner, 2004). The second group of damage is irreversible type. This type of damage has long-lasting effect on plant metabolism. The damaged structure should be repaired as soon as possible to attain the maximum photosynthetic capability of the plant.In order to adjust to the varying temperatures, there are modifications in saturation levels of membrane lipids. Various parameters like membrane fluidity and permeability get modified in response to fluctuating temperature (Zheng, Tian, Zhang, Tao, & Li, 2011). It is considered desirable to have high chlorophyll content in wheat crop because chlorophyll reduction occurs under stressful conditions (Chen et al., 2015; Su et al., 2014; Wang et al., 2014). Chlorophyll content in leaves of wheat is proposed for high throughput selection for heat-tolerant genotypes (Ristic, Bukovnik, & Prasad, 2007). Heat-induced thylakoid membrane damage is greatly associated with chlorophyll loss (Ristic et al., 2007). Variability is seen in wheat genotypes in terms of retention of chlorophyll during the stress due to high temperature (Ibrahim & Quick, 2001). Stability of photosynthetic pigments can serve as an indicator of plant tolerance to abiotic stresses (Paul, Sharma, Kumar, Pandey, & Meena, 2017). It has been observed that the chloroplasts in the glumes remained more preserved (structurally) even at the late stages of grain filling (at 24 and 32 days after anthesis) (Kong et al., 2015). Chlorophyll in nonleaf organs (such as ear, stem, and leaf sheath) get reduced very gradually and thereby these organs keep on exhibiting certain degree of photosynthesis even during the late stages of grain filling (Wang et al., 2016). Work from our lab (unpublished) on 20 wheat genotypes grown in field under heat stress condition revealed that in the spikelets of the main ear (at the time of anthesis) chlorophyll a, chlorophyll b, and total chlorophylls ranged from 0.317 to 555.4 mg/g FW, 0.077 to 0.145 mg/g FW, and 0.400 to 0.700 mg/g FW, respectively.URL: https://www.sciencedirect.com/science/article/pii/B9780128160916000134Lalit M. Srivastava, in , 2002Carotenoids serve two major functions in higher plants. As accessory pigments, they absorb light in the UV-A/blue regions of the spectrum and pass the light energy to chlorophyll. They also protect the chlorophylls from destruction under high light intensities by dissipating the excess energy (they quench the triplet state of chlorophyll [3Chl] and scavenge for singlet oxygen [1O2], a reactive oxygen species that can cause peroxidation of membrane lipids). Three xanthophylls, zeaxanthin, antheraxanthin, and violaxanthin, are the principal xanthophylls involved in photoprotection. These three xanthophylls occur in thylakoid membranes and participate in a cyclic reaction known as the xanthophyll cycle. In this cycle, zeaxanthin by two successive epoxidation reactions is converted to violaxanthin, and the latter by two successive de-epoxidations is converted back to zeaxanthin. Antheraxanthin is the intermediate in each case (Fig. 10-4). Zeaxanthin epoxidase (ZE) and violaxanthin de-epoxidase (VDE) are the enzymes that catalyze these interconversions. The activities of these enzymes are regulated by pH and light conditions. ZE activity is favored under limiting light; hence, under darkness or low light conditions, the accumulation of violaxanthin is favored. Excessive light has the effect of raising the proton concentration in the thylakoid lumen, thus increasing the pH gradient (δpH) across the thylakoid membrane. Under these conditions, the activity of VDE is favored and zeaxanthin accumulates. Zeaxanthin is the xanthophyll involved in dissipation of excess light energy.URL: https://www.sciencedirect.com/science/article/pii/B9780126605709501519L. Krienitz, in , 20096.3.5 Fucoxanthin and Its Application in Functional Foods 6.3.5 Fucoxanthin and Its Application in Functional FoodsFucoxanthin is a xanthophyll with the chemical formula C42H58O6. It is an accessory pigment in the chloroplasts of brown seaweeds, giving them a brown or olive-green color. Similar to phlorotannins, fucoxanthin also has good health benefit with potential applications in functional food products. It was found in metabolic and nutritional studies on rats and mice that fucoxanthin can promote fat burning within the fat cells in white adipose tissue by increasing the expression of thermogenin (https://en.wikipedia.org/wiki/Fucoxanthin; Maeda et al., 2005). In a double-blind placebo-controlled human study of females with liver disease, it was found that supplementation with seaweed extract containing fucoxanthin in combination with pomegranate seed oil showed an average 4.9 kg weight loss in obese women over a 16-week period (https://en.wikipedia.org/wiki/Fucoxanthin; Abidov et al., 2010). Fucoxanthin also has an effect on oxidative stress, oxidative stress-related diseases, and cancers. Many studies show that it aids in antiproliferation, cell cycle arrest, apoptosis induction, and suppression of angiogenesis, which are important for cancer prevention (Thamaraiselvan et al., 2013). It was shown that fucoxanthin has an inhibitory effect on invasiveness of cancer cells through suppressing the expression of gelatinolytic enzyme MMP-9. In addition, it was also found that fucoxanthin suppressed the motility of melanoma cells (https://en.wikipedia.org/wiki/Fucoxanthin; Chung et al., 2013).URL: https://www.sciencedirect.com/science/article/pii/B9780128133125000066CAROL M. LALLI, TIMOTHY R. PARSONS, in , 19973.2 PHOTOSYNTHESIS AND PRIMARY PRODUCTION 3.2 PHOTOSYNTHESIS AND PRIMARY PRODUCTIONPhytoplankton are the dominant primary producers of the pelagic realm converting inorganic materials (e.g. nitrate, phosphate) into new organic compounds (e.g. lipids, proteins) by the process of photosynthesis and thereby starting the marine food chain. The amount of plant tissue build up by photosynthesis over time is generally referred to as primary production, so called because photosynthetic production is the basis of most of marine production. As we will see later in Sections 5.5 and 8.9, there are other types of primary production that are carried out by bacteria capable of building organic materials through chemosynthetic mechanisms, but these are of minor importance in the oceans as a whole.Although a number of steps are involved, the chemical reactions for photosynthesis can be very generally summarized as:photosynthesis(requiring sunlight)6CO2carbon dioxide+6H2Owater⇌C6H12O6carbohydrate+6O2oxygenrespiration(requiring metabolic energy)Carbon dioxide utilized by the algae can be free dissolved CO2, or CO2 bound as bicarbonate or carbonate ions (see also Section 5.5.2). The total carbon dioxide (all three forms) is about 90 mg CO2 l–1 in oceanic waters, and this concentration is sufficiently high so that it does not limit the amount of photosynthesis by phytoplankton. This type of production, involving a reduction of carbon dioxide to produce high-energy organic substances, is also called autotrophic production; autotrophic organisms do not require organic materials as an energy source. Note that this process not only results in the production of plant carbohydrate, but it also produces free oxygen (which is derived from the water molecule, not from the carbon dioxide). The reverse process is respiration, in which there is an oxidative reaction that breaks the high-energy bonds of the carbohydrates and thus releases energy needed for metabolism. All organisms, including plants, carry out respiration. Whereas photosynthesis can proceed only during periods of daylight, respiration is carried out during both light and dark periods.Solar energy is used to drive the process of photosynthesis, and the conversion of radiant energy to chemical energy depends upon special photosynthetic pigments that are usually contained in chloroplasts of the algae. The dominant pigment is chlorophyll a, but chlorophylls b, c, and d plus accessory pigments (carotenes, xanthophylls, and phycobilins) are also present in many species and some of these pigments can also be involved in this conversion. All of these photosynthetically active pigments absorb light of wavelengths within the range of about 400–700 nm (PAR), but each shows a different absorption spectrum. Figure 3.4a gives the absorption spectrum of chlorophyll a, the most commonly occurring pigment; maximum absorption takes place in the red (650–700 nm) and blue-violet (450 nm) range. Figure 3.4b shows the absorption spectra of several accessory pigments. It is often these accessory pigments that dominate over the green colour of chlorophyll, and therefore many phytoplankton appear to be brown, golden, or even red in colour.Figure 3.4. (a) The absorption spectrum of chlorophyll a.(b) The absorption spectra of the accessory pigments fucoxanthin (a xanthophyll) and phycocyanin and phycoerythrin (phycobilins).QUESTION 3.2 Some planktonic (and benthic) algae contain large amounts of accessory pigments as well as chlorophyll. Refer to Figures 3.4a. b and Figure 2.4 and suggest how these pigments may be ecologically important for the algae concerned.When chlorophyll or other photosynthetically active pigments absorb light, the electrons in the pigments molecule acquire a higher energy level. This energy in the electrons is then transferred in a series of reactions in which ADP (adenosine diphosphate) is changed to higher energy ATP (adenosine triphosphate), and a compound called nicotinamide adenine dinucleotide phosphate (or NADPH2) is formed. These reactions, which are entirely dependent on light energy and involve the conversion of radiant energy to chemical energy, are called the light reactions of photosynthesis.The light reactions are inextricably linked with a series of reactions that do not require light and which are referred to as the dark reactions of photosynthesis. They involve the reduction of CO2 by NADPH2 and require the chemical energy of ATP to produce the end products of high-energy carbohydrates (usually polysaccharides) and other organic compounds such as lipids. Additionally, the reduction of nitrate (NO3–) yields amino acids and proteins.Note that in the reactions of photosynthesis, compounds are formed that contain nitrogen and phosphorus as well as the elements supplied by carbon dioxide and water. As with all plants, phytoplankton have absolute minimum requirements for these elements. Nitrogen is usually taken up by the phytoplankton cell in the form of dissolved nitrate, nitrite or ammonia; phosphorus is normally taken up in dissolved inorganic form (orthophosphate ions), or sometimes as dissolved organic phosphorus. Other elements may be required as well. Dissolved silicon, for example, is an absolute requirement for diatoms in producing the frustule. In addition, vitamins and certain trace elements may also be required, with types and amounts depending upon the species of phytoplankton. When photosynthetic species require vitamins or other organic growth factors, the production is termed auxotrophic. In seawater, all of the compounds referred to here are present in relatively low concentrations that vary according to the rates of photosynthesis and respiration and other biological activities, such as excretion by animals or bacterial decomposition. Therefore the concentrations of these essential elements or substances may at times become so low as to limit the amount of primary production. These considerations are discussed in Section 3.4.3.2.1 METHODS OF MEASURING BIOMASS AND PRIMARY PRODUCTIVITYStanding stock refers to the number of organisms per unit area or per unit volume of water at the moment of sampling. For phytoplankton, this can be measured by microscopic cell counts of preserved phytoplankton filtered from seawater samples, and the standing stock is given in number of cells per volume of water. However, because phytoplankton vary greatly in size, total numbers are not as ecologically meaningful as estimates of their biomass. Biomass is defined as the total weight (total numbers × average weight) of all organisms in a given area or volume. It is possible to count numbers and measure volumes of phytoplankton electronically, and this method attempts to provide an estimate of phytoplankton biomass, although cell volume may not always accurately reflect cell weight. Biomass is then expressed as the total volume (total numbers × volumes = mm3) of phytoplankton cells per unit volume of water. The distinction between standing stock and biomass is not always made evident, however, and often the terms are used synonymously.Another laboratory method that attempts to estimate phytoplankton biomass determines the quantity of chlorophyll a in seawater. This method is often used because chlorophyll a is universally present in all species of phytoplankton, can be easily measured, and its relative abundance enables estimates to be made of the productive capacity of the phytoplankton community. A known volume of water is filtered, and plant pigments are extracted in acetone from the organisms retained on the filter. The concentration of chlorophyll a is then estimated by placing the sample in a fluorometer to measure fluorescence, or in a spectrophotometer which measures the extinction of different wavelengths in a beam of light shining through the sample. The biomass is expressed as the amount of chlorophyll a per volume of water, or as the amount contained in the water column under a square metre of water surface.However, the rate at which plant material is produced, or the primary productivity, is of more ecological interest than instantaneous measures of standing stock or biomass. The most popular method of measuring productivity in the sea is the 14C method. In this method, a small measured amount of radioactive bicarbonate (HCO3–) is added to two bottles of seawater containing phytoplankton. One bottle is exposed to light and permits photosynthesis and respiration; the other is shielded from all light so that only respiration takes place. The amount of radioactive carbon taken up per unit time is later measured on the phytoplankton when they are filtered out of the original samples. This radioactivity is measured using a scintillation counter, and primary productivity (in mg C m–3 h–1) is calculated from:(3.1)rate of production=(RL−RD)×WR×t(3.1)where R is the total radioactivity added to a sample, t is the number of hours of incubation, RL is the radioactive count in the ‘light’ bottle sample, and RD is the count of the ‘dark’ sample. W is the total weight of all forms of carbon dioxide in the sample (in mg C m–3), and this is determined independently, either by titration or from assuming a specific carbon dioxide content related to the salinity of the sample. The productivity is expressed as the amount (in mg) of carbon fixed in new organic material per volume of water (m–3) per unit time (h–1); it varies between zero and as much as about 80 mg C m–3 h–1. This method is applied to water samples taken from a series of depths. In order to calculate production throughout the euphotic zone and to facilitate comparisons, the results obtained at different depths may be integrated to give production in terms of the amount of carbon fixed in the water column under a square metre of surface per day (g C m–2 day–1). If the amount of carbon fixed per unit time is coupled with chlorophyll a measurements of biomass, one obtains a measure of growth rate in units of time (mg C per mg chlorophyll a per hour); this measure of productivity is sometimes called the assimilation index (see Table 3.2).Table 3.2. Representative values of Pmax and ΔP/ΔI. ΔP/ΔI is the initial slope of the curve in Figure 3.5 and is given in terms of productivity divided by solar radiation; Pmax is given as the maximum value of the assimilation index (see Section 3.2.1).Pmax (assimilation index) (mg C mg–1 Chl α h–1)Comment2–14General range2–3.5Low temperatures, 2–4°C6–10High temperatures, 8–18°C0.2–1.0Low nutrients (e.g. in the Kuroshio current)9–17High nutrients and high temperatures (e.g. in tropical coastal waters)ΔP/ΔI (initial slope) (mg C mg–1 Chl α h–1)/(μE m–2 s–1Comment0.01–0.02Temperate ocean0.005–0.01Subtropical waters0.02–0.06Picoplankton (< 1.0 μm)0.006–0.13 (annual average, 0.045)Annual range for temperate coastal watersThe carbon-14 method described above can be made very precise by careful experimental techniques but, at the same time, there is reason to question its accuracy. For example, the uptake in the dark bottle (Rd) is assumed to represent a blank with which to correct the uptake in the light bottle (RL). This assumes that, except for photosynthesis, the same biological activities go on in both the light and dark bottles; but this may not be quite true. Also, any soluble organic material that is lost by the phytoplankton (a process known as exudation) during the period of photosynthesis will not be measured as it is not retained during filtration. Therefore, although the l4C method is the most practical measurement of photosynthesis in the sea, it may sometimes lead to errors.Other techniques have been developed for measuring chlorophyll concentration and thus relative phytoplankton abundance over large expanses of sea. A fluorometer that produces a certain wavelength of ultraviolet light will cause chlorophyll to emit a red fluorescence, and this device can then estimate the amount of chlorophyll in a volume of water. The method is very sensitive, and a fluorometer towed from a research vessel (see Figure 4.2) can rapidly record changes in chlorophyll concentration over large distances of sea surface. Remote sensing by aircraft or satellites provides even broader spatial coverage of phytoplankton abundance. This technique is based on the fact that the radiance reflected from the sea surface in the visible (or PAR) spectrum (400–700 nm) is related to the concentration of chlorophyll. Because chlorophyll is green, and water colour changes from blue to green as chlorophyll concentration increases, the relative colour differences can be used as a measure of chlorophyll concentration (see Colour Plate 8). Satellite measurements are not as sensitive as others and have restrictions of limited depth penetration, but they provide useful patterns of relative plant production on a global scale.URL: https://www.sciencedirect.com/science/article/pii/B9780750633840500591W.F. Vincent, in , 20091 The Photosystem 1 The PhotosystemThe chromist lineages absorb wavelengths over a broad light spectrum. Plastids of redalgae possess chlorophyll a and the accessory pigments β-carotene and phycobilins, with which they absorb wavelengths from 480−580 nm; green algal plastids have chlorophyll a and b and a set of carotenoids, with which they catch a more energetic part of the spectrum (400−520 nm). This would render red algae suited for coastal environments, whereas green algae are better at living in the deep blue waters of the open ocean. Peculiarly, prasinophytes, which belong to the green algae, dominate modern coastal picoplankton communities (Medlin et al. 2006). Perhaps they occupy a size niche where diatoms cannot thrive. The chromist chloroplasts lost phycobilins but retained chlorophyll a and β-carotene and acquired various forms of chlorophyll c and fucoxanthin (see Jeffrey and Wright 2005). These pigments permitted light, harvesting outside the absorption spectrum of green and red algae (400−580 nm).The xanthophylls diadinoxanthin and diatoxanthin protect the photosystem of the chromist lineages from harmful effects of light saturation (Falkowski and Raven 2007). With these compounds, heterokontophytes, haptophytes, and most dinoflagellates can photoacclimate their light capturing system rapidly to the quantity of the incoming light, especially from low light conditions into high light. Diadinoxanthin, the inactive precursor of diatoxanthin, is always in stock and can be transferred into the active compound within a minute when exposed to high light stress. Diatoxanthin dissipates energy by means of nonphotochemical quenching (Lavaud et al. 2004). The reverse reaction back to diadinoxanthin is much slower. The content of chlorophyll and accessory light capturing pigments can also be fine-tuned to the amount of incoming light, but these responses are much slower.URL: https://www.sciencedirect.com/science/article/pii/B9780123705181500126JournalJournalJournalJournalWe use cookies to help provide and enhance our service and tailor content and ads. By continuing you agree to the .Copyright © 2022 Elsevier B.V. or its licensors or contributors. ScienceDirect ® is a registered trademark of Elsevier B.V.ScienceDirect ® is a registered trademark of Elsevier B.V.

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study.com

https://study.com/learn/lesson/chlorophyll-b-pigment-photosynthesis.html

Jan 10, 2022 . Accessory Pigments in Photosynthesis. Because a plant needs to absorb light at different wavelengths, accessory pigments play a key role in assisting chlorophyll a with the absorption of light.The ...

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easierwithpractice.com

https://easierwithpractice.com/why-are-accessory-pigments-important-for-photosynthesis/

Mar 23, 2021 . Accessory pigments are light absorbing compounds found in photosynthetic organisms that function in combination with chlorophyll a. They have other types of this pigment, such as chlorophyll b in green algae and higher plant antennae, while other algae may contain chlorophyll c or d. How the Photooxidation can be prevented?

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biologywise.com

https://biologywise.com/accessory-pigments

Accessory pigments play an important role in the process of photosynthesis. This article gives you more information about them. The compounds present in plants that, in a way, assist in the absorption of light during the process of photosynthesis, are accessory pigments. As their name suggests, they act as helpers or assist chlorophyll in absorption of light.

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naipublishers.com

https://naipublishers.com/clusters-of-chlorophyll-and-accessory-pigments-are-called/

Oct 09, 2021 . The accessory pigments are arranged in numerous light-harvesting complexes that totally surround the reaction center. The 26-kd subunit that light-harvesting complicated II (LHC-II) is the many abundant membrane protein in chloroplasts. This subunit binds 7 chlorophyll a molecules, six chlorophyll b molecules, and two carotinoid molecules.

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researchgate.net

https://www.researchgate.net/publication/200146938_Accessory_Pigments_versus_Chlorophyll_a_Concentrations_within_the_Euphotic_Zone_A_Ubiquitous_Relationship

Ratios of accessory pigments (AP) to total chlorophyll a (TChl a) varied according to phytoplankton community composition, with polar phytoplankton (cold …

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study.com

https://study.com/academy/lesson/accessory-pigments-in-photosynthesis-definition-function-quiz.html

All of these various forms of chlorophyll, except chlorophyll-a, are considered accessory pigments because they, unlike chlorophyll-a, can't actually convert photons of …

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weebly.com

https://xopuwofotore.weebly.com/uploads/1/3/1/8/131871456/minuxavobemewalomuro.pdf

Accessory pigments, both additional chlorophylls as well as other classes of molecules, are closely associated with reaction centers. These pigments absorb light and funnel the energy to the reaction center for conversion into chemical forms. Indeed, experiments in 1932 by Robert Emerson and William Arnold on Chlorella cells

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easierwithpractice.com

https://easierwithpractice.com/what-wavelengths-do-accessory-pigments-absorb/

Dec 05, 2019 . Chlorophyll a is the core pigment that absorbs sunlight for light dependent photosynthesis. Accessory pigments such as: cholorphyll b, carotenoids, xanthophylls and anthocyanins lend a hand to chlorophyll a molecules by absorbing a …

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study.com

https://study.com/academy/practice/quiz-worksheet-chlorophyll-and-photosynthesis.html

Chlorophyll is reduced by red wavelengths Accessory pigments reduce chlorophyll Accessory pigments convert chlorophyll into energy Chlorophyll absorbs all visible light energy 2. …

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coursehero.com

https://www.coursehero.com/file/p1fl6fko/What-are-some-of-the-accessory-pigments-in-photosynthesis-and-what-do-they-do/

Only chlorophyll a participates directly in the light reactions , but accessory photosynthetic pigments absorb light and transfer energy to chlorophyll a . Chlorophyll b : with a slightly different structure than chlorophyll a , has a slightly different absorption spectrum and funnels the energy from these wavelengths to chlorophyll a . Carotenoids : can funnel the energy …

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theknowledgeburrow.com

https://theknowledgeburrow.com/why-do-shade-adapted-leaves-produce-more-chlorophyll/

May 07, 2021 . Chloroplasts Capture Sunlight When light strikes chlorophyll (or an accessory pigment) within the chloroplast, it energizes electrons within that molecule. These electrons jump up to higher energy levels; they have absorbed or captured, and now carry, that energy.

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nih.gov

https://pubmed.ncbi.nlm.nih.gov/28850868/

Abstract. Nitrogen starvation has been stated to reduce chlorophyll a and accessory pigments, decrease photosynthetic efficiency, as well as modify chloroplast thylakoid membranes. However, the impact of N-deficiency on light-dependent reactions of … Author: M.D. Cetner, H.M. Kalaji, V. Goltsev, V. Aleksandrov, K. Kowalczyk, W. Borucki, A. Jajoo Publish Year: 2017

Author: M.D. Cetner, H.M. Kalaji, V. Goltsev, V. Aleksandrov, K. Kowalczyk, W. Borucki, A. Jajoo

Publish Year: 2017

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quizlet.com

https://quizlet.com/6927307/accessory-pigments-flash-cards/

Pigment molecule that absorbs light and in visible region. Chlorophyll absorbs blue and red light-reflects green light (that's why grass is green) Photosystem ONE (PSI) makes NADPH-transports p+ and e- Photosystem TWO (PS2) absorbs light (chlorophyll) Photolysis split water with light energy Bundle Sheath Cells well developed PEP Carboxylase

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runyoncanyon-losangeles.com

https://runyoncanyon-losangeles.com/blog/what-is-the-absorption-spectrum-of-chlorophyll-a-and-b/

Chlorophyll A Chlorophyll B; It is the principal pigment involved in photosynthesis. It is an accessory pigment that helps in photosynthesis. All plants, algae, bacteria, cyanobacteria, and phototrophs contain chlorophyll a.

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us-ocb.org

https://us-ocb.org/wp-content/uploads/sites/43/2018/04/Rivero-Calle.pdf

2. Ratio of accessory pigments to chl a Deciphering phytoplankton community dynamics from HPLC pigment variability Sara Rivero-Calle, Naomi M. Levine University of Southern California. Los Angeles, CA Background Phytoplankton pigments can provide insight into phytoplankton size classes, functional groups and taxonomy. High Performance Liquid

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https://lisbdnet.com/why-do-plants-have-these-other-pigments-besides-chlorophyll/

Dec 06, 2021 . What other pigments are in plants besides chlorophyll? Chlorophyll a is the core pigment that absorbs sunlight for light dependent photosynthesis. Accessory pigments such as: cholorphyll b, carotenoids, xanthophylls and anthocyanins lend a hand to chlorophyll a molecules by absorbing a broader spectrum of light waves.

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