Ethylene biosynthesis and role in plants
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Ethylene was first observed in the 19th century to cause trees near street lamps to defoliate more than others. In the early 20th century, it was identified as a natural product in plants and shown to have dramatic effects, leading to its classification as a plant hormone. Ethylene is produced in many plant tissues and is highest in senescing and ripening tissues. It is a simple gas that can easily diffuse within and out of plant tissues and is biologically active at very low concentrations. Ethylene is synthesized from methionine and plays a key role in processes like fruit ripening and leaf abscission.
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Ethylene
This document discusses ethylene, a plant hormone that plays an important role in fruit ripening. It describes how ethylene is produced through the methionine pathway and triggers climacteric fruit to ripen. Factors like stage of development, auxins, injuries and temperature can influence ethylene production. The document also categorizes fruits based on their ethylene production rates and discusses how ethylene can be removed or its action inhibited during storage to extend shelf life.
Molecular And Biochemical Steps In Biosynthesis Of Ethylene In Plant
Ethylene is a plant hormone that affects processes like fruit ripening, leaf abscission, and stress responses. It is synthesized from the amino acid methionine through a pathway involving S-adenosyl methionine and 1-aminocyclopropane-1-carboxylic acid. Ethylene production is induced by stresses and during fruit ripening. Ethylene is a gas that diffuses through plant tissues and elicits responses by altering membrane permeability and gene expression. It regulates auxin transport and metabolism to influence developmental processes.
Fruit ripening
Ripening is a process in fruits that makes them acceptable for consumption by converting starch to sugar, changing color, and developing full flavor and aroma. Ripening is triggered by the plant hormone ethylene in climacteric fruits like bananas and tomatoes, causing a spike in respiration. In commercial operations, controlled ethylene exposure is used to induce ripening. Treatment with 1-methylcyclopropene binds ethylene receptors and inhibits ripening, allowing longer storage of climacteric fruits.
Ethylene
Ethylene is a plant hormone that regulates many processes in plants including fruit ripening, flower and leaf senescence, and stress responses. It was discovered in 1864 that gas leaks caused abnormal plant growth and was later identified as the hydrocarbon ethylene. Ethylene is produced from methionine through various intermediates and binds to receptors in plants to trigger gene expression changes and physiological responses. Some key effects of ethylene include stimulating fruit ripening, inducing leaf and flower abscission, breaking seed and bud dormancy, and causing the "triple response" in seedlings.
Role of ethylene in fruit ripening
The document discusses mechanisms of fruit ripening and methods used to induce or delay ripening. It covers three main changes during ripening: structural, physical and biochemical. Common ripening induction methods like smoking and use of ripening agents like calcium carbide and ethephon are described. Optimal conditions for controlled ripening using ethylene gas are provided for different fruits. Methods to manage ethylene concentration and absorb or inhibit ethylene using products like 1-MCP are also summarized. The effects of ethephon and ethylene gas on total soluble solids during pear ripening are shown. In conclusion, ethylene absorbents and inhibitors are effective for delayed ripening while ethephon is recommended over calcium carbide for safe commercial fruit ripening
Biochemistry of fruit ripening
Ripening definition, Biochemistry of fruit ripening, Cell wall degradation, Modifications of cell wall components, starch into simple sugars, degradation of chlorophyll content
Cytokinin
This document discusses cytokinins, a class of plant growth hormones. It begins by defining cytokinins and their role in promoting cell division. It then discusses the discovery of cytokinins in 1954 using DNA from herring sperm. The document outlines that cytokinins are synthesized primarily in root tips and occur throughout actively dividing plant tissues. It describes the chemical structure of major cytokinins like benzyladenine, kinetin, and zeatin which are adenine derivatives. Finally, it lists several physiological roles of cytokinins like stimulating cell division and elongation, delaying senescence, promoting flowering, and breaking seed dormancy.
Mechanism of Fruit ripening
Changes during ripening, mechanism behind the changes, Role of ethylene in ripening
contact: dhota3@gmail.com
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Ethylene
This document discusses ethylene, a plant hormone that plays an important role in fruit ripening. It describes how ethylene is produced through the methionine pathway and triggers climacteric fruit to ripen. Factors like stage of development, auxins, injuries and temperature can influence ethylene production. The document also categorizes fruits based on their ethylene production rates and discusses how ethylene can be removed or its action inhibited during storage to extend shelf life.
Molecular And Biochemical Steps In Biosynthesis Of Ethylene In Plant
Ethylene is a plant hormone that affects processes like fruit ripening, leaf abscission, and stress responses. It is synthesized from the amino acid methionine through a pathway involving S-adenosyl methionine and 1-aminocyclopropane-1-carboxylic acid. Ethylene production is induced by stresses and during fruit ripening. Ethylene is a gas that diffuses through plant tissues and elicits responses by altering membrane permeability and gene expression. It regulates auxin transport and metabolism to influence developmental processes.
Fruit ripening
Ripening is a process in fruits that makes them acceptable for consumption by converting starch to sugar, changing color, and developing full flavor and aroma. Ripening is triggered by the plant hormone ethylene in climacteric fruits like bananas and tomatoes, causing a spike in respiration. In commercial operations, controlled ethylene exposure is used to induce ripening. Treatment with 1-methylcyclopropene binds ethylene receptors and inhibits ripening, allowing longer storage of climacteric fruits.
Ethylene
Ethylene is a plant hormone that regulates many processes in plants including fruit ripening, flower and leaf senescence, and stress responses. It was discovered in 1864 that gas leaks caused abnormal plant growth and was later identified as the hydrocarbon ethylene. Ethylene is produced from methionine through various intermediates and binds to receptors in plants to trigger gene expression changes and physiological responses. Some key effects of ethylene include stimulating fruit ripening, inducing leaf and flower abscission, breaking seed and bud dormancy, and causing the "triple response" in seedlings.
Role of ethylene in fruit ripening
The document discusses mechanisms of fruit ripening and methods used to induce or delay ripening. It covers three main changes during ripening: structural, physical and biochemical. Common ripening induction methods like smoking and use of ripening agents like calcium carbide and ethephon are described. Optimal conditions for controlled ripening using ethylene gas are provided for different fruits. Methods to manage ethylene concentration and absorb or inhibit ethylene using products like 1-MCP are also summarized. The effects of ethephon and ethylene gas on total soluble solids during pear ripening are shown. In conclusion, ethylene absorbents and inhibitors are effective for delayed ripening while ethephon is recommended over calcium carbide for safe commercial fruit ripening
Biochemistry of fruit ripening
Ripening definition, Biochemistry of fruit ripening, Cell wall degradation, Modifications of cell wall components, starch into simple sugars, degradation of chlorophyll content
Cytokinin
This document discusses cytokinins, a class of plant growth hormones. It begins by defining cytokinins and their role in promoting cell division. It then discusses the discovery of cytokinins in 1954 using DNA from herring sperm. The document outlines that cytokinins are synthesized primarily in root tips and occur throughout actively dividing plant tissues. It describes the chemical structure of major cytokinins like benzyladenine, kinetin, and zeatin which are adenine derivatives. Finally, it lists several physiological roles of cytokinins like stimulating cell division and elongation, delaying senescence, promoting flowering, and breaking seed dormancy.
Mechanism of Fruit ripening
Changes during ripening, mechanism behind the changes, Role of ethylene in ripening
contact: dhota3@gmail.com
Cytokinin
Cytokinins are plant hormones that promote cell division and play important roles in plant growth and development. They are synthesized primarily in root tips and transported upward through the xylem. Cytokinin biosynthesis involves the enzyme adenylate isopentenyltransferase, which catalyzes the first reaction. Cytokinins signal through a phosphorelay pathway involving histidine kinase receptors, Arabidopsis response regulators, and feedback loops to regulate gene expression and cellular responses. Cytokinins promote cell division, axillary bud outgrowth, seed development, delay senescence, and stimulate morphogenesis and shoot initiation.
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This document provides information about abscisic acid (ABA), including its chemical structure, biosynthesis, roles in plants, and research findings. Some key points:
- ABA is a plant hormone involved in processes like seed dormancy, stomatal closure, and leaf senescence. It has a cis-trans isomer structure and exists primarily in the cis form.
- ABA is biosynthesized through direct and indirect pathways, with the indirect pathway being more common in plants. This pathway involves carotenoid precursors that are cleaved to form ABA.
- Research has examined ABA's role in regulating strawberry fruit development and ripening. Studies show ABA levels change over fruit growth stages and that
Ethylene
1. Ethylene is a plant hormone that influences many aspects of plant growth and development. It plays an important role in fruit ripening.
2. Ethylene's effects on plants were observed as far back as ancient Egypt, China, and India, where smoke or burning materials were used to stimulate ripening.
3. Ethylene is produced by plants, bacteria, and fungi. It is involved in processes like stimulating seed germination, root and shoot growth, flowering, leaf and fruit drop, and fruit ripening.
Cytokinins
The document discusses cytokinins, plant growth hormones that promote cell division. It describes the discovery of kinetin and zeatin as the first synthetic and natural cytokinins. The structure, biosynthesis from adenosine monophosphate, and mechanism of action via receptors are explained. Cytokinins function to promote cell division, enlargement, flowering, delay senescence, and break seed dormancy.
Abscission
Abscission is the process by which plant organs such as leaves, flowers, and fruits become detached from the plant in a controlled manner. It occurs through the formation of an abscission zone, a layer of weak-walled cells located at the base of the petiole or other structure. Abscission is controlled by the plant hormones auxin and ethylene, with decreasing auxin and increasing ethylene levels initiating cell wall degradation in the abscission zone. This allows separation of plant organs through a combination of enzymatic breakdown and mechanical forces. Abscission aids in shedding organs no longer needed by the plant and occurs in response to environmental and developmental signals.
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Abscisic acid is a plant growth harmone which is very important in the growth and development of plants.
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Ethylene and abscisic acid are important plant hormones. Ethylene is produced through the biosynthesis pathway of methionine to S-adenosylmethionine to 1-amino-cyclopropane-1-carboxylic acid to ethylene. Its mechanism of action includes effects on DNA, RNA, proteins and organelles. Abscisic acid was discovered in the 1960s and promotes dormancy, inhibits growth, and induces abscission. It is synthesized indirectly from carotenoids like violaxanthin and acts by inhibiting RNA and protein synthesis and altering membrane permeability.
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1. Cytokinins are plant hormones that promote cell division. The first was discovered in 1955 and is called kinetin, derived from degraded herring sperm DNA.
2. Cytokinins are synthesized primarily in root apical meristems but also other growing tissues. They move up through the xylem while auxin moves down.
3. In Arabidopsis, cytokinin signaling involves receptors that phosphorylate histidine phosphotransfer proteins, leading to phosphorylation of ARR transcription factors and expression of genes causing cytokinin responses.
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The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway.
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Biosynthesis of auxin[1]
This document summarizes information about the plant growth hormone auxin. It defines auxin as chemical substances that promote stem or root growth. The first known auxin is indole-3-acetic acid. There are two types of auxin: natural auxins produced by plants like IAA, and synthetic auxins created in labs. The document then describes the three step biosynthesis process of IAA from the amino acid tryptophan. Finally, it lists several physiological effects of auxins, including cell elongation, promotion of cell division, root growth, apical dominance, prevention of abscission, formation of seedless fruits, and regulation of plant growth movements.
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Auxins biosynthesis physiological role and mechanism
Auxins are plant hormones that regulate growth and development. The main auxin is indole-3-acetic acid (IAA) which is synthesized from the amino acid tryptophan through several pathways. IAA is transported from shoot tips to regions of elongation through active transport and influences growth through effects on cell wall plasticity and gene expression. Auxins have many physiological roles including stem elongation, apical dominance, root initiation, fruit development, and growth responses to light.
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Ethylene effect on fruits and vegetables - By Maha Hussien
Ethylene is a plant hormone that promotes ripening and aging. It is produced naturally by plants and through combustion. During the 19th century, it was observed that trees near street lamps with coal gas defoliated more, and ethylene in the coal gas was found to be responsible. Ethylene is derived from methionine and promotes processes like fruit ripening, leaf abscission, and seed germination. It is measured using gas chromatography and its signaling pathway involves binding to a copper-containing receptor protein that activates transcription factors when ethylene is present.
Ethylene
Ethylene is a plant hormone with the formula C2H4. It serves to stimulate or regulate fruit ripening, flower opening, and leaf shedding in plants. Ethylene was first discovered in 1864 to cause abnormal plant growth when released from street lamps. It has since been shown to induce various responses in plants like seed germination, fruit ripening, growth inhibition, abscission, flowering, and formation of adventitious roots and root hairs. Ethylene is biosynthesized from methionine and its effects are mediated by binding to a receptor and modulating gene expression.
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Five major classes of plant hormones are mentioned:
1. auxins,
2. cytokinins,
3. gibbereilins,
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Cytokinins are plant hormones that promote cell division and play important roles in plant growth and development. They are synthesized primarily in root tips and transported upward through the xylem. Cytokinin biosynthesis involves the enzyme adenylate isopentenyltransferase, which catalyzes the first reaction. Cytokinins signal through a phosphorelay pathway involving histidine kinase receptors, Arabidopsis response regulators, and feedback loops to regulate gene expression and cellular responses. Cytokinins promote cell division, axillary bud outgrowth, seed development, delay senescence, and stimulate morphogenesis and shoot initiation.
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This document provides information about abscisic acid (ABA), including its chemical structure, biosynthesis, roles in plants, and research findings. Some key points:
- ABA is a plant hormone involved in processes like seed dormancy, stomatal closure, and leaf senescence. It has a cis-trans isomer structure and exists primarily in the cis form.
- ABA is biosynthesized through direct and indirect pathways, with the indirect pathway being more common in plants. This pathway involves carotenoid precursors that are cleaved to form ABA.
- Research has examined ABA's role in regulating strawberry fruit development and ripening. Studies show ABA levels change over fruit growth stages and that
Ethylene
1. Ethylene is a plant hormone that influences many aspects of plant growth and development. It plays an important role in fruit ripening.
2. Ethylene's effects on plants were observed as far back as ancient Egypt, China, and India, where smoke or burning materials were used to stimulate ripening.
3. Ethylene is produced by plants, bacteria, and fungi. It is involved in processes like stimulating seed germination, root and shoot growth, flowering, leaf and fruit drop, and fruit ripening.
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The document discusses cytokinins, plant growth hormones that promote cell division. It describes the discovery of kinetin and zeatin as the first synthetic and natural cytokinins. The structure, biosynthesis from adenosine monophosphate, and mechanism of action via receptors are explained. Cytokinins function to promote cell division, enlargement, flowering, delay senescence, and break seed dormancy.
Abscission
Abscission is the process by which plant organs such as leaves, flowers, and fruits become detached from the plant in a controlled manner. It occurs through the formation of an abscission zone, a layer of weak-walled cells located at the base of the petiole or other structure. Abscission is controlled by the plant hormones auxin and ethylene, with decreasing auxin and increasing ethylene levels initiating cell wall degradation in the abscission zone. This allows separation of plant organs through a combination of enzymatic breakdown and mechanical forces. Abscission aids in shedding organs no longer needed by the plant and occurs in response to environmental and developmental signals.
Abscisic acid
Abscisic acid is a plant growth harmone which is very important in the growth and development of plants.
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Ethylene and abscisic acid are important plant hormones. Ethylene is produced through the biosynthesis pathway of methionine to S-adenosylmethionine to 1-amino-cyclopropane-1-carboxylic acid to ethylene. Its mechanism of action includes effects on DNA, RNA, proteins and organelles. Abscisic acid was discovered in the 1960s and promotes dormancy, inhibits growth, and induces abscission. It is synthesized indirectly from carotenoids like violaxanthin and acts by inhibiting RNA and protein synthesis and altering membrane permeability.
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Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation describes about ethylene with its biosynthesis, transport, pathways and physiological effects.
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1. Cytokinins are plant hormones that promote cell division. The first was discovered in 1955 and is called kinetin, derived from degraded herring sperm DNA.
2. Cytokinins are synthesized primarily in root apical meristems but also other growing tissues. They move up through the xylem while auxin moves down.
3. In Arabidopsis, cytokinin signaling involves receptors that phosphorylate histidine phosphotransfer proteins, leading to phosphorylation of ARR transcription factors and expression of genes causing cytokinin responses.
Vernalization
Vernalization is the process by which flowering is promoted through a cold treatment given to hydrated seeds or growing plants. Cold exposure cuts short the vegetative period, resulting in early flowering. Two main theories explain vernalization's mechanism: the phasic development theory proposes cold exposure accelerates plant development phases, while hormonal theories suggest cold induces a floral hormone called vernalin. Epigenetic changes in gene expression from cold exposure may also play a role, stably altering flowering gene expression even after the cold is removed. Vernalization has practical applications in agriculture by promoting early flowering, increasing disease resistance, and aiding crop improvement.
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The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway.
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This document summarizes information about the plant growth hormone auxin. It defines auxin as chemical substances that promote stem or root growth. The first known auxin is indole-3-acetic acid. There are two types of auxin: natural auxins produced by plants like IAA, and synthetic auxins created in labs. The document then describes the three step biosynthesis process of IAA from the amino acid tryptophan. Finally, it lists several physiological effects of auxins, including cell elongation, promotion of cell division, root growth, apical dominance, prevention of abscission, formation of seedless fruits, and regulation of plant growth movements.
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This document discusses the ripening processes of climacteric and non-climacteric fruits. It explains that climacteric fruits, such as bananas and mangoes, continue to ripen after harvesting through increased respiration and ethylene production. Non-climacteric fruits, like citrus, do not ripen further after harvesting. However, some fruits exhibit characteristics of both climacteric and non-climacteric ripening depending on cultivar. The document also outlines several techniques used to artificially induce or delay ripening, including the use of ethylene, calcium carbide, and other chemicals.
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Brassinosteroids
Brassinosteroids are a class of plant steroid hormones that were first discovered in rapeseed pollen in the 1960s. They influence many developmental processes similar to auxins. The most common brassinosteroid is brassinolide, which was first isolated from rapeseed in 1979. Brassinosteroids regulate processes like cell elongation, flowering, vascular development, photomorphogenesis, and stress tolerance. They are perceived by membrane receptors and signal through a phosphorylation cascade to regulate gene expression.
Auxins biosynthesis physiological role and mechanism
Auxins are plant hormones that regulate growth and development. The main auxin is indole-3-acetic acid (IAA) which is synthesized from the amino acid tryptophan through several pathways. IAA is transported from shoot tips to regions of elongation through active transport and influences growth through effects on cell wall plasticity and gene expression. Auxins have many physiological roles including stem elongation, apical dominance, root initiation, fruit development, and growth responses to light.
Role of Jasmonic acid in plant development and defense responses
Jasmonic acid is a plant hormone involved in plant defense and development. It is derived from α-linolenic acid through the octadecanoid pathway. Jasmonic acid regulates processes like photosynthesis, root and shoot growth, seed germination, development, and flowering. It triggers defense responses and is also involved in senescence, tendril coiling, flower development, and leaf abscission. Jasmonic acid induces tuberization in potato, trichome formation in tomato, and affects root growth, flower development, and senescence in plants. Research has shown it can inhibit aflatoxin production by fungi and impact insect pests like the brown planthopper.
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Ethylene is a plant hormone that promotes ripening and aging. It is produced naturally by plants and through combustion. During the 19th century, it was observed that trees near street lamps with coal gas defoliated more, and ethylene in the coal gas was found to be responsible. Ethylene is derived from methionine and promotes processes like fruit ripening, leaf abscission, and seed germination. It is measured using gas chromatography and its signaling pathway involves binding to a copper-containing receptor protein that activates transcription factors when ethylene is present.
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Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water, and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in two stages - the light-dependent reaction where sunlight is absorbed to make ATP and NADPH, and the light-independent reaction where carbon dioxide is fixed using ATP and NADPH to make glucose. Photosynthesis takes place in chloroplasts within plant cells and is essential for life on Earth as it produces the oxygen needed for respiration and food in the form of glucose.
Ecosystem and environmental hazards
The document discusses ecosystems, environmental hazards, and pollution. It defines ecosystems as communities of interacting species that exchange energy and matter. It describes ecosystem structure, including biotic and abiotic components, and functions such as productivity, decomposition, nutrient cycling, and energy flow. It also discusses different types of pollution like air, water, soil, and radiation pollution and their environmental impacts. In summary, the document provides an overview of ecosystems, hazards in the environment, and various types of pollution.
Plant hormone biosysnthesis and function amjad
This document summarizes the biosynthesis of several major plant hormones: auxins, gibberellins, cytokinins, abscisic acid, and ethylene. It describes the key discoveries in identifying each hormone, where they are produced in plants, their biosynthesis pathways, and main functions. For each hormone, it discusses the scientists who first discovered and isolated it, the tissues and organs where it is synthesized, and its role in processes like cell growth, flowering, dormancy, and stress responses.
Science
Van Helmont, Priestley, and Ingenhousz experiments revealed that plants grow using water and carbon dioxide, and produce oxygen. Photosynthesis uses light, water, carbon dioxide to produce oxygen, ATP, NADPH, and glucose through two stages - the light-dependent reactions in the thylakoid membranes that produce ATP and NADPH, and the light-independent Calvin cycle in the chloroplast stroma that uses ATP and NADPH to produce glucose.
alkaloids.pptx
Alkaloids- the term alkaloids are used to designate basic nitrogenous compounds of plant origin that are physiologically active. This ppt contains introduction of alkaloids, history, classification, property, function, uses of alkaloids, effects of alkaloids on human, extraction of alkaloids, biosynthesis of alkaloids, heterogeneous alkaloids, non heterogeneous alkaloids, solubility of alkaloids, chemical property of alkaloids, function of alkaloids in plant.
PHOTOSYNTHESIS
Photosynthesis is the process by which plants produce carbohydrates from carbon dioxide and water using energy from sunlight. It occurs in chloroplasts, which contain chlorophyll and are located in plant leaves. There are two phases - the light-dependent reaction uses solar energy to produce ATP and NADPH, while the light-independent Calvin cycle uses these products to fix carbon from carbon dioxide into glucose. Photosynthesis oxygenates the atmosphere and provides a crucial food source for the biological world.
Ch 13 photosynthesis in higher plants xi (1)
Photosynthesis is the primary source of food on Earth and releases oxygen into the atmosphere. Joseph Priestley and Jan Ingenhousz performed experiments in the 1700s that revealed plants require air and sunlight to grow. Ingenhousz showed oxygen bubbles form around green plant parts in sunlight. Later studies identified chloroplasts as the photosynthesis site in plant cells, with light and dark reactions taking place in the thylakoid membranes and stroma, respectively. The Calvin cycle was discovered to convert carbon dioxide into sugars using ATP and NADPH produced from the light reactions. Factors like light intensity, carbon dioxide levels, temperature and water availability can limit photosynthesis rates.
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Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
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∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
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±
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,
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km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
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Ca-rich population. Although such an object is too red for any low-
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CDM. Therefore unlike low-
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Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
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truly diverge from their low-
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counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
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一比一原版美国佩斯大学毕业证如何办理
原版一模一样【微信：741003700 】【美国佩斯大学毕业证成绩单】【微信：741003700 】学位证，留信认证（真实可查，永久存档）原件一模一样纸张工艺/offer、雅思、外壳等材料/诚信可靠,可直接看成品样本，帮您解决无法毕业带来的各种难题！外壳，原版制作，诚信可靠，可直接看成品样本。行业标杆！精益求精，诚心合作，真诚制作！多年品质 ,按需精细制作，24小时接单,全套进口原装设备。十五年致力于帮助留学生解决难题，包您满意。
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Neutralizing antibodies, pivotal in immune defense, specifically bind and inhibit viral pathogens, thereby playing a crucial role in protecting against and mitigating infectious diseases. In this slide, we will introduce what antibodies and neutralizing antibodies are, the production and regulation of neutralizing antibodies, their mechanisms of action, classification and applications, as well as the challenges they face.
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Quality assurance B.pharm 6th semester BP606T UNIT 5
Warehousing
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Embracing Deep Variability For Reproducibility and Replicability
Embracing Deep Variability For Reproducibility and ReplicabilityUniversity of Rennes, INSA Rennes, Inria/IRISA, CNRS
Embracing Deep Variability For Reproducibility and Replicability
Abstract: Reproducibility (aka determinism in some cases) constitutes a fundamental aspect in various fields of computer science, such as floating-point computations in numerical analysis and simulation, concurrency models in parallelism, reproducible builds for third parties integration and packaging, and containerization for execution environments. These concepts, while pervasive across diverse concerns, often exhibit intricate inter-dependencies, making it challenging to achieve a comprehensive understanding. In this short and vision paper we delve into the application of software engineering techniques, specifically variability management, to systematically identify and explicit points of variability that may give rise to reproducibility issues (eg language, libraries, compiler, virtual machine, OS, environment variables, etc). The primary objectives are: i) gaining insights into the variability layers and their possible interactions, ii) capturing and documenting configurations for the sake of reproducibility, and iii) exploring diverse configurations to replicate, and hence validate and ensure the robustness of results. By adopting these methodologies, we aim to address the complexities associated with reproducibility and replicability in modern software systems and environments, facilitating a more comprehensive and nuanced perspective on these critical aspects.
https://hal.science/hal-04582287
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Ethylene biosynthesis and role in plants
- 2. HISTORY OF ETHYLENE • During the 19th century, when coal gas was used as street illumination it was observed that trees in the vicinity of streetlamps defoliated more extensively than other trees. • In 1901, Dimitry Neljubov observed that dark grown pea seedlings in the laboratory exhibited symptoms that were later termed the triple response. • The first indication that ethylene is a natural product of plant tissues was published by H. H. Cousins in 1910. • In 1934, R. Gane and others identified ethylene chemically as a natural product of plant metabolism, and because of its dramatic effects on plant it was classified as a hormone.
- 3. OCCURANCE, DISTRIBUTION AND TRANSPORT OF EHYLENE IN PLANTS • Ethylene can easily be synthesized in all plant organs such as roots, stems, leaves, tubers, fruits and seeds. • It is highest in senescing tissues and ripening fruits. • Within the plant organs, ethylene formation is mainly located in peripheral tissues. • Ethylene is biologically active at low concentration (less than 1 ppm) • Ethylene can easily pass through plasmamembrane into the cell, easily diffuse within the plant, and flushed out of plant tissues through intercellular spaces
- 4. STRUCTURE AND BIOSYNTHESIS • Ethylene is the simplest olefin (mol. Wt. 28) . • It is lighter than water under physiological conditions and readily undergoes oxidation.
- 5. BIOSYNTHESIS
- 6. CONJUGATION AND CATABOLISM OF ETHYLENE • Not all the ACC found in the tissue is converted to ethylene. ACC can also be converted to a conjugated form ,N-malonyl ACC which accumulates in the tissue , primarily in the vacuole. • A minor conjugated form of ACC, 1-(y-L-glutamylamino) cyclopropane-1-carboxylic acid (GACC) has also been identified. • Carbon dioxide, ethylene oxide, ethylene glycol, and the glucose conjugate of ethylene glycol have been identified as metabolic breakdown products.
- 7. FACTORS PROMOTING ETHYLENE BIOSYNTHESIS • Fruit ripening. • Stress induced ethylene production,viz Drought, flooding, chilling, exposure to ozone, and mechanical wounding. • Auxin induced ethylene production. • Circadian regulation of ethylene production.
- 8. INHIBITORS OF ETHYLENE BIOSYNTHESIS AND ETHYLENE ACTION • Aminoethoxy-vinylglycine (AVG). • Aminooxyacetic acid (AOA). • Silver ions. • Carbon dioxide at high concentrations (5-10%). • trans-cyclooctene. • 1-Methylcyclopropene
- 9. PHYSIOLOGICAL EFFECTS OF ETHYLENE • Fruit ripening. • Plumular hook formation. • Triple response. • Formation of adventitious roots and root hairs. • Leaf epinasty. • Senescence. • Abscission of leaves.
- 10. MECHANISM OF ETHYLENE ACTION • Binding of ethylene to a receptor. • Activation of one or more signal transduction pathways. • Modulation of gene expression leading to cellular response.
- 11. MECHANISM
- 12. References • Taiz L.&Zeiger E.2010Plant Physiology 5th Ed. Sinauer Associates,inc. • JainVK.1974.fundamentals of Plant physiology 1st Ed.S.Chand.publishing
- 13. THANK YOU