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Ergastic Substance
Ergastic substances are non- protoplasmic materials found in cells. The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell. The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins, resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage. Ergastic substances may appear in the protoplasm, in vacuoles, or in the cell wall. Carbohydrates Reserve carbohydrate of plants are the derivatives of the end products of photosynthesis. Cellulose and starch are the main ergastic substances of plant cells. Cellulose is the chief component of the cell wall, and starch occurs as a reserve material in the protoplasm. Starch, as starch grains, arise almost exclusively in plastids, especially leucoplasts and amyloplasts. Proteins Although proteins are the main component of living protopl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoplasmic
Protoplasm (; ) is the part of a cell that is surrounded by a plasma membrane. It is a mixture of small molecules such as ions, monosaccharides, amino acids, and macromolecules such as proteins, polysaccharides, lipids, etc. In some definitions, it is a general term for the cytoplasm (e.g., Mohl, 1846), but for others, it also includes the nucleoplasm (e.g., Strasburger, 1882). For Sharp (1921), "According to the older usage the extra-nuclear portion of the protoplast 'the entire cell, excluding the cell wall''was called "protoplasm," but the nucleus also is composed of protoplasm, or living substance in its broader sense. The current consensus is to avoid this ambiguity by employing Strasburger's (1882) terms cytoplasm Kölliker (1863), originally as synonym for protoplasm''and nucleoplasm 'term coined by Edouard Van Beneden">van Beneden (1875), or karyoplasm, used by Walther Flemming">Flemming (1878)'']." The cytoplasm definition of Strasburger excluded the plastids (''Chroma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids are broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/ unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Druse (botany)
A druse is a group of crystals of calcium oxalate, silicates, or carbonates present in plants, and are thought to be a defense against herbivory due to their toxicity. Calcium oxalate (Ca(COO)2, CaOx) crystals are found in algae, angiosperms and gymnosperms in more than 215 families. These plants accumulate oxalate in the range of 3–80% (w/w) of their dry weight through a biomineralization process in a variety of shapes. ''Araceae'' have numerous druses, multi-crystal druses and needle-shaped raphide crystals of CaOx present in the tissue. Druses are also found in leaves and bud scales of ''Prunus'', ''Rosa'', ''Allium'', ''Vitis'', '' Morus'' and ''Phaseolus''. Formation A number of biochemical pathways for calcium oxalate biomineralization in plants have been proposed. Among these is the cleavage of isocitrate, the hydrolysis of oxaloacetate, glycolate/glyoxylate oxidation, and/or oxidative cleavage of L-ascorbic acid. The cleavage of ascorbic acid appears to be the most s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taro
Taro (; ''Colocasia esculenta'') is a root vegetable. It is the most widely cultivated species of several plants in the family Araceae that are used as vegetables for their corms, leaves, stems and Petiole (botany), petioles. Taro corms are a food staple in Culture of Africa, African, Oceania, Oceanic, East Asian, Southeast Asian and South Asian cultures (similar to Yam (vegetable), yams). Taro is believed to be one of the earliest cultivated plants. Common names The English term '':wikt:taro#English, taro'' was :wikt:taro#Maori, borrowed from the Māori language when James Cook, Captain Cook first observed ''Colocasia'' plantations in New Zealand in 1769. The form ''taro'' or ''talo'' is widespread among Polynesian languages:*''talo'': taro (''Colocasia esculenta'') – entry in the ''Polynesian Lexicon Project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dieffenbachia
''Dieffenbachia'' , commonly known as dumb cane or leopard lily, is a genus of tropical flowering plants in the family (biology), family Araceae. It is native to the New World Tropics from Mexico and the West Indies south to Argentina. Some species are widely cultivated as ornamental plants, especially as houseplants, and have become naturalized on a few tropical islands. ''Dieffenbachia'' is a perennial plant, perennial herbaceous plant with straight stem, simple and alternate leaves containing white spots and flecks, making it attractive as indoor foliage. Species in this genus are popular as houseplants because of their tolerance of shade. The English names, dumb cane and mother-in-law's tongue (also used for ''Sansevieria'' species) refer to the poisoning effect of raphides, which can cause temporary inability to speak. ''Dieffenbachia'' was named by Heinrich Wilhelm Schott, director of the Botanical Gardens in Vienna, to honor his head gardener Joseph Dieffenbach (1790–186 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raphides
Raphides ( ; singular ''raphide'' or ''raphis'') are needle-shaped crystals of calcium oxalate monohydrate (prismatic monoclinic crystals) or calcium carbonate as aragonite ( dipyramidal orthorhombic crystals), found in more than 200 families of plants. Both ends are needle-like, but raphides tend to be blunt at one end and sharp at the other. Calcium oxalate in plants Many plants accumulate calcium oxalate crystals in response to surplus calcium, which is found throughout the natural environment. The crystals are produced in a variety of shapes. The crystal morphology depends on the taxonomic group of the plant. In one study of over 100 species, it was found that calcium oxalate accounted for 6.3% of plant dry weight. Crystal morphology and the distribution of raphides (in roots or leaves or tubers etc.) is similar in some taxa but different in others leaving possible opportunities for plant key characteristics and systematic identification; mucilage in raphide containing c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product. Examples include fused quartz, fumed silica, opal, and aerogels. It is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries. All forms are white or colorless, although impure samples can be colored. Silicon dioxide is a common fundamental constituent of glass. Structure In the majority of silicon dioxides, the silicon atom shows Tetrahedral molecular geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossils of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name comes from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceuticals for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The Geology, geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock (geology), rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate (geology), aggregate of two or more different types of minerals, spaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutin
Cutin is one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants, the other being cutan. It is an insoluble substance with waterproof quality. Cutin also harbors cuticular waxes, which assist in cuticle structure. Cutan, the other major cuticle polymer, is much more readily preserved in fossil records. Cutin consists of omega hydroxy acids and their derivatives, which are interlinked via ester bonds, forming a polyester polymer of indeterminate size. There are two major monomer families of cutin, the C16 and C18 families. The C16 family consists mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family consists mainly of 18-hydroxy oleic acid Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish due to the presence of impurities. In chemical terms, oleic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suberin
Suberin is a lipophilic, complex polyester biopolymer found in plants. It is composed of long-chain fatty acids (called suberin acids) and glycerol. Suberin is interconnected with cutin and lignin and forms a protective barrier in the epidermal and peridermal cell walls of higher plants. Suberin and lignin are considered covalently linked to lipids and carbohydrates, respectively. Lignin is again covalently linked to suberin, and to a lesser extent to cutin, thus construdting a complex macromolecular matrix. Suberin is a major constituent of cork, and is named after the cork oak, '' Quercus suber''. Its main function is as a barrier to movement of water and solutes. Anatomy and physiology Suberin is highly hydrophobic and a somewhat 'rubbery' material. In roots, suberin is deposited in the radial and transverse/tangential cell walls of the endodermal cells. This structure, known as the Casparian strip or Casparian band, functions to prevent water and nutrients taken up by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluten
Gluten is a structural protein naturally found in certain Cereal, cereal grains. The term ''gluten'' usually refers to the elastic network of a wheat grain's proteins, gliadin and glutenin primarily, that forms readily with the addition of water and often kneading in the case of bread dough. The types of grains that contain gluten include all species of wheat (common wheat, durum, spelt, Khorasan wheat, khorasan, emmer, and Einkorn wheat, einkorn), and barley, rye, and some cultivars of oat; moreover, cross hybrids of any of these cereal grains also contain gluten, e.g. triticale. Gluten makes up 75–85% of the total protein in Common wheat, bread wheat. Glutens, especially Triticeae glutens, have unique viscoelasticity, viscoelastic and Adhesion, adhesive properties, which give dough its elasticity, helping it Proofing (baking technique), rise and keep its shape and often leaving the final product with a chewy texture. These properties, and its relatively low cost, make gluten v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
