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Mucigel
Mucigel is a slimy substance that covers the root cap of the roots of plants. It is a highly hydrated polysaccharide, most likely a pectin, which is secreted from the outermost (epidermal) cells of the rootcap. Mucigel is formed in the Golgi bodies of such cells, and is secreted through the process of exocytosis. The layer of microorganism-rich soil surrounding the mucigel is called the rhizosphere. Mucigel serves several functions, including: * Protection of rootcap; prevents desiccation * Lubrication of rootcap; allows root to more efficiently penetrate the soil * Creation of symbiotic environment for nitrogen fixing bacteria (i.e. diazotrophs) and fungi (which help with water absorption) * Provision of a 'diffusion bridge' between the fine root system and soil particles, which allows for a more efficient uptake of water and mineral nutrients by roots in dry soils. See also *Meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Cap
The root cap is a type of tissue at the tip of a plant root. It is also called calyptra. Root caps contain statocytes which are involved in gravity perception in plants. If the cap is carefully removed the root will grow randomly. The root cap protects the growing tip in plants. It secretes mucilage Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of m ... to ease the movement of the root through soil, and may also be involved in communication with the soil microbiota. The purpose of the root cap is to enable downward growth of the root, with the root cap covering the sensitive tissue in the root. Also, the root cap enables geoperception or gravitropism. This allows the plant to grow downwards (with gravity) or upwards (against gravity). The root cap is absent in some parasitic plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizosphere (ecology)
The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. Soil pores in the rhizosphere can contain many bacteria and other microorganisms that feed on sloughed-off plant cells, termed ''rhizodeposition'', and the proteins and sugars released by roots, termed root exudates. This symbiosis leads to more complex interactions, influencing plant growth and competition for resources. Much of the nutrient cycling and disease suppression by antibiotics required by plants, occurs immediately adjacent to roots due to root exudates and metabolic products of symbiotic and pathogenic communities of microorganisms. The rhizosphere also provides space to produce allelochemicals to control neighbours and relatives. The ''rhizoplane'' refers to the root surface including its associated soil particles which closely interact with each other. The plant-soil feedback loop and other phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazotrophs
Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia. A diazotroph is a microorganism that is able to grow without external sources of fixed nitrogen. Examples of organisms that do this are rhizobia and ''Frankia'' (in symbiosis) and ''Azospirillum''. All diazotrophs contain iron-molybdenum or iron-vanadium nitrogenase systems. Two of the most studied systems are those of ''Klebsiella pneumoniae'' and ''Azotobacter vinelandii''. These systems are studied because of their genetic tractability and their fast growth. Etymology The word diazotroph is derived from the words ''diazo'' ("di" = two + "azo" = nitrogen) meaning "dinitrogen (N2)" and ''troph'' meaning "pertaining to food or nourishment", in summary dinitrogen utilizing. The word ''azote'' means nitrogen in French and was named by French chemist and biologist Antoine Lavoisier, who saw it as the part of air which cannot sustain life. Types of diazotrophs Diaz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Fixing
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the Atmosphere of Earth, air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also Abiological nitrogen fixation, in industry. Atmospheric nitrogen is molecular Nitrogen#Allotropes, dinitrogen, a relatively nonreactive molecule that is Metabolism, metabolically useless to all but a few microorganisms. Biological nitrogen fixation or ''diazotrophy'' is an important microbials mediated process that converts dinitrogen (N2) gas to ammonia (NH3) using the nitrogenase protein complex (Nif). Nitrogen fixation is essential to life because fixed inorganic nitrogen compounds are required for the biosynthesis of all nitrogen-containing organic compounds, such as amino acids and proteins, nucleoside triphosphates and nucleic acids. As part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, must be of different species. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms". The term was subject to a century-long debate about whether it should specifically denote mutualism, as in lichens. Biologists have now abandoned that restriction. Symbiosis can be obligatory, which means that one or more of the symbionts depend on each other for survival, or facultative (optional), when they can generally live independently. Symbiosis is also classified by physical attachment. When symbionts form a single body it is called conjunctive symbiosis, while all other arrangements are called disjunctive symbiosis."symbiosis." Dorland's Illustrated Medical Dictionary. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desiccation
Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. Industry Desiccation is widely employed in the oil and gas industry. These materials are obtained in a hydrated state, but the water content leads to corrosion or is incompatible with downstream processing. Removal of water is achieved by cryogenic condensation, absorption into glycols, and absorption onto desiccants such as silica gel. Laboratory A desiccator is a heavy glass or plastic container, now somewhat antiquated, used in practical chemistry for drying or keeping small amounts of materials very dry. The material is placed on a shelf, and a drying agent or ''desiccant'', such as dry silica gel or anhydrous sodium hydroxide, is placed below the shelf. Often some sort of humidity indicator is included in the desiccator to show, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microorganism
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in older texts. The informal synonym ''microbe'' () comes from μικρός, mikrós, "small" and βίος, bíos, "life". is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from sixth century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Because mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the surface of the soil, but roots can also be aerial or aerating, that is, growing up above the ground or especially above water. Function The major functions of roots are absorption of water, plant nutrition and anchoring of the plant body to the ground. Anatomy Root morphology is divided into four zones: the root cap, the apical meristem, the elongation zone, and the hair. The root cap of new roots helps the root penetrate the soil. These root caps are sloughed off as the root goes deeper creating a slimy surface that provides lubrication. The apical meristem behind the root cap produces new root cells that elongate. Then, root hairs form that absorb water and mineral nutrients from the soil. The first root in seed producing plants is the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exocytosis
Exocytosis () is a form of active transport and bulk transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell ('' exo-'' + ''cytosis''). As an active transport mechanism, exocytosis requires the use of energy to transport material. Exocytosis and its counterpart, endocytosis, are used by all cells because most chemical substances important to them are large polar molecules that cannot pass through the hydrophobic portion of the cell membrane by passive means. Exocytosis is the process by which a large amount of molecules are released; thus it is a form of bulk transport. Exocytosis occurs via secretory portals at the cell plasma membrane called porosomes. Porosomes are permanent cup-shaped lipoprotein structure at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intra-vesicular contents from the cell. In exocytosis, membrane-bound secretory vesicles are carried to the cell membrane, where they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Bodies
The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus. It was identified in 1897 by the Italian scientist Camillo Golgi and was named after him in 1898. Discovery Owing to its large size and distinctive structure, the Golgi apparatus was one of the first organelles to be discovered and observed in detail. It was discovered in 1898 by Italian physician Camillo Golgi during an investigation of the nervous system. After first observing it under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
