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Hydrotropism
Hydrotropism (hydro- "water"; tropism "involuntary orientation by an organism, that involves turning or curving as a positive or negative response to a stimulus") is a plant's growth response in which the direction of growth is determined by a stimulus or gradient in water concentration. A common example is a plant root growing in humid air bending toward a higher relative humidity level. This is of biological significance as it helps to increase efficiency of the plant in its ecosystem. The process of hydrotropism is started by the root cap sensing water and sending a signal to the elongating part of the root. Hydrotropism is difficult to observe in underground roots, since the roots are not readily observable, and root gravitropism is usually more influential than root hydrotropism. Water readily moves in soil and soil water content is constantly changing so any gradients in soil moisture are not stable. Root hydrotropism research has mainly been a laboratory phenomenon for ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Tropism
In biology, a tropism is a phenomenon indicating the growth or turning movement of an organism, usually a plant, in response to an environmental stimulus (physiology), stimulus. In tropisms, this response is dependent on the direction of the stimulus (as opposed to nastic movements, which are non-directional responses). Tropisms are usually named for the stimulus involved; for example, a phototropism is a movement to the light source, and an anemotropism is the response and adaptation of plants to the wind. Tropisms occur in three sequential steps. First, there is a sensation to a stimulus. Next, signal transduction occurs. And finally, the directional growth response occurs. Tropisms can be regarded by Ethology, ethologists as ''taxis'' (directional response) or ''kinesis (biology), kinesis'' (non-directional response). The Cholodny–Went model, proposed in 1927, is an early model describing tropism in emerging shoots of monocotyledons, including the tendencies for the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Brockhaus And Efron Encyclopedic Dictionary B16 657-0
Brockhaus may refer to: * Friedrich Arnold Brockhaus (1772–1823), German encyclopedia publisher and editor ** F.A. Brockhaus AG, his publishing firm ** ''Brockhaus Enzyklopädie'', an encyclopedia published by the firm ** 27765 Brockhaus, an asteroid named for him * Hermann Brockhaus (1806–1877), German orientalist See also *Brockhaus and Efron Encyclopedic Dictionary The ''Brockhaus and Efron Encyclopaedic Dictionary'' (35 volumes, small; 86 volumes, large) is a comprehensive multi-volume encyclopaedia in Russian. It contains 121,240 articles, 7,800 images, and 235 maps. It was published in the Russian Em ..., a Russian-language encyclopedia {{disambiguation, surname German-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Gravitropism
Gravitropism (also known as geotropism) is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi. Gravity can be either "artificial gravity" or natural gravity. It is a general feature of all higher and many lower plants as well as other organisms. Charles Darwin was one of the first to scientifically document that roots show ''positive gravitropism'' and stems show ''negative gravitropism''. That is, roots grow in the direction of gravitational pull (i.e., downward) and stems grow in the opposite direction (i.e., upwards). This behavior can be easily demonstrated with any potted plant. When laid onto its side, the growing parts of the stem begin to display negative gravitropism, growing (biologists say, turning; see tropism) upwards. Herbaceous (non-woody) stems are capable of a degree of actual bending, but most of the redirected movement occurs as a consequence of root or stem growth outside. The mechanism is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a Common descent, common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation with Alfred Russel Wallace, he introduced his scientific theory that this Phylogenetics, branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.. Darwin has been described as one of the most influential figures in human history and was honoured by Burials and memorials in Westminster Abbey, burial in Westminster Abbey. Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh Medical Schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Vicia Faba
''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Varieties with smaller, harder seeds that are fed to horses or other animals are called field bean, tic bean or tick bean. This legume is commonly consumed in many national and regional cuisines. Some people suffer from favism, a hemolytic response to the consumption of broad beans, a condition linked to a metabolic disorder known as G6PDD. Otherwise the beans, with the outer seed coat removed, can be eaten raw or cooked. With young seed pods, the outer seed coat can be eaten, and in very young pods, the entire seed pod can be eaten. Description ''Vicia faba'' is a stiffly erect, annual plant tall, with two to four stems that are square in cross-section. The leaves are long, pinnate with 2–7 leaflets, and glaucous (grey-green). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Aquaporin
Aquaporins, also called water channels, are channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells. The cell membranes of a variety of different bacteria, fungi, animal and plant cells contain aquaporins through which water can flow more rapidly into and out of the cell than by diffusing through the phospholipid bilayer. Aquaporins have six membrane-spanning alpha helical domains with both carboxylic and amino terminals on the cytoplasmic side. Two hydrophobic loops contain conserved asparagine– proline– alanine ("NPA motif") which form a barrel surrounding a central pore-like region that contains additional protein density. Because aquaporins are usually always open and are prevalent in just about every cell type, this leads to a misconception that water readily passes through the cell membrane down its concentration gradient. Water can pass through th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Abscisic Acid
Abscisic acid (ABA or abscisin II) is a plant hormone. ABA functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure. It is especially important for plants in the response to environmental stresses, including drought, soil salinity, cold tolerance, freezing tolerance, heat stress and heavy metal ion tolerance. Discovery In the 1940s, Torsten Hemberg, while working at the University of Stockholm, found evidence that a positive correlation exists between the rest period and the occurrence of an acidic ether soluble growth inhibitor in potato tubers. In 1963, abscisic acid was first identified and characterized as a plant hormone by Frederick T. Addicott and Larry A. Davis. They were studying compounds that cause abscission (shedding) of cotton fruits (bolls). Two compounds were isolated and called abscisin I and abscisin II. Abscisin II is presently called abscisic acid (ABA). In plants Function ABA was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Arabidopsis Thaliana
''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small plant from the mustard family (Brassicaceae), native to Eurasia and Africa. Commonly found along the shoulders of roads and in disturbed land, it is generally considered a weed. A winter annual with a relatively short lifecycle, ''A. thaliana'' is a popular model organism in plant biology and genetics. For a complex multicellular eukaryote, ''A. thaliana'' has a relatively small genome of around 135 Base pair#Length measurements, megabase pairs. It was the first plant to have its genome sequenced, and is an important tool for understanding the molecular biology of many plant traits, including flower development and phototropism, light sensing. Description ''Arabidopsis thaliana'' is an annual plant, annual (rarely biennial plant, biennial) plant, usually growing to 20–25 cm tall. The leaf, leaves form a rosette at the base of the plant, with a few leaves also on the flowering Plant ste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Gravitropism
Gravitropism (also known as geotropism) is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi. Gravity can be either "artificial gravity" or natural gravity. It is a general feature of all higher and many lower plants as well as other organisms. Charles Darwin was one of the first to scientifically document that roots show ''positive gravitropism'' and stems show ''negative gravitropism''. That is, roots grow in the direction of gravitational pull (i.e., downward) and stems grow in the opposite direction (i.e., upwards). This behavior can be easily demonstrated with any potted plant. When laid onto its side, the growing parts of the stem begin to display negative gravitropism, growing (biologists say, turning; see tropism) upwards. Herbaceous (non-woody) stems are capable of a degree of actual bending, but most of the redirected movement occurs as a consequence of root or stem growth outside. The mechanism is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
