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Thigmotropism
In plant biology, thigmotropism is a directional growth movement which occurs as a mechanosensory response to a touch stimulus. Thigmotropism is typically found in twining plants and tendrils, however plant biologists have also found thigmotropic responses in flowering plants and fungi. This behavior occurs due to unilateral growth inhibition. That is, the growth rate on the side of the stem which is being touched is slower than on the side opposite the touch. The resultant growth pattern is to attach and sometimes curl around the object which is touching the plant. However, flowering plants have also been observed to move or grow their sex organs toward a pollinator that lands on the flower, as in '' Portulaca grandiflora''. Physiological factors Since growth is a complex developmental procedure, there are indeed many requirements (both biotic and abiotic) that are needed for both touch perception and a thigmotropic response to occur. One of these is calcium. In a series of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladonia Grayi
''Cladonia grayi'', commonly known as Gray's cup lichen or Gray's pixie cup, is a species of fruticose lichen in the family Cladoniaceae. It is characterised by small, leaf-like forming its and distinctive upright podetia (5–15 mm tall) that develop into goblet-shaped cups. The species contains several unique lichen substances, primarily grayanic acid, which causes it to glow light blue under ultraviolet light, and has also been found to produce protective pyrrolopyrazine compounds. Its is the green algal species ''Asterochloris glomerata''. The fungal component shows distinctive growth responses during development that occur only when encountering compatible algal cells, with the fungus growing extremely slowly at ≤1 cm per year in microbiological culture, culture. Though found worldwide, ''C. grayi'' is most abundant in Arctic and temperate regions of the Northern Hemisphere. It typically grows on acidic including rotting wood, organic soil layers, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunnichia Ovata
''Brunnichia ovata'' is a species of the buckwheat family that is found in North America. It was reassigned from the genus ''Rajania'' to ''Brunnichia'' by Lloyd Shinners in the publication ''Sida'' in 1967. Formerly it had been placed in ''Rajania'' by Thomas Walter in Flora Caroliniana in 1778. ''Brunnichia ovata'' plants grow near riverbanks, the perimeters of lakes, wet woods and thickets. This species is found in the buckwheat family, Polygonaceae. ''Brunnichia ovata'' is referred to by two other common names including American buckwheat vine and redvine. Description ''Brunnichia ovata'' is made up of an alternate leaf arrangement of its simple leaves. It is regarded as deciduous and the blades of its leaves are ovate or having an oval shape. Its leaves can range anywhere from 2 to 5 inches in length and its petioles are usually short. The flowering of the ''Brunnichia ovata'' species is typically seen from June to July and they are greenish in color. The fruit of the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lichen
A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), mutualistic relationship.Introduction to Lichens – An Alliance between Kingdoms . University of California Museum of Paleontology. . Lichens are the lifeform that first brought the term symbiosis (as ''Symbiotismus'') into biological context. Lichens have since been recognized as important actors in nutrient cycling and producers which many higher trophic feeders feed on, such as reindeer, gastropods, nematodes, mites, and springtails. Lichens have properties different from those of their component organisms. They come in man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nastic Movements
In biology, nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance) that occur more rapidly than tropisms and are usually associated with plants. The movement can be due to changes in turgor (internal pressure within plant cells). Decrease in turgor pressure causes shrinkage, while increase in turgor pressure brings about swelling. Nastic movements differ from tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements is independent of the stimulus's position. The tropic movement is growth movement but nastic movement may or may not be growth movement. The rate or frequency of these responses increases as intensity of the stimulus increases. An example of such a response is the opening and closing of flowers (photonastic response), movement of euglena, chlamydomonas towards the source of light . They are named with the suffix "-nasty" and have pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Rapid Plant Movement
Rapid plant movement encompasses movement in plant structures occurring over a very short period, usually under one second. For example, the Venus flytrap closes its trap in about 100 milliseconds. The traps of Utricularia are much faster, closing in about 0.5 milliseconds. The dogwood bunchberry's flower opens its petals and fires pollen in less than 0.5 milliseconds. The record is currently held by the white mulberry tree, with flower movement taking 25 microseconds, as pollen is catapulted from the stamens at velocities in excess of half the speed of sound—near the theoretical physical limits for movements in plants.Taylor, P.E., G. Card, J. House, M. H. Dickinson & R.C. Flagan 2006. High-speed pollen release in the white mulberry tree, ''Morus alba'' L.. ''Sexual Plant Reproduction'' 19(1): 19–24. These rapid plant movements differ from the more common, but much slower "growth-movements" of plants, called tropisms. Tropisms encompass movements that lead to physical, per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mimosa Pudica
''Mimosa pudica'' (also called sensitive plant, sleepy grass, sleepy plant, action plant, humble plant, touch-me-not, touch-and-die, or shameplant) is a creeping annual or perennial flowering plant of the pea/legume family Fabaceae. It is often grown for its curiosity value: the sensitive compound leaves quickly fold inward and droop when touched or shaken and re-open a few minutes later. For this reason, this species is commonly cited as an example of rapid plant movement. Like a number of other plant species, it undergoes changes in leaf orientation termed "sleep" or nyctinastic movement. The foliage closes during darkness and reopens in light. This was first studied by French scientist Jean-Jacques d'Ortous. In the UK it has gained the Royal Horticultural Society's Award of Garden Merit. The species is native to the Caribbean and South and Central America, but is now a pantropical weed, and can now be found in the Southern United States, South Asia, East Asia, Micronesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Gravitropic
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 bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root
In vascular plants, the roots are the plant organ, 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 root, 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. Types of Roots (major rooting system) Plants exhibit two main root system types: ''taproot'' and ''fibrous'', with variations like adventitious, aerial, and buttress roots, each serving specific functions. Taproot System Characterized by a single, main root growing vertically downward, with smaller lateral roots branching off. Examples. Dandelions, carrots, and many dicot plants. Fibrous RootSystem Consists of a network of thin, branching roots that spread out from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterochloris
''Asterochloris'' is a genus of green algae in the family Trebouxiophyceae. It is a common in lichen, occurring in the thalli of more than 20 lichen genera worldwide. ''Asterochloris'' is distinguishable from the morphologically similar genus ''Trebouxia'', primarily due to its deeply lobed chloroplast, the placement of the chloroplast along the cell's periphery before the initiation of zoospore or aplanospore formation, and its tendency to primarily reproduce asexually through the production of aplanospores. Taxonomy The genus was circumscribed in 1980 by Elisabeth Tschermak-Woess, with '' Asterochloris phycobiontica'' assigned as the type species. She differentiated it from the related genus ''Trebouxia'' by differences in chloroplast morphology. Later molecular research showed that ''Trebouxia'' was paraphyletic, and that some ''Trebouxia'' species were closely related to genus ''Asterochloris''. In 2010, Škaloud and Peksa proposed to split the genus ''Trebouxia'' and f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
