
[[image:misc_pollen.jpg|thumb|right|300px|SEM image of pollen grains from a variety of common plants: sunflower (''Helianthus annuus''), morning glory (''Ipomea purpurea''),hollyhock (''Sildalcea malviflora''), lily (''Lilium auratum''), primrose(''Oenothera fruticosa''), and castor bean (''Ricinus communis''). ]] Pollen is a fine to coarse powder consisting of ''gamete'' (pollen grains), which carry the male gametes of spermatophyta. Each pollen grain contains one or two generative cells (the male gametes) and a vegetative cell. The group of three cells is surrounded by a cellulose cell wall and a thick, tough outer wall made of sporopollenin. Pollen is produced in the microsporangium (Stamen of an Flowering plant flower or male conifer cones of a Pinophyta plant). Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see photomicrograph at right). Most, but certainly not all, are spherical. Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the Forget-me-not plant (''Myosotis'' sp.), is around 6 micrometre (0.006 mm) in diameter. The study of pollen is called Palynology and is highly useful in paleontology, archeology, and forensics. The mature pollen-grain is, like other spores, a single cell; except in the case of some submerged aquatic plants, it has a double wall, a thin delicate wall of unaltered cellulose, the endospore or intine, and a tough outer cuticularized exospore or extine. The exospore often bears spines or warts, or is variously sculptured, and the character of the markings is often of value for the distinction of genera or higher groups. Germination of the microspore begins before it leaves the pollen-sac. In very few cases has anything representing prothallial development been observed; generally a small cell (the antheridial or generative cell) is cut off, leaving a larger tube-cell. The transfer of pollen grains to the female reproductive structure (''pistil'' in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Anemophilous plants typically produce great quantities of very lightweight pollen grains, and generally have inconspicuous flowers. Entomophilous (literally insect-loving) plants produce pollen that is relatively heavy and sticky, for dispersal by insect pollinators attracted to their flowers. When placed on the stigma, under favourable circumstances, the pollen-grain puts forth a pollen-tube which grows down the tissue of the style to the ovary, and makes its way along the placenta, guided by projections or hairs, to the mouth of an ovule. The nucleus of the tube-cell has meanwhile passed into the tube, as does also the generative nucleus which divides to form two male- or sperm-cells. The male-cells are carried to their destination in the tip of the pollen-tube. ==Hay Fever== [[Image:Honeybee_pollen_basket_5233.jpg|thumb|left|200px|Honeybee with collected pollen|A honeybee carrying pellet of pollen in its corbicula.]] ''Main article: Hay fever'' Allergy to pollen is called hay fever. Generally pollens that cause allergies are those of anemophilous, because the lightweight pollen grains are produced in great quantities for wind dispersal. Breathing air containing these pollen grains brings them into contact with the nasal passages. In the US, people often falsely blame the conspicuous entomophilous goldenrod flower for allergies. Since this pollen does not become airborne, the only way to get goldenrod pollen on the nasal passages would be to stick the flower up one's nose. The late summer and fall pollen allergies are usually caused by ragweed, a widespread anemophilous plant. Arizona was once regarded as a haven for people with pollen allergies, since ragweed does not grow in the desert. However, as suburbs grew and people began establishing irrigated lawns and gardens, ragweed gained a foothold and Arizona lost its claim of freedom from hay fever. Anemophilous spring blooming plants such as oak, hickory, pecan, and early summer grasses may also induce pollen allergies. Cultivated flowers are most often entomophilous and do not cause allergies. ==Miscellaneous== The "tapping panel dryness disease" of the rubber plant is caused by a virus (biology) transmitted on pollen grains. Water_lily_flower">Image:Flower-04-KayEss-2.jpeg|200px|thumb|right|A bee pollinating a Water lily flower Pollen is sold as a nutritional supplement, marketed as "bee pollen" (even though it is of course from flowers). Many trees and flowering plants are good Pollen source for honeybees. Bees will collect pollen from some grasses and grains when they cannot find pollens with more nutritional value, however, anemophilous plants such as grasses generally have very low real value to bees. Some windblown pollen is likely to be inadvertantly collected by bees, since they bear a static charge. Ragweed and pine pollen can settle on leaves and other flowers, to add to the total quantity of pollens that are found upon analysis of gathered pollen. ==External links== * [http://www.geo.arizona.edu/palynology/polident.html Pollen and Spore Identification Literature] * [http://www.flmnh.ufl.edu/natsci/paleobotany/paleobotany.htm Paleobotany and Palynology at the Florida Museum of Natural History] * [http://www.geo.arizona.edu/palynology/ Palynology at the University of Arizona] * [http://www.shef.ac.uk/uni/academic/N-Q/palysc/palyshef.html Palynology at the University of Sheffield] * [http://www.bio.uu.nl/~palaeo/Engels/engels.html Palynology in Utrecht, the Netherlands] Botany Palynology la:Pollen
"see photomicrograph at right", yet the caption said the image was made by a SEM. Isn't the image, therefore, an electron micrograph? == Nutritional values == This statment, as written needs editing, but I am not yet ready to do this myself. "Pollen is sold as a nutritional supplement, marketed as "bee pollen" (even though it is of course from flowers). It has no biological effect at all," This last phrase is quite debatable, and certainly does not represent a neutral point of view. User:Pollinator 03:42, 19 Sep 2003 (UTC) ..."except in triggering allergic reactions." This depends on what pollens are present, and it is also debatable whether consuming the pollens orally would have the same effect on the body as breathing them. User:Pollinator 03:42, 19 Sep 2003 (UTC) There was no response to my previous comment, so I simply removed the misleading line.User:Pollinator 18:54, 21 Oct 2003 (UTC) :While it is debatable, here's a source (citing several studies) that backs the information up; I'm sure it can be reintegrated in a more NPOV-appropriate way. [http://www.quackwatch.org/01QuackeryRelatedTopics/DSH/bee.html] --User:LostLeviathan 01:14, 20 Dec 2004 (UTC) == Featured pictures == Note that this relatively short article includes TWO featured pictures. Apparently this topic is better explained with photons than words. -- User:Solitude\User_talk:Solitude ">User:Solitude|User:Solitude\User_talk:Solitude 15:50, Nov 2, 2004 (UTC)
:You could replace the bee in the hay-fever section with :Image:Bumblebee closeup.jpg and make it three for three ;-) -- User:Solipsist 19:25, 3 Nov 2004 (UTC)
Pollen-- Welcome to Wikipedia, and thanks for doing the Fox Squirrel page, a gap that has wanted filling for some time. You've made a very good job of it. I have been gradually trying to tidy up the sciurid pages, but there is a lot of work needed on them and if you have expertise I hope you'll pitch in. User:Seglea 17:43, 19 Dec 2003 (UTC)
I'm 20 and I live on Earth. My exact location thereon tends to vary a bit, so I'll just leave it at Earth. I am ostensibly double-majoring in literature and social science at Friends World Program, but I spend quite a bit of my free time on internet projects such as this and Distributed Proofreaders (anything that doesn't require actual programming abilities), in parts of the world where I have a decent net connection at least. Find me at http://www.eastasiacenter.net/paulcox/ .
See other meanings of words starting from letter:
Words begining with Pollen:
Pollen
Pollen
Pollen
Pollen
Pollença
Polleniser
Pollenizer
Pollenizer
Pollenizers
Pollens
Pollen_basket
Pollen_core
Pollen_count
Pollen_source
Pollen_source
Pollen_tube
Pollen_tube
Pollen_tubes
Pollen_zone
Pollen
[[image:misc_pollen.jpg|thumb|right|300px|SEM image of pollen grains from a variety of common plants: sunflower (''Helianthus annuus''), morning glory (''Ipomea purpurea''),hollyhock (''Sildalcea malviflora''), lily (''Lilium auratum''), primrose(''Oenothera fruticosa''), and castor bean (''Ricinus communis''). ]] Pollen is a fine to coarse powder consisting of ''gamete'' (pollen grains), which carry the male gametes of spermatophyta. Each pollen grain contains one or two generative cells (the male gametes) and a vegetative cell. The group of three cells is surrounded by a cellulose cell wall and a thick, tough outer wall made of sporopollenin. Pollen is produced in the microsporangium (Stamen of an Flowering plant flower or male conifer cones of a Pinophyta plant). Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see photomicrograph at right). Most, but certainly not all, are spherical. Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the Forget-me-not plant (''Myosotis'' sp.), is around 6 micrometre (0.006 mm) in diameter. The study of pollen is called Palynology and is highly useful in paleontology, archeology, and forensics. The mature pollen-grain is, like other spores, a single cell; except in the case of some submerged aquatic plants, it has a double wall, a thin delicate wall of unaltered cellulose, the endospore or intine, and a tough outer cuticularized exospore or extine. The exospore often bears spines or warts, or is variously sculptured, and the character of the markings is often of value for the distinction of genera or higher groups. Germination of the microspore begins before it leaves the pollen-sac. In very few cases has anything representing prothallial development been observed; generally a small cell (the antheridial or generative cell) is cut off, leaving a larger tube-cell. The transfer of pollen grains to the female reproductive structure (''pistil'' in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Anemophilous plants typically produce great quantities of very lightweight pollen grains, and generally have inconspicuous flowers. Entomophilous (literally insect-loving) plants produce pollen that is relatively heavy and sticky, for dispersal by insect pollinators attracted to their flowers. When placed on the stigma, under favourable circumstances, the pollen-grain puts forth a pollen-tube which grows down the tissue of the style to the ovary, and makes its way along the placenta, guided by projections or hairs, to the mouth of an ovule. The nucleus of the tube-cell has meanwhile passed into the tube, as does also the generative nucleus which divides to form two male- or sperm-cells. The male-cells are carried to their destination in the tip of the pollen-tube. ==Hay Fever== [[Image:Honeybee_pollen_basket_5233.jpg|thumb|left|200px|Honeybee with collected pollen|A honeybee carrying pellet of pollen in its corbicula.]] ''Main article: Hay fever'' Allergy to pollen is called hay fever. Generally pollens that cause allergies are those of anemophilous, because the lightweight pollen grains are produced in great quantities for wind dispersal. Breathing air containing these pollen grains brings them into contact with the nasal passages. In the US, people often falsely blame the conspicuous entomophilous goldenrod flower for allergies. Since this pollen does not become airborne, the only way to get goldenrod pollen on the nasal passages would be to stick the flower up one's nose. The late summer and fall pollen allergies are usually caused by ragweed, a widespread anemophilous plant. Arizona was once regarded as a haven for people with pollen allergies, since ragweed does not grow in the desert. However, as suburbs grew and people began establishing irrigated lawns and gardens, ragweed gained a foothold and Arizona lost its claim of freedom from hay fever. Anemophilous spring blooming plants such as oak, hickory, pecan, and early summer grasses may also induce pollen allergies. Cultivated flowers are most often entomophilous and do not cause allergies. ==Miscellaneous== The "tapping panel dryness disease" of the rubber plant is caused by a virus (biology) transmitted on pollen grains. Water_lily_flower">Image:Flower-04-KayEss-2.jpeg|200px|thumb|right|A bee pollinating a Water lily flower Pollen is sold as a nutritional supplement, marketed as "bee pollen" (even though it is of course from flowers). Many trees and flowering plants are good Pollen source for honeybees. Bees will collect pollen from some grasses and grains when they cannot find pollens with more nutritional value, however, anemophilous plants such as grasses generally have very low real value to bees. Some windblown pollen is likely to be inadvertantly collected by bees, since they bear a static charge. Ragweed and pine pollen can settle on leaves and other flowers, to add to the total quantity of pollens that are found upon analysis of gathered pollen. ==External links== * [http://www.geo.arizona.edu/palynology/polident.html Pollen and Spore Identification Literature] * [http://www.flmnh.ufl.edu/natsci/paleobotany/paleobotany.htm Paleobotany and Palynology at the Florida Museum of Natural History] * [http://www.geo.arizona.edu/palynology/ Palynology at the University of Arizona] * [http://www.shef.ac.uk/uni/academic/N-Q/palysc/palyshef.html Palynology at the University of Sheffield] * [http://www.bio.uu.nl/~palaeo/Engels/engels.html Palynology in Utrecht, the Netherlands] Botany Palynology la:Pollen
Pollen
"see photomicrograph at right", yet the caption said the image was made by a SEM. Isn't the image, therefore, an electron micrograph? == Nutritional values == This statment, as written needs editing, but I am not yet ready to do this myself. "Pollen is sold as a nutritional supplement, marketed as "bee pollen" (even though it is of course from flowers). It has no biological effect at all," This last phrase is quite debatable, and certainly does not represent a neutral point of view. User:Pollinator 03:42, 19 Sep 2003 (UTC) ..."except in triggering allergic reactions." This depends on what pollens are present, and it is also debatable whether consuming the pollens orally would have the same effect on the body as breathing them. User:Pollinator 03:42, 19 Sep 2003 (UTC) There was no response to my previous comment, so I simply removed the misleading line.User:Pollinator 18:54, 21 Oct 2003 (UTC) :While it is debatable, here's a source (citing several studies) that backs the information up; I'm sure it can be reintegrated in a more NPOV-appropriate way. [http://www.quackwatch.org/01QuackeryRelatedTopics/DSH/bee.html] --User:LostLeviathan 01:14, 20 Dec 2004 (UTC) == Featured pictures == Note that this relatively short article includes TWO featured pictures. Apparently this topic is better explained with photons than words. -- User:Solitude\
Pollen
Pollen-- Welcome to Wikipedia, and thanks for doing the Fox Squirrel page, a gap that has wanted filling for some time. You've made a very good job of it. I have been gradually trying to tidy up the sciurid pages, but there is a lot of work needed on them and if you have expertise I hope you'll pitch in. User:Seglea 17:43, 19 Dec 2003 (UTC)
Pollen
I'm 20 and I live on Earth. My exact location thereon tends to vary a bit, so I'll just leave it at Earth. I am ostensibly double-majoring in literature and social science at Friends World Program, but I spend quite a bit of my free time on internet projects such as this and Distributed Proofreaders (anything that doesn't require actual programming abilities), in parts of the world where I have a decent net connection at least. Find me at http://www.eastasiacenter.net/paulcox/ .
See other meanings of words starting from letter:
P
PA | PB | PC | PD | PE | PF | PG | PH | PI | PJ | PK | PL | PM | PN | PO | PR | PS | PT | PU | PW | PX | PY | PZ |Words begining with Pollen:
Pollen
Pollen
Pollen
Pollen
Pollença
Polleniser
Pollenizer
Pollenizer
Pollenizers
Pollens
Pollen_basket
Pollen_core
Pollen_count
Pollen_source
Pollen_source
Pollen_tube
Pollen_tube
Pollen_tubes
Pollen_zone
These materials are based on Wikipedia and licensed under the GNU FDL
YouTube.com videos better site than Turbo Tax 2007
