Pollen in the context of Trimorphic


Pollen in the context of Trimorphic

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⭐ Core Definition: Pollen

Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells).

Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics.

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Pollen in the context of Waggle dance

Waggle dance is a term used in beekeeping and ethology for a particular figure-eight dance of the honey bee. By performing this dance, successful foragers can share information about the direction and distance to patches of flowers yielding nectar and pollen, to water sources, or to new nest-site locations with other members of the colony.

The waggle dance and the round dance are two forms of dance behaviour that are part of a continuous transition. As the distance between the resource and the hive increases, the round dance transforms into variations of a transitional dance, which, when communicating resources at even greater distances, becomes the waggle dance. In the case of Apis mellifera ligustica, the round dance is performed until the resource is about ten metres (33 ft) away from the hive, transitional dances are performed when the resource is at a distance of twenty to thirty metres (66 to 98 ft) away from the hive, and finally, when it is located at distances greater than forty metres (130 ft) from the hive, the waggle dance is performed. However, even close to the nest, the round dance can contain elements of the waggle dance, such as a waggle portion. It has therefore been suggested that the term waggle dance is better for describing both the waggle dance and the round dance.

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Pollen in the context of Taxodium

Taxodium /tækˈsdiəm/ is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. The name is derived from the Latin word taxus, meaning "yew", and the Greek word εἶδος (eidos), meaning "similar to." Within the family, Taxodium is most closely related to Chinese swamp cypress (Glyptostrobus pensilis) and sugi (Cryptomeria japonica).

Species of Taxodium occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south. They are large trees, reaching 100–150 ft (30–46 m) tall and 6.5–10 ft (2–3 m) (exceptionally 36 ft or 11 m) trunk diameter. The needle-like leaves, 0.2–0.8 in (0.5–2 cm) long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, 0.8–1.4 in (2–3.5 cm) diameter, with 10–25 scales, each scale with one or two seeds; they are mature in 7–9 months after pollination, when they disintegrate to release the seeds. The male (pollen) cones are produced in pendulous racemes, and shed their pollen in early spring. Taxodium species grow cypress knees, when growing in or beside water. The function of these knees is currently a subject of ongoing research.

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Pollen in the context of Maize

Maize (/mz/; Zea mays), also known as corn in North American English, is a tall stout grass that produces cereal grain. The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen, and female inflorescences called ears. The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte. Native Americans planted it alongside beans and squashes in the Three Sisters polyculture.

Maize relies on humans for its propagation. Since the Columbian exchange, it has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat and rice. Much maize is used for animal feed, whether as grain or as the whole plant, which can either be baled or made into the more palatable silage. Sugar-rich varieties called sweet corn are grown for human consumption, while field corn varieties are used for animal feed, for uses such as cornmeal or masa, corn starch, corn syrup, pressing into corn oil, alcoholic beverages like bourbon whiskey, and as chemical feedstocks including ethanol and other biofuels.

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Pollen in the context of Biofact (archaeology)

In archaeology, a biofact (or ecofact) is any organic material including flora or fauna material found at an archaeological site that has not been technologically altered by humans yet still has cultural relevance. Biofacts can include but are not limited to plants, seeds, pollen, animal bones, insects, fish bones and mollusks. The study of biofacts, alongside other archaeological remains such as artifacts are a key element to understanding how past societies interacted with their surrounding environment and with each other. Biofacts also play a role in helping archaeologists understand questions of subsistence and reveals information about the domestication of certain plant species and animals which demonstrates, for example, the transition from a hunter-gatherer society to a farming society.

Biofacts are differentiated from artifacts in that artifacts are typically considered anything purposefully manipulated or made by human art and workmanship, whereas ecofacts represent matter that has not been made or deliberately influenced by humans yet still has cultural relevance. Biofacts reveal how people respond to their surroundings.

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Pollen in the context of Hybrid (biology)

In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.

Species are reproductively isolated by strong barriers to hybridization, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled.

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Pollen in the context of Seed

In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a testa. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.

The formation of the seed is the defining part of the process of reproduction in seed plants (spermatophytes). Other plants such as ferns, mosses and liverworts, do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates.

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Pollen in the context of Ovary (plants)

In flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the base of the petals and sepals. The pistil may be made up of one carpel or of several fused carpels (e.g. dicarpel or tricarpel), and therefore the ovary can contain part of one carpel or parts of several fused carpels. Above the ovary is the style and the stigma, which is where the pollen lands and germinates to grow down through the style to the ovary, and, for each individual pollen grain, to fertilize one individual ovule. Some wind-pollinated flowers have much reduced and modified ovaries.

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Pollen in the context of Flower

Flowers, also known as blossoms and blooms, are the reproductive structures of flowering plants. Typically, they are structured in four circular levels around the end of a stalk. These include: sepals, which are modified leaves that support the flower; petals, often designed to attract pollinators; male stamens, where pollen is presented; and female gynoecia, where pollen is received and its movement is facilitated to the egg. When flowers are arranged in a group, they are known collectively as an inflorescence.

The development of flowers is a complex and important part in the life cycles of flowering plants. In most plants, flowers are able to produce sex cells of both sexes. Pollen, which can produce the male sex cells, is transported between the male and female parts of flowers in pollination. Pollination can occur between different plants, as in cross-pollination, or between flowers on the same plant or even the same flower, as in self-pollination. Pollen movement may be caused by animals, such as birds and insects, or non-living things like wind and water. The colour and structure of flowers assist in the pollination process.

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Pollen in the context of Carpel

Gynoecium (/ɡˈnsi.əm, ɪˈnʃi.əm/; from Ancient Greek γυνή (gunḗ) 'woman, female' and οἶκος (oîkos) 'house', pl. gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) pistils and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells.

The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are called pistillate or carpellate. Flowers lacking a gynoecium are called staminate.

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Pollen in the context of Bee

Bees are winged insects that form a monophyletic clade Anthophila within the superfamily Apoidea of the order Hymenoptera, with over 20,000 known species in seven recognized families. Some species – including honey bees, bumblebees, and stingless bees – are social insects living in highly hierarchical colonies, while over 90% of bee species – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary. Members of the most well-known bee genus, Apis (i.e. honey bees), are known to construct hexagonally celled waxy nests called hives.

Unlike the closely related wasps and ants, who are carnivorous/omnivorous, bees are herbivores that specifically feed on nectar (nectarivory) and pollen (palynivory), the former primarily as a carbohydrate source for metabolic energy, and the latter primarily for protein and other nutrients for their larvae. They are found on every continent except Antarctica, and in every habitat on the planet that contains insect-pollinated flowering plants. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, but they are small and often mistaken for wasps or flies. Bees range in size from tiny stingless bee species, whose workers are less than 2 millimeters (0.08 in) long, to the leafcutter bee Megachile pluto, the largest species of bee, whose females can attain a length of 39 millimeters (1.54 in). Vertebrate predators of bees include primates and birds such as bee-eaters; insect predators include beewolves and dragonflies.

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Pollen in the context of Beehive

A beehive is an enclosed structure in which honey bees raise their young and produce honey as part of their seasonal cycle. Although the word beehive is used to describe the nest of any bee colony, scientific and professional literature distinguishes nest from hive. Nest is used to discuss colonies that house themselves in natural or artificial cavities or in structures that are hanging and exposed. The term hive is used to describe a man made structure created to house a honey bee colony. While species of Apis live in colonies, the western (Apis mellifera) and eastern honey bees (Apis cerana) are the main species kept in artificial beehives.

The hive's internal structure is a densely packed group of hexagonal prismatic cells made of beeswax, called a honeycomb. The bees use the cells to store food (honey and pollen) and to house the brood (eggs, larvae, and pupae).

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Pollen in the context of Honeycomb

A honeycomb is a mass of hexagonal prismatic cells built from beeswax by honey bees in their nests to contain their brood (eggs, larvae, and pupae) and stores of honey and pollen.

Beekeepers may remove the entire honeycomb to harvest honey. Honey bees consume about 8.4 lb (3.8 kg) of honey to secrete 1 lb (450 g) of wax, and so beekeepers may return the wax to the hive after harvesting the honey to improve honey outputs. The structure of the comb may be left basically intact when honey is extracted from it by uncapping and spinning in a centrifugal honey extractor. If the honeycomb is too worn out, the wax can be reused in a number of ways, including making sheets of comb foundation with a hexagonal pattern. Such foundation sheets allow the bees to build the comb with less effort, and the hexagonal pattern of worker-sized cell bases discourages the bees from building the larger drone cells. Fresh, new comb is sometimes sold and used intact as comb honey, especially if the honey is being spread on bread rather than used in cooking or as a sweetener.

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Pollen in the context of Pollination

Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or butterflies; birds, and bats; water; wind; and even plants themselves. Pollinating animals travel from plant to plant carrying pollen on their bodies in a vital interaction that allows the transfer of genetic material critical to the reproductive system of most flowering plants. Self-pollination occurs within a closed flower. Pollination often occurs within a species. When pollination occurs between species, it can produce hybrid offspring in nature and in plant breeding work.

In angiosperms, after the pollen grain (gametophyte) has landed on the stigma, it germinates and develops a pollen tube which grows down the style until it reaches an ovary. Its two gametes travel down the tube to where the gametophyte(s) containing the female gametes are held within the carpel. After entering an ovule through the micropyle, one male nucleus fuses with the polar bodies to produce the endosperm tissues, while the other fuses with the egg cell to produce the embryo. Hence the term: "double fertilisation". This process would result in the production of a seed, made of both nutritious tissues and embryo.

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Pollen in the context of Eastern honey bee

Apis cerana, the eastern honey bee, Asiatic honey bee or Asian honey bee, is a species of honey bee native to South, Southeast and East Asia. This species is the sister species of Apis koschevnikovi and both are in the same subgenus as the western (European) honey bee, Apis mellifera. A. cerana is known to live sympatrically along with Apis koschevnikovi within the same geographic location. Apis cerana colonies are known for building nests consisting of multiple combs in cavities containing a small entrance, presumably for defense against invasion by individuals of another nest. The diet of this honey bee species consists mostly of pollen and nectar, or honey. Moreover, Apis cerana is known for its highly social behavior, reflective of its classification as a type of honey bee.

The terms Apis cerana indica and Apis Indica or Indian honey bee, is an historic term, with all Asian hive bees now referred to as Apis cerana.

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Pollen in the context of Marine isotope stages

Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data derived from deep sea core samples. Working backwards from the present, which is MIS 1 in the scale, stages with even numbers have high levels of oxygen-18 and represent cold glacial periods, while the odd-numbered stages are lows in the oxygen-18 figures, representing warm interglacial intervals. The data are derived from pollen and foraminifera (plankton) remains in drilled marine sediment cores, sapropels, and other data that reflect historic climate; these are called proxies.

The MIS timescale was developed from the pioneering work of Cesare Emiliani in the 1950s, and is now widely used in archaeology and other fields to express dating in the Quaternary period (the last 2.6 million years), as well as providing the fullest and best data for that period for paleoclimatology or the study of the early climate of the Earth, representing "the standard to which we correlate other Quaternary climate records". Emiliani's work in turn depended on Harold Urey's prediction in a paper of 1947 that the ratio between oxygen-18 and oxygen-16 isotopes in calcite, the main chemical component of the shells and other hard parts of a wide range of marine organisms, should vary depending on the prevailing water temperature in which the calcite was formed.

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