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Xenia (plants)
Xenia (also known as the Xenia effect) in plants is the effect of pollen on seeds and fruit of the fertilized plant. The effect is separate from the contribution of the pollen towards the next generation. The term was coined in 1881 by the botanist Wilhelm Olbers Focke to refer to effects on maternal tissues, including the seed coat and pericarp, but at that time endosperm was also thought to be a maternal tissue, and the term became closely associated with endosperm effects. The term metaxenia was later coined and is still sometimes used to describe the effects on purely maternal tissues. Endosperm effects in the seed One of the most familiar examples of xenia is the different colours that can be produced in maize (''Zea mays'') by assortment of alleles via individual pollen grains. Such maize cobs are cultivated for decorative purposes. The endosperm tissue, which makes up most of the bulk of a maize seed, is not produced by the mother plant, but is the product of fertilization, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corncobs Edit1
Corn on the cob is a culinary term for a cooked ear of sweet corn (maize) eaten directly off the cob. The ear is picked while the endosperm is in the "milk stage" so that the kernels are still tender. Ears of corn are steamed, boiled, or grilled usually without their green husks, or roasted with them. The husk leaves are removed before serving. Corn on the cob is normally eaten while still warm, and is often seasoned with salt and butter. Some diners use specialized skewers, thrust into the ends of the cob, to hold the ear while eating without touching the hot and sticky kernels. After being picked, the corn's sugar converts into starch: it takes only one day for it to lose up to 25% of its sweetness, so it is ideally cooked on the same day as it is harvested. Preparation The most common methods for cooking corn on the cob are frying, boiling, roasting, grilling, and baking. Corn on the cob can be grilled directly in its husk, or it can be shucked first and then wrapped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Olbers Focke
Wilhelm Olbers Focke (5 April 1834, Bremen – 29 September 1922, Bremen) was a medical doctor and botanist who in 1881 published a significant work on plant breeding entitled ''Die Pflanzen-Mischlinge, Ein Beitrag zur Biologie der Gewächse'' (The plant hybrids, a contribution to the biology of plants) which briefly mentioned Gregor Mendel's discoveries on hybridization. Although Charles Darwin had a copy of Focke's book he passed it along to a colleague apparently without reading this particular section. The rediscovery of Mendel's work is generally considered to have taken place in the first years of the 20th century, however in ''Die Pflanzen-Mischlinge'', Mendel is mentioned about 18 times - although Focke did not apparently take Mendel's work all that seriously. Along with hybridization, Focke analyzed the non-Mendelian phenomena of graft hybrids, pseudogamy, and xenia. In 1889 Focke conducted an inquiry into the former occurrence of malaria in Northern Germany. He also did ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in animal diet. For example, wheat endosperm is ground into flour for bread (the rest of the grain is included as well in whole wheat flour), while barley endosperm is the main source of sugars for beer production. Other examples of endosperm that forms the bulk of the edible portion are coconut "meat" and coconut "water", and corn. Some plants, such as orchids, lack endosperm in their seeds. Origin of endosperm Ancestral flowering plants have seeds with small embryos and abundant endosperm. The evolutionary development of flowering plants trends towards plants with mature seeds with little or no endosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences (or "tassels") and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are fruits. The term ''maize'' is preferred in formal, scientific, and international usage as a common name because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominance (genetics)
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomplete d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorghum
''Sorghum'' () is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species is grown for grain, while many others are used as fodder plants, either cultivated in warm climates worldwide or naturalized in pasture lands. Taxonomy ''Sorghum'' is in the Poaceae (grass) subfamily Panicoideae and the tribe Andropogoneae (the same as maize, big bluestem and sugarcane). Species Accepted species recorded include: Distribution and habitat Seventeen of the 25 species are native to Australia, with the range of some extending to Africa, Asia, Mesoamerica, and certain islands in the Indian and Pacific Oceans. Toxicity In the early stages of the plants' growth, some species of sorghum can contain levels of hydrogen cyanide, hordenine, and nitrates, which are lethal to grazing animals. Plants stressed by drought or heat can also contain toxic lev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccinium Corymbosum A2
''Vaccinium'' is a common and widespread genus of shrubs or dwarf shrubs in the heath family (Ericaceae). The fruits of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry (whortleberry), lingonberry (cowberry), and huckleberry. Like many other ericaceous plants, they are generally restricted to acidic soils. Description The plant structure varies between species: some trail along the ground, some are dwarf shrubs, and some are larger shrubs perhaps tall. Some tropical species are epiphytic. Stems are usually woody. Flowers are epigynous with fused petals, and have long styles that protrude from their bell-shaped corollas. Stamens have anthers with extended tube-like structures called "awns" through which pollen falls when mature. Inflorescences can be axillary or terminal. The fruit develops from an inferior ovary, and is a four- or five-parted berry; it is usually brightly coloured, often being red or blui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccinium Corymbosum
''Vaccinium corymbosum'', the northern highbush blueberry, is a North American species of blueberry which has become a food crop of significant economic importance. It is native to eastern Canada and the eastern and southern United States, from Ontario east to Nova Scotia and south as far as Florida and eastern Texas. It is also naturalized in other places: Europe, Japan, New Zealand, the Pacific Northwest of North America, etc.''Vaccinium corymbosum''. accessed 3.23.2013 Other common names include blue huckleberry, tall huckleberry, swamp huckleberry, high blueberry, and swamp blueberry. Description ''Vaccinium corymbosum'' is a deciduous shrub growing to tall and wide. It is often found in dense thickets. The dark glossy green leaves are elliptical and up to long. In autumn, the leaves turn to a brilliant red, orange, yellow, and/or purple. The flowers are long bell- or urn-shaped white to very light pink, long. The fruit is a diameter blue-black berry. This plant is fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amelanchier Arborea
''Amelanchier arborea'' (downy serviceberry or common serviceberry), is native to eastern North America from the Gulf Coast north to Thunder Bay in Ontario and Lake St. John in Quebec, and west to Texas and Minnesota. Other common names are "shadberries" (as their blossoming coincides with the shad runs in New England), "Juneberries" (because the berries usually set on in June), and "Service" or "Sarvice" berries because their blooms mean that the muddy back roads into the "coves and hollers" of Appalachia will soon be passable for circuit-riding preachers and the communities will be able to have Sunday services again. (Some say, more morbidly, that it means the ground is soft enough to dig, which means that those who died over winter can be buried and have services said over them.) ''Amelanchier arborea'' is generally tall. Occasionally, it can grow up to tall and reach into the overstory. The trunk can be up to in diameter (rarely to ). The bark is smooth and gray. The bud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetically Modified Crops
Genetically modified crops (GM crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering methods. Plant genomes can be engineered by physical methods or by use of ''Agrobacterium'' for the delivery of sequences hosted in T-DNA binary vectors. In most cases, the aim is to introduce a new trait to the plant which does not occur naturally in the species. Examples in food crops include resistance to certain pests, diseases, environmental conditions, reduction of spoilage, resistance to chemical treatments (e.g. resistance to a herbicide), or improving the nutrient profile of the crop. Examples in non-food crops include production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation. Farmers have widely adopted GM technology. Acreage increased from 1.7 million hectares in 1996 to 185.1 million hectares in 2016, some 12% of global cropland. As of 2016, major crop (soybean, maize, canola a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maternal Effect
A maternal effect is a situation where the phenotype of an organism is determined not only by the environment it experiences and its genotype, but also by the environment and genotype of its mother. In genetics, maternal effects occur when an organism shows the phenotype expected from the genotype of the mother, irrespective of its own genotype, often due to the mother supplying messenger RNA or proteins to the egg. Maternal effects can also be caused by the maternal environment independent of genotype, sometimes controlling the size, sex, or behaviour of the offspring. These adaptive maternal effects lead to phenotypes of offspring that increase their fitness. Further, it introduces the concept of phenotypic plasticity, an important evolutionary concept. It has been proposed that maternal effects are important for the evolution of adaptive responses to environmental heterogeneity. In genetics In genetics, a maternal effect occurs when the phenotype of an organism is determined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extranuclear Inheritance
Extranuclear inheritance or cytoplasmic inheritance is the transmission of genes that occur outside the nucleus. It is found in most eukaryotes and is commonly known to occur in cytoplasmic organelles such as mitochondria and chloroplasts or from cellular parasites like viruses or bacteria. Organelles Mitochondria are organelles which function to transform energy as a result of cellular respiration. Chloroplasts are organelles which function to produce sugars via photosynthesis in plants and algae. The genes located in mitochondria and chloroplasts are very important for proper cellular function. The mitochondrial DNA and other extranuclear types of DNA replicate independently of the DNA located in the nucleus, which is typically arranged in chromosomes that only replicate one time preceding cellular division. The extranuclear genomes of mitochondria and chloroplasts however replicate independently of cell division. They replicate in response to a cell's increasing energy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
