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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 :wikt:ear#earofcorn, ear of sweet corn (maize) eaten directly off the corncob, cob. The ear is picked while the endosperm is in the "milk stage" so that the caryopsis, 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 ... [...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 d ... [...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#Plant embryos, embryo and provides nutrition in the form of starch, though it can also contain Vegetable oil, 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 Maize, corn. Some plants, such as certain orchids, lack endosperm in their seeds. Ancestral flowering plants have seeds with small embryos and abundant endosperm. In some modern flowering plants the embryo occupies most of the seed and the endosperm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout grass that produces cereal grain. It 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. 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 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 sw ... [...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 is called 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 Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance, such as incomp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorghum
''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain is used as food by humans, while the plant is used for animal feed and ethanol production. Sorghum originated in Africa, and is widely cultivated in tropical and subtropical regions. Sorghum is the world's fifth-most important cereal crop after rice, wheat, maize, and barley. Sorghum is typically an annual, but some cultivars are perennial. It grows in clumps that may reach over high. The grain is small, in diameter. Sweet sorghums are cultivars grown for forage, syrup production, and ethanol. They are taller than those grown for grain. Description Sorghum is a large stout grass that grows up to tall. It has large bushy flowerheads or panicles that provide an edible starchy grain with up to 3,000 seeds in each flowerhead. It grows ... [...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 heath plants, they are 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 red or bluish with purple juice. Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccinium Corymbosum
''Vaccinium corymbosum'', the northern highbush blueberry, is a North American species of blueberry. 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.''Vaccinium corymbosum''. accessed 3.23.2013 The flowers are long bell- or urn-shaped white to very light pink, long. The fruit is a blue-black berry with a diameter. The species is tetraploid and does not self-pollinate. Most cultivars have a chilling requirement greater than 800 hours. Cytology is 2n = 48. Distribution and habitat 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 n ... [...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 b ... [...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 and ... [...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 need ... [...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 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
