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Recalcitrant Palmoplantar Eruptions
Recalcitrant seeds are seeds that do not survive drying and freezing during ''ex situ'' conservation. By and large, these seeds cannot resist the effects of drying or temperatures less than 10 °C (50 °F); thus, they cannot be stored for long periods like orthodox seeds because they can lose their viability. Plants that produce recalcitrant seeds include avocado, mango, mangosteen, lychee, cocoa, rubber tree, some horticultural trees, aquatic plants such as ''Nymphaea caerulea'''','' and several plants used in traditional medicine, such as species of ''Virola'' and ''Pentaclethra''. Generally speaking, most tropical pioneer species have orthodox seeds but many climax species have recalcitrant or intermediate seeds. Mechanisms of damage The two main mechanisms causing damage to recalcitrant seeds are desiccation effects on the intracellular structures and metabolic damage from the formation of toxic chemicals such as free radicals. An example of the first type of damage woul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Mango And Cross Section Edit1
An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are cultivated worldwide. The tree originated in Central Asia, where its wild ancestor, ''Malus sieversii'', is still found. Apples have been grown for thousands of years in Eurasia before they were introduced to North America by European colonists. Apples have cultural significance in many mythologies (including Norse and Greek) and religions (such as Christianity in Europe). Apples grown from seeds tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. For commercial purposes, including botanical evaluation, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litchi Root
Lychee ( , ; ''Litchi chinensis''; ) is a monotypic taxon and the sole member in the genus ''Litchi'' in the soapberry family, Sapindaceae. There are three distinct subspecies of lychee. The most common is the Indochinese lychee found in South China, Malaysia, and northern Vietnam. The other two are the Philippine lychee (locally called ''alupag'' or ''matamata'') found only in the Philippines and the Javanese lychee cultivated in Indonesia and Malaysia. The tree has been introduced throughout Southeast Asia and South Asia. Cultivation in China is documented from the 11th century. China is the main producer of lychees, followed by India, Vietnam, other countries in Southeast Asia, other countries in South Asia, Madagascar, and South Africa. A tall evergreen tree, it bears small fleshy sweet fruits. The outside of the fruit is a pink-red, rough-textured soft shell. Lychee seeds contain methylene cyclopropyl glycine which has caused hypoglycemia associated with outbreaks of en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seedbank
A seed bank (also seed banks, seeds bank or seed vault) stores seeds to preserve genetic diversity; hence it is a type of gene bank. There are many reasons to store seeds. One is to preserve the genes that plant breeders need to increase yield, disease resistance, drought tolerance, nutritional quality, taste, etc. of crops. Another is to forestall loss of genetic diversity in rare or imperiled plant species in an effort to conserve biodiversity ''ex situ''. Many plants that were used centuries ago by humans are used less frequently now; seed banks offer a way to preserve that historical and cultural value. Collections of seeds stored at constant low temperature and low moisture are guarded against loss of genetic resources that are otherwise maintained in situ or in field collections. These alternative "living" collections can be damaged by natural disasters, outbreaks of disease, or war. Seed banks are considered seed libraries, containing valuable information about evolved st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Propagation
Plant propagation is the process by which new plants grow from various sources, including seeds, Cutting (plant), cuttings, and other plant parts. Plant propagation can refer to both man-made and natural processes. Propagation typically occurs as a step in the overall cycle of plant growth. For seeds, it happens after ripening and Seed dispersal, dispersal; for vegetative parts, it happens after detachment or pruning; for asexually-reproducing plants, such as strawberry, it happens as the new plant develops from existing parts. Countless plants are propagated each day in horticulture and agriculture. Plant propagation is vital to agriculture and horticulture, not just for human food production but also for forest and fibre crops, as well as traditional and herbal medicine. It is also important for plant breeding. Sexual propagation Seeds and spores can be used for reproduction (e.g. sowing). Seeds are typically produced from Plant sexuality, sexual reproduction within a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthodox Seed
Orthodox seeds are seeds which will survive drying and/or freezing during ''ex situ'' conservation, as opposed to recalcitrant seeds, which will not. According to information from the U.S. Department of Agriculture, there is variation in the ability of orthodox seeds to withstand drying and storage, with some seeds being more sensitive than others. Thus some seeds are considered intermediate in their storage capability while others are fully orthodox. One notable example of a long-lived orthodox seed which survived accidental storage followed by controlled germination is the case of the 2,000-year-old Judean date palm (cultivar of ''Phoenix dactylifera ''Phoenix dactylifera'', commonly known as the date palm, is a flowering-plant species in the palm family Arecaceae, cultivated for its edible sweet #Fruits, fruit called dates. The species is widely cultivated across North Africa, northern A ...'') seed which successfully sprouted in 2005. This particular seed is reputed t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropropagation
Micropropagation or tissue culture is the practice of rapidly multiplying plant stock material to produce many progeny plants, using modern plant tissue culture methods. Micropropagation is used to multiply a wide variety of plants, such as those that have been genetically modified or bred through conventional plant breeding methods. It is also used to provide a sufficient number of plantlets for planting from seedless plants, plants that do not respond well to vegetative reproduction or where micropropagation is the cheaper means of propagating (e.g. Orchids). Cornell University botanist Frederick Campion Steward discovered and pioneered micropropagation and plant tissue culture in the late 1950s and early 1960s. Steps In short, steps of micropropagation can be divided into four stages: # Selection of mother plant # Multiplication # Rooting and acclimatizing # Transfer new plant to soil Selection of mother plant Micropropagation begins with the selection of plant m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryopreservation
Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. At low temperatures (typically or using liquid nitrogen) any cell metabolism which might cause damage to the biological material in question is effectively stopped. Cryopreservation is an effective way to transport biological samples over long distances, store samples for prolonged periods of time, and create a bank of samples for users. Molecules, referred to as cryoprotective agents (CPAs), are added to reduce the osmotic shock and physical stresses cells undergo in the freezing process. Some cryoprotective agents used in research are inspired by plants and animals in nature that have unique cold tolerance to survive harsh winters, including: trees, wood frogs, and tardigrades. The first human corpse to be frozen with the hope of future resurrection was James Bedford's, a few hours after his c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Castanea Sativa
The sweet chestnut (''Castanea sativa''), also known as the Spanish chestnut or European chestnut, is a species of tree in the family Fagaceae, native to Southern Europe and Asia Minor, and widely cultivated throughout the Temperate climate, temperate world. A substantial, long-lived deciduous tree, it produces an edible seed, the chestnut, which has been used in cooking since ancient times. Description ''Castanea sativa'' attains a height of with a trunk often in diameter. Around 20 trees are recorded with diameters over including one in diameter at breast height. A famous ancient tree known as the Hundred Horse Chestnut in Sicily was historically recorded at in diameter (although it has split into multiple trunks above ground). The bark often has a net-shaped (retiform) pattern with deep furrows or fissures running spirally in both directions up the trunk. The trunk is mostly straight with branching starting at low heights. The Leaf shape, oblong-lanceolate, boldly toot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocky Mountain Research Station
The Rocky Mountain Research Station (RMRS) is one of five regional units that make up the United States Forest Service Research and Development organization — the most extensive natural resources research organization in the world. The station headquarters are located in Fort Collins, Colorado. Research is structured within eight science program areas. The Station employs over 400 permanent full-time employees, including roughly 100 research scientists. The station is dedicated to advancing the understanding and sustainable management of the nation's forests and grasslands through cutting-edge scientific research. With a focus on improving ecosystem health, resilience, and the utilization of natural resources, the RMRS plays a crucial role in addressing the challenges posed by climate change, natural disturbances, and human impact on the environment. One of the key areas of research at the RMRS is the study of wildfire and resilient landscapes. Through the development of new ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acorn
The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), enclosed in a tough Nutshell, shell known as the pericarp, and borne in a cup-shaped Calybium, cupule. Acorns are long and on the fat side. Acorns take between 5 and 24 months (depending on the species) to mature; see the List of Quercus species, list of ''Quercus'' species for details of oak classification, in which acorn morphology (biology), morphology and phenology are important factors. Etymology The word ''acorn'' (earlier ''akerne'', and ''acharn'') is related to the gothic language, Gothic name ''akran'', which had the sense of "fruit of the unenclosed land". The word was applied to the most important forest produce, that of the oak. Geoffrey Chaucer, Chaucer spoke of "achornes of okes" in the 14th century. By degrees, popular etym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardwood
Hardwood is wood from Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Characteristics Hardwoods are produced by Flowering plant, angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual dendrochronology, growth rings, but these may be absent in some tropical timber, tropical hardwoods. Hardwoods have a more complex structure than softwoods and are often much slower growing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Radical
A daughter category of ''Ageing'', this category deals only with the biological aspects of ageing. Ageing Biogerontology Biological processes Causes of death Cellular processes Gerontology Life extension Metabolic disorders Metabolism Old age Time in life {{CatAutoTOC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
