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Striga Hermonthica
''Striga hermonthica'', commonly known as purple witchweed or giant witchweed, is a hemiparasitic plant that belongs to the family Orobanchaceae. It is devastating to major crops such as sorghum (''Sorghum bicolor'') and rice (''Oryza sativa''). In sub-Saharan Africa, apart from sorghum and rice, it also infests maize (''Zea mays''), pearl millet (''Pennisetum glaucum''), and sugar cane (''Saccharum officinarum''). ''Striga hermonthica'' has undergone horizontal gene transfer from ''Sorghum'' to its nuclear genome. The ''S. hermonthica'' gene, ''ShContig9483'', is most like a ''Sorghum bicolor'' gene, and additionally shows significant but lesser similarity to a gene from ''Oryza sativa''. It shows no similarity to any known eudicot gene. Host and symptoms Purple witchweed infects a variety of grasses, and legumes in sub-saharan Africa including rice, maize, millet, sugarcane, and cowpea. The symptoms mimic that of drought or nutrient-deficiency symptoms. Chlorosis, wilt, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic Plant
A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature – either the xylem, phloem, or both. For example, plants like ''Striga'' or ''Rhinanthus'' connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like ''Cuscuta'' and some members of ''Orobanche'' connect to both the xylem and phloem of the host. This provides them with the ability to extract water and nutrients from the host. Parasitic plants are classified depending on the location where the parasitic plant latches onto the host (root or stem), the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weed Science Society Of America
The Weed Science Society of America (WSSA) is a nonprofit, learned society focused on weed science. It was founded in 1956. The organization promotes research, education, and extension outreach, provides science-based information to the public and policy makers, and fosters awareness of weeds and their impact on both managed and natural ecosystems. President for 2018-19 is Scott Senseman from the University of Tennessee. WSSA has started the International Survey of Herbicide Resistant Weeds initiative to collect herbicide resistances. The WSSA classifies all herbicides by the mode of action. In 2017, WSSA began a partnership with Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing hou ... to continue publication of the three WSSA journals: ''Weed Science'' , ''Wee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmodium
''Desmodium'' is a genus of plants in the legume family Fabaceae, sometimes called tick-trefoil, tick clover, hitch hikers or beggar lice. There are dozens of species and the delimitation of the genus has shifted much over time. These are mostly inconspicuous plants; few have bright or large flowers. Though some can become sizeable plants, most are herbs or small shrubs. Their fruit are loments, meaning each seed is dispersed individually enclosed in its segment. This makes them tenacious plants and some species are considered weeds in places. They have a variety of uses. Uses Several ''Desmodium'' species contain potent secondary metabolites that are released into the soil and aerially. Allelopathic compounds are used in agriculture in push-pull technology: ''Desmodium heterocarpon'', ''Desmodium intortum'', and ''Desmodium uncinatum'' are inter-cropped in maize and sorghum fields to repel ''Chilo partellus'', a stem-boring grass moth, and suppress witchweeds, including As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triton X-100
Triton X-100 (''n'') is a nonionic surfactant that has a hydrophilic polyethylene oxide chain (on average it has 9.5 ethylene oxide units) and an aromatic hydrocarbon lipophilic or hydrophobic group. The hydrocarbon group is a 4-( 1,1,3,3-tetramethylbutyl)-phenyl group. Triton X-100 is closely related to IGEPAL CA-630, which might differ from it mainly in having slightly shorter ethylene oxide chains. As a result, Triton X-100 is slightly more hydrophilic than Igepal CA-630 thus these two detergents may not be considered to be functionally interchangeable for most applications. Triton X-100 was originally a registered trademark of Rohm & Haas Co. It was subsequently purchased by Union Carbide and then acquired by Dow Chemical Company upon the acquisition of Union Carbide. Soon afterward (in 2009), Dow also acquired Rohm & Haas Co. Physical properties Undiluted Triton X-100 is a clear viscous fluid (less viscous than undiluted glycerol). Undiluted Triton X-100 has a viscosity of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smallholding
A smallholding or smallholder is a small farm operating under a small-scale agriculture model. Definitions vary widely for what constitutes a smallholder or small-scale farm, including factors such as size, food production technique or technology, involvement of family in labor and economic impact. Smallholdings are usually farms supporting a single family with a mixture of cash crops and subsistence farming. As a country becomes more affluent, smallholdings may not be self-sufficient, but may be valued for the rural lifestyle. As the sustainable food and local food movements grow in affluent countries, some of these smallholdings are gaining increased economic viability. There are an estimated 500 million smallholder farms in developing countries of the world alone, supporting almost two billion people. Small-scale agriculture is often in tension with industrial agriculture, which finds efficiencies by increasing outputs, monoculture, consolidating land under big agricu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusarium Oxysporum
''Fusarium oxysporum'' (Schlecht as emended by Snyder and Hansen), an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. It is part of the family Nectriaceae. Although their predominant role in native soils may be as harmless or even beneficial plant endophytes or soil saprophytes, many strains within the ''F. oxysporum'' complex are soil borne pathogens of plants, especially in agricultural settings. Taxonomy While the species, as defined by Snyder and Hansen, has been widely accepted for more than 50 years, more recent work indicates this taxon is actually a genetically heterogeneous polytypic morphospecies, whose strains represent some of the most abundant and widespread microbes of the global soil microflora. Genome The ' family of transposable elements was first discovered by Daboussi ''et al.'', 1992 in several ''formae speciales'' and Davière ''et al.'', 2001 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striga Hermonthica On Maize
''Striga'', commonly known as witchweed, is a genus of parasitic plants that occur naturally in parts of Africa, Asia, and Australia. It is currently classified in the family Orobanchaceae, although older classifications place it in the Scrophulariaceae. Some species are serious pathogens of cereal crops, with the greatest effects being in savanna agriculture in Africa. It also causes considerable crop losses in other regions, including other tropical and subtropical crops in its native range and in the Americas. Witchweeds are characterized by bright-green stems and leaves and small, brightly colored and attractive flowers.Sand, Paul, Robert Eplee, and Randy Westbrooks. Witchweed Research and Control in the United States. Champaign, IL: Weed Science Society of America, 1990. They are obligate hemiparasites of roots and require a living host for germination and initial development, though they can then survive on their own. The number of species is uncertain, but may exceed 40 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haustorium
In botany and mycology, a haustorium (plural haustoria) is a rootlike structure that grows into or around another structure to absorb water or nutrients. For example, in mistletoe or members of the broomrape family, the structure penetrates the host's tissue and draws nutrients from it. In mycology, it refers to the appendage or portion of a parasitic fungus (the hyphal tip), which performs a similar function. Microscopic haustoria penetrate the host plant's cell wall and siphon nutrients from the space between the cell wall and plasma membrane but do not penetrate the membrane itself. Larger (usually botanical, not fungal) haustoria do this at the tissue level. The etymology of the name corresponds to the Latin word ''haustor'' meaning ''the one who draws, drains or drinks'', and refers to the action performed by the outgrowth. In fungi Fungi in all major divisions form haustoria. Haustoria take several forms. Generally, on penetration, the fungus increases the surface ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strigolactone
Strigolactones are a group of chemical compounds produced by a plant's roots. Due to their mechanism of action, these molecules have been classified as plant hormones or phytohormones. So far, strigolactones have been identified to be responsible for three different physiological processes: First, they promote the germination of parasitic organisms that grow in the host plant's roots, such as ''Striga'' ''lutea'' and other plants of the genus ''Striga''. Second, strigolactones are fundamental for the recognition of the plant by symbiotic fungi, especially arbuscular mycorrhizal fungi, because they establish a mutualistic association with these plants, and provide phosphate and other soil nutrients. Third, strigolactones have been identified as branching inhibition hormones in plants; when present, these compounds prevent excess bud growing in stem terminals, stopping the branching mechanism in plants. Strigolactones comprise a diverse group, but they all have core common chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorosis
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates through photosynthesis and may die unless the cause of its chlorophyll insufficiency is treated and this may lead to a plant diseases called rusts, although some chlorotic plants, such as the albino ''Arabidopsis thaliana'' mutant ''ppi2'', are viable if supplied with exogenous sucrose. The word ''chlorosis'' is derived from the Greek ''khloros'' meaning "greenish-yellow", "pale green", "pale", "pallid", or "fresh". In viticulture, the most common symptom of poor nutrition in grapevines is the yellowing of grape leaves caused by chlorosis and the subsequent loss of chlorophyll. This is often seen in vineyard soils that are high in limestone such as the Italian wine region of Barolo in the Piedmont, the Spanish wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orobanchaceae
Orobanchaceae, the broomrapes, is a family of mostly parasitic plants of the order Lamiales, with about 90 genera and more than 2000 species. Many of these genera (e.g., ''Pedicularis'', ''Rhinanthus'', ''Striga'') were formerly included in the family Scrophulariaceae ''sensu lato''. With its new circumscription, Orobanchaceae forms a distinct, monophyletic family. From a phylogenetic perspective, it is defined as the largest crown clade containing '' Orobanche major'' and relatives, but neither ''Paulownia tomentosa'' nor ''Phryma leptostachya'' nor '' Mazus japonicus''. The Orobanchaceae are annual herbs or perennial herbs or shrubs, and most (all except ''Lindenbergia'', ''Rehmannia'' and ''Triaenophora'') are parasitic on the roots of other plants—either holoparasitic or hemiparasitic (fully or partly parasitic). The holoparasitic species lack chlorophyll and therefore cannot perform photosynthesis. Description Orobanchaceae is the largest of the 20–28 dicot fami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eudicot
The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots by previous authors. The botanical terms were introduced in 1991 by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton to emphasize the later evolutionary divergence of tricolpate dicots from earlier, less specialized, dicots. Numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Some common and familiar eudicots include sunflower, dandelion, forget-me-not, cabbage, apple, buttercup, maple, and macadamia. Most leafy trees of midlatitudes also belong to eudicots, with notable exceptions being magnolias and tulip trees which belong to magnoliids, and ''Ginkgo biloba'', which is not an angiosperm. Description The close relationships among flowering plants with tricolpate po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
