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Purple Club-headed Fungus
''Claviceps purpurea'' is an ergot fungus that grows on the ears of rye and related cereal and forage plants. Consumption of grains or seeds contaminated with the survival structure of this fungus, the ergot sclerotium, can cause ergotism in humans and other mammals. ''C. purpurea'' most commonly affects outcrossing species such as rye (its most common host), as well as triticale, wheat and barley. It affects oats only rarely. Life cycle An ''ergot kernel'' called ''Sclerotium clavus'' develops when a floret of flowering grass or cereal is infected by an ascospore of ''C. purpurea''. The infection process mimics a pollen grain growing into an ovary during fertilization. Because infection requires access of the fungal spore to the stigma, plants infected by ''C. purpurea'' are mainly outcrossing species with open flowers, such as rye ('' Secale cereale'') and Alopecurus. The proliferating fungal mycelium then destroys the plant ovary and connects with the vasc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elias Magnus Fries
Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. Career Fries was born at Femsjö (Hylte Municipality), Småland, the son of the pastor there. He attended school in Växjö. He acquired an extensive knowledge of flowering plants from his father. In 1811 Fries entered Lund University where he obtained a doctorate in 1814. In the same year he was appointed an associate professorship in botany. He was elected a member of the Royal Swedish Academy of Sciences, and in 1824, became a full professor. In 1834 he became Borgström professor (Swed. ''Borgströmianska professuren'', a chair endowed by Erik Eriksson Borgström, 1708–1770) in applied economics at Uppsala University. The position was changed to "professor of botany and applied economics" in 1851. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1849. That year he was also appointed director of the Uppsala University Botanica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen
Pollen is a powdery substance produced by seed plants. 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. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conidia
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the way they are generated through the cellular process of mitosis. The two new haploid cells are genetically identical to the haploid parent, and can develop into new organisms if conditions are favorable, and serve in biological dispersal. Asexual reproduction in ascomycetes (the phylum Ascomycota) is by the formation of conidia, which are borne on specialized stalks called conidiophores. The morphology of these specialized conidiophores is often distinctive between species and, before the development of molecular techniques at the end of the 20th century, was widely used for identification of (''e.g.'' ''Metarhizium'') species. The terms microconidia and macroconidia are sometimes used. Conidiogenesis There are two main types of conidium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asexual Reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and eubacteria, bacteria. Many Eukaryote, eukaryotic organisms including plants, animals, and Fungus, fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Komodo dragons and some monitor lizards can also reproduce asexually. While all prokaryotes reproduce without the formation and fusion of gametes, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honeydew (secretion)
Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the anus of the aphid. Honeydew is particularly common as a secretion in hemipteran insects and is often the basis for trophobiosis. Some caterpillars of Lycaenidae butterflies and some moths also produce honeydew. Honeydew producing insects, like cicadas, pierce phloem ducts to access the sugar rich sap. The sap continues to bleed after the insects have moved on, leaving a white sugar crust called manna. Ants may collect, or "milk", honeydew directly from aphids and other honeydew producers, which benefit from their presence due to their driving away predators such as lady beetles or parasitic wasps—see ''Crematogaster peringueyi''. Animals and plants in a mutually symbiotic arrangement with ants are called Myrmecophiles. In Madagascar, some gecko species in the genera ''Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. 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 seed coat arises from the integuments of the ovule. Seeds have been an important development in the reproduction and success of vegetable gymnosperm and angiosperm plants, relative to more primitive plants such as ferns, mosses and liverworts, which 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. The term "seed" also has a general me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Bundle
A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues. In addition, there is also a tissue between xylem and phloem which is the cambium. The xylem typically lies towards the axis (adaxial) with phloem positioned away from the axis (abaxial). In a stem or root this means that the xylem is closer to the centre of the stem or root while the phloem is closer to the exterior. In a leaf, the adaxial surface of the leaf will usually be the upper side, with the abaxial surface the lower side. The sugars synthesized by the plant with sun light are transported by the phloem, which is closer to the lower surface. Aphids and leaf hoppers feed off of these sugars by tapping into the phloem. This is why aphids and leaf hoppers are typically found on the underside ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycelium
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrate (biology), substrates. A typical single spore germinates into a Monokaryon, monokaryotic mycelium, which cannot reproduce sexually; when two compatible monokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form sporocarp (fungi), fruiting bodies such as mushrooms. A mycelium may be minute, forming a colony that is too small to see, or may grow to span thousands of acres as in ''Armillaria''. Through the mycelium, a fungus absorbs nutrients from its environment. It does this in a two-stage process. First, the hyphae secrete enzymes onto or into the food source, which break down biopolymers, biological polymers into smaller units such as monomers. These monomers are then absorbed into the mycelium by facilitated diffusion and active transport. Mycelia are v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alopecurus
''Alopecurus'', or foxtail grass, is a common and widespread genus of plants in the grass family. It is common across temperate and subtropical parts of Eurasia, northern Africa, and the Americas, as well as naturalized in Australia and on various islands. Foxtails can be annual or perennial. They grow in tufts. They have flat leaves and blunt ligules (a small flap at the junction of leaf and stem). Their inflorescence is a dense panicle (a branching head without terminal flower) with 1-flowered spikelets. A few, particularly ''A. myosuroides'', are considered weeds, others are very decorative and are used in bouquets of dried flowers. ; Species * ''Alopecurus aequalis'' – Orange foxtail, shortawn foxtail – Eurasia, Americas * ''Alopecurus albovii'' – Caucasus * ''Alopecurus anatolicus'' – eastern Turkey * ''Alopecurus apiatus'' – Kyrgyzstan, Tajikistan, Afghanistan, Iraq, Iran * '' Alopecurus arundinaceus'' – Reed foxtail, creeping foxtail, creeping meadow foxtail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secale
''Secale'' is a genus of the grass tribe Triticeae, which is related to barley (''Hordeum'') and wheat (''Triticum''). The genus includes cultivated species such as rye (''Secale cereale'') as well as weedy and wild rye species. The most well known species of the genus is the cultivated rye, ''S. cereale'', which is grown as a grain and forage crop. Wild and weedy rye species help provide a huge gene pool that can be used for improvement of the cultivated rye.Chikmawati, T., Miftahudin, & Gustafson, J. P. (2013). Rye (''Secale cereale'' L.) and wheat (''Triticum aestivum'' L.) simple sequence repeat variation within ''Secale'' spp. (''Poaceae''). ''HAYATI Journal of Biosciences'', ''20''(4), 163–170. doi:10.4308/hjb.20.4.163 The genus ''Secale'' includes the cultivated rye and four to eleven wild species depending on the species criteria used. Commonly recognized species of the genus are the annuals, ''S. cereale'', ''S. vavilovii'' Grouch, and ''S. sylvestre'' and perennial '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anemophily
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plants are oaks, pecans, pistachios, sweet chestnuts, alders and members of the family Juglandaceae (hickory or walnut family). Approximately 12% of plants across the globe are pollinated by anemophily, including cereal crops like rice and corn and other prominent crop plants like wheat, rye, barley, and oats. In addition, many pines, spruces, and firs are wind-pollinated, and. Syndrome Features of the wind-pollination syndrome include a lack of scent production, a lack of showy floral parts (resulting in small, inconspicuous flowers), reduced production of nectar, and the production of enormous numbers of pollen grains. This distinguishes them from entomophilous and zoophilous species (whose pollen is spread by insects and vertebrates re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful technique in Animal husbandry, animal breeding. The outcrossing breeder intends to remove the traits by using "new blood." With dominant traits, one can still see the expression of the traits and can remove those traits whether one outcrosses, line breeds or inbreeds. With recessive traits, outcrossing allows for the recessive traits to migrate across a population. Many traits are Mendelian and therefore exhibit a more complicated intermediate phenotype. The outcrossing breeder then may have individuals that have many deleterious genes that may be expressed by subsequent inbreeding. There is now a gamut of deleterious genes within each individual in many dog breeds. Increasing the variation of genes or alleles within the gene pool may pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
