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Cucumber Green Mottle Mosaic Virus
Cucumber green mottle mosaic virus (CGMMV) is a plant pathogenic virus. In Europe this virus disease is found since 1935. Watermelon and melon are also susceptible to this virus. Symptoms The virus affects the young leaves with green and light green spots, even yellow-green spots. These spots have a slower development rate than the rest of the leaf. Sometimes the veins remain green. In heavy infection young leaves are even deformed. The activity of the virus is reduced when the leaf ages. Fruit drop (abortion) is common. The rest of the fruits are small. Yield is reduced by 25% even more if no control action are taken into account. In the epidermis of the sick plants characteristic structures can be seen easily with a microscope. Virus ID: Tobamovirus group. Temperature inactivation in juice 90 °C Transition: seed 8–10% from the beginning which is enough to star the silent infection. Aphids and other sucking insects do not transmit the virus. In hydroponic the virus c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Microscope
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a sensor such as a scintillator attached to a charge-coupled device. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron microscopy is a major analytical method i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Review Of Phytopathology
The ''Annual Review of Phytopathology'' is a peer-reviewed academic journal that publishes review articles about phytopathology, the study of diseases that affect plants. It was first published in 1963 as the result of a collaboration between the American Phytopathological Society and the nonprofit publisher Annual Reviews. As of 2022, ''Journal Citation Reports'' lists the journal's 2021 impact factor as 10.850, ranking it seventh of 238 journal titles in the category "Plant Sciences". Its current editors are Jan E. Leach and Steven E. Lindow. History In the 1950s, the American Phytopathological Society had intended to publish its own journal to cover significant developments in the field of phytopathology, or plant diseases. However, the nonprofit publisher Annual Reviews offered to publish the journal for them, and they agreed due to their publishing experience. In 1961, the American Phytopathological Society compiled the editorial board of the journal at their annual m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen Sac (botany)
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent In Situ Hybridization
Fluorescence ''in situ'' hybridization (FISH) is a molecular cytogenetic technique that uses fluorescent probes that bind to only particular parts of a nucleic acid sequence with a high degree of sequence complementarity. It was developed by biomedical researchers in the early 1980s to detect and localize the presence or absence of specific DNA sequences on chromosomes. Fluorescence microscopy can be used to find out where the fluorescent probe is bound to the chromosomes. FISH is often used for finding specific features in DNA for use in genetic counseling, medicine, and species identification. FISH can also be used to detect and localize specific RNA targets ( mRNA, lncRNA and miRNA) in cells, circulating tumor cells, and tissue samples. In this context, it can help define the spatial-temporal patterns of gene expression within cells and tissues. Probes – RNA and DNA In biology, a probe is a single strand of DNA or RNA that is complementary to a nucleotide sequenc ... [...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 meaning t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Transmission
Vertical transmission of symbionts is the transfer of a microbial symbiont from the parent directly to the offspring. Many metazoan species carry symbiotic bacteria which play a mutualistic, commensal, or parasitic role. A symbiont is acquired by a host via horizontal, vertical, or mixed transmission. Implications Complex interdependence occurs between host and symbiont. The genetic pool of the symbiont is generally smaller and more subject to genetic drift. In true vertical transmission, the evolutionary outcomes of the host and symbiont are linked. If there is mixed transmission, new genetic material may be introduced. Generally, symbionts settle into specific niches and can even transfer part of their genome into the host nucleus. Evolutionary consequences Benefits The mechanism promotes tightly coupled evolutionary pressure, which causes the host and symbiont to function as a holobiont. Disadvantages Evolutionary bottlenecks lead to less symbiont diversity, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollination
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, and bats; water; wind; and even plants themselves, when self-pollination occurs within a closed flower. Pollination often occurs within a species. When pollination occurs between species, it can produce hybrid offspring in nature and in plant breeding work. In angiosperms, after the pollen grain (gametophyte) has landed on the stigma, it germinates and develops a pollen tube which grows down the style until it reaches an ovary. Its two gametes travel down the tube to where the gametophyte(s) containing the female gametes are held within the carpel. After entering an ovum cell through the micropyle, one male nucleus fuses with the polar bodies to produce the endosperm tissues, while the other fuses with the ovule to produce the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Reviews (publisher)
Annual Reviews is an independent, non-profit academic publishing company based in San Mateo, California. As of 2021, it publishes 51 journals of review articles and ''Knowable Magazine'', covering the fields of life, biomedical, physical, and social sciences. Review articles are usually “peer-invited” solicited submissions, often planned one to two years in advance, which go through a peer-review process. The organizational structure has three levels: a volunteer board of directors, editorial committees of experts for each journal, and paid employees. Annual Reviews' stated mission is to synthesize and integrate knowledge "for the progress of science and the benefit of society". The first Annual Reviews journal, the ''Annual Review of Biochemistry'', was published in 1932 under the editorship of Stanford University chemist J. Murray Luck, who wanted to create a resource that provided critical reviews on contemporary research. The second journal was added in 1939. By ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollinator
A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the major pollinators of most plants, and insect pollinators include all families of bees and most families of aculeate wasps; ants; many families of flies; many lepidopterans (both butterflies and moths); and many families of beetles. Vertebrates, mainly bats and birds, but also some non-bat mammals (monkeys, lemurs, possums, rodents) and some lizards pollinate certain plants. Among the pollinating birds are hummingbirds, honeyeaters and sunbirds with long beaks; they pollinate a number of deep-throated flowers. Humans may also carry out artificial pollination. A pollinator is different from a pollenizer, a plant that is a source of pollen for the pollination process. Background Plants fall into pollination syndromes that reflect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cucurbitaceae
The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family consisting of about 965 species in around 95 genera, of which the most important to humans are: *'' Cucurbita'' – squash, pumpkin, zucchini, some gourds *'' Lagenaria'' – calabash, and others that are inedible *'' Citrullus'' – watermelon (''C. lanatus'', ''C. colocynthis'') and others *'' Cucumis'' – cucumber (''C. sativus''), various melons and vines *'' Momordica'' – bitter melon *'' Luffa'' – the common name is also luffa, sometimes spelled loofah (when fully ripened, two species of this fibrous fruit are the source of the loofah scrubbing sponge) *'' Cyclanthera'' – Caigua The plants in this family are grown around the tropics and in temperate areas, where those with edible fruits were among the earliest cultivated plants in both the Old and New Worlds. The family Cucurbitaceae ranks among the highest of plant families for number and percentage of species used as human food ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphid
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescoping generations—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs. The life cycle of some species involves an alternation between two species of host plants, for example between an annual crop and a woody plant. Some species feed on only one type of plant, while others are generalists, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
