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Home >> Botany Dictionary >> Fragmentation - Fusiform Initials
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Fragmentation - A type of asexual reproduction in which body of a parent plant breaks up into smaller pieces, each of which is developed into a new plant.
Free Central Placentation - A type of Placentation in angiosperms in which ovary is multicarpellary, syncarpous and unilocular and placentae develop on a centreal dome or column of tissue that arises from the base of the ovary. This form of Placentation is found in Primulaceae and Caryophyllaceae.
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Free Space - The part of protoplasm in a cell in which relatively free exchange of inorganic ions between protoplasm and extracellular fluid can take place. It consists of the region lying between outer membrane of protoplasm and tonoplast. Ions can enter cell vacuole by active absorption but due to relative impermeability of tonoplast membrane, cannot pass out again.
Frond - Used for describing a large leaf or leaf like structure. This term is most frequently used for the dissected leaves of ferns, cycads and palms.
Frost Resistance - Used for the ability of many arctic and termperate plants to withstand subzero temperatures.
Fructification - Any structure bearing seeds, spores especially one which is easily visible e.g., aelrial fruiting bodies of many higher fungi.
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Fructosans - Used for polymers of ketosugar fructose, most im portant of which is inulin.
Fructose (fruit sugar, laevulose). A ketohexose sugar. In solution, it forms a ring to give fructofuranose. It is commonest keto sugar and component of disaccharide sucrose and also occurs freely as monosaccharide in plant tissue e.g., fruit juices.
Fructose 1:6 Biphosphate - A biphosphate of fructofuranose which is ultimately changed to two molecules of pyruvic acid during respiration.
Fruit: (1) Any of the fleshy structures associated with a gymno sperous seed like succulent aril of Taxus baccata or fleshy ovuliferous scales of some members of Podocarpaceae as in Juniperus.
(2) The structure which is developing from ovary wall and enclosing the maturing seeds in angiosperms. A fruit has been classified as dry or succulent on the basis of , dry or fleshy mesocarp and as dehiscent or indehiscent on the basis of whether it splits or not to release the seed(s).
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Fruit developing from gynoecium of a single flower is termed as simple or true fruit but if it is developing from an inflorescence, it is termed as multiple fruit. Aggregate fruits are developed from apocar pous polycarpellary ovary. A fruit may have tissue other that of gynoecium i.e., the pseudocarpic fruit or sometimes may develop without fertilization and seed formation, i.e., parthenocarpic fruit.
Fruit-Body - A well defined group of fungal spores and the hy phae which bear, and surround them.
Fruit Drop - Used for premature abscission of a fruit even before it I
is complete ripened. It is a normal process and in many plants peak period of fruit drop can be identified e.g. drop of apple fruits just after pollination (post blossom drop), during rapid embryo development (June drop) or during ripening of fruit (preharvest drop).
Frustule - Used for the siliceous wall of a diatom having intricate sculputuring. It is made up of two halves, one of which fits within the edges of the other.
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Fruticose - Used for organisms that grow erect and have much branching. This term is used especially to describe plant body of erect or pendent branching lichens e.g., Usnea.
Fumigant. Describing a volatile chemical which is used to kill pathogens in the soil or in glassfouses e.g., methyl bromide, chloropicrin, formaldehyde, ethylene dibromide and carbon disulphide.
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Fungi - Group of eukaryotic organisms that are heterotrophic, mostly saprophytes, parasites or symbionts having no chloro phyll, have characteristically chitinized walls or walls of fungal cellulose. Group includes some 50,000 species divided among some 5,100 genera.
Fungicide - Used for a chemical that kills fungi. It is used to prevent or control pathogenic fungi by applying to seeds as dust or slurry and to standing crops as spray or also to soil.
Fungi Imperfecti - Another name for Deuteromycotina which is artificial subdivision of Eumycota having all the fungi in which sexual stage has either not been found or has been replaced by some other mechanism e.g., parasexual recombination. Over 15,000 species in some 1,825 general have been included in it. Most of these show affinities with Ascomycetes.
Funiculus - (funicle). Representing a stalk that attaches the ovule to the placenta of ovary wall in angiosperms. It later attaches seed to the placenta.
Furanose Ring - Used for a ring having four carbon and oxygen a toms. It is formed by ketose sugars with five or more carbon a toms. Such rings are also formed by aldose sugars.
Fusiform - Used for structure that has elongated shape that tapers at both ends.
Fusiform Initials - Used for more or less elongate initials in vascular cambium which give rise to components of axial (longitudinal) system of secondary xylem and secondary phloem e.g., vesselelements, tracheids, sieve tube elements. They also give rise to ray initials.
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