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Home >>Botany Dictionary>> F - Fission Fungi
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F - A class of flowers which are pollinated by butterflies and moths.
F1 - The first generation of a cross taking place between two individuals.
F2 - The second filial generation, which is produced by crossing or selffertilizing individuals of the F1 generation.
Factor - The inherited factor which is responsible for the inde pendent inheritance of a Mendelian difference. See Gene.
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F1 Hybrid - The variety of a crop which is produced by crossing two selected pure parental lines. Fl hybrids can have the qualities of both parental lines and usually exhibits hybrid vigour but do not breed true.
Factorial Experiment - An experiment in which all the treatments or agents under investigation have been varied simulataneously, and combined in such a way that any derived effect of one or goup of them may be isolated, and evaluated separately.
Factorial Experiment - An experiment in which all the treatments or agents under investigation have been varied simulatane ously, and combined in such a way that any derived effect of one or goup of them may be isolated, and evaluated sepa rately.
Factor of the Habitat - Anything in the environment affecting directly or indirectly, the life of a plant.
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Facultative - Used for the ability to utilize certain circumstances or environmental conditions but not being dependent on them. For example, a faculotative parasite can grow either parasitically or as saprophyte depending on the conditions.
Facultative Anaerobe - A plant respiring both under aerobic and anaerobic conditions.
Facultative Gamete - A zoospore functioning as a gamete.
Facultative Parasite - A saprophyte becoming a parasite under special conditions.
Facultative Saprophyte - A parasite living as saprophyte under special conditions.
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FAD (flavin adenine dinucleotide). A riboflavin-derived conenxyme which is acting as a prothetic group to several dehydrogenase enzymes. It accepts electrons and gets reduced to FADH2. Example of FAD-linked enzyme is succinate dehydrogenase. See also flavoprotein.
Falcate - Used for describing a thing which is sickle shaped. This term is usually used for leaves.
Fall - Used for any of the three large, outer, drooping petals of an Iris flower. They are bearded in some species (e.g., I. germanica).
False Annual Ring - A second ring of xylem which is formed in one season following abnormal defoliation, especially by insects.
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False Berry - A fleshy fruit looking like a berry, but that is having some of the flesh derived from the receptacle.
False Dissepiment - A wall which divides the loculus of an ovary into two compartments, but is an ingrwoth of the carpel wall, and not a wall between one carpel and the next.
False Fruit - A fruit which is formed from other parts of the flower as well as the gynoecium.
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False Hybrid - A plant which is developing after cross-fertilization, but having the characteristic of only one parent.
False Septum - Used for describing the partition wall that develops later in the middle of an originally unilocular ovary making it bilocular as in family Cruciferae.
Family - Used for the taxonomic division between an order and a genus, but may be a subdivision of a sub order, or super family. It possesses similar genera. The names of botanical families usually end in aceae.
Fasciation - Coming together to form a bundle.
Fascicle - (1) A tuft of branches all arising from about the same place.
(2) A tuft of liaves crowded on a short stem.
Fascicular Cambium - A flat strand of cambium which is present between the xylem and phloem of a vascular bundle.
Fasciculate - In bundles consisting of members all of the same kind.
Fastigate, Fastigiate - Having many branches which are parallel to the amin stem, and usually upright.
Fastigiate Cortex - Of lichens made up of parallel hyphae, at rightangles to the axis of the thallus.
Fat - Anester which is formed by the reaction between a fatty acid and glycerol, e.g. CH2OH CHO(C H CO)
CHOH+3C H COOH = CHO(C1sH31CO)+3HP
CH OH CHO(C H CO)
Fatty Acid - An acid which forms a fat when it reacts with glycerol. A saturated fatty acids has the basic formula CnH2nO2, e.g. CH3COOH, while that of unsaturated fatty acid is CnH2n-aO2 (where x=2,4,6, or 8). Those of biological importance usually have an even number of carbon atoms, and are in straight chains.
Fatty Acid Metabolism - Used for describing the breakdown or biosynthesis of fatty acid in living organism. In plants, fatty acids are broken down to yield CO2, water and energy but in many lipid metabolising tissues, especially germinating oil rich seeds fatty acids get metabolized to sugars. Major path way for fatty acid breakdown involves β oxidation cycle which degrades them to acetyl CoA which in turn can either undergo further oxidation or can be converted to sugar via glyoxylate cycle.
Feedback Inhibition - Describing the type of inhibition of a path way in which end produt of the pathway inhibits the activity of pathway at the starting point. An example is the inhibition of biosynthesis of isoleucine from threonine which is inhibited by isoleucine due to inhibition of first enzyme threonine dehydrogenase in the pathway.
Feedforward Stimulation - A phenomenon in which first sub strate of a pathway stimulates the activity. of subsequent reactions in the sequence.
Female - Used for describing either the reproductive parts or a whole organism that is bearing the megaspore producing apparatus.
Fen - Used for describing a £lot region of land which has developed from open stretches of baserich water that has gradually silted up and region has passed through hydrosereor halosere stage. The area is having a subclimax ccommunity because trees cannot grow due to persistent wet marshy condition even though there is built up of basic peat. Drained fenlands have been found to be agriculturally very productive.
Fermentation - The enzymatic anaerobic breakdown of a sub strate by microorganisms. More specifically it refers to the production of ethamnol nby yeasts, from monosaccharide sugars.
Ferns - Used for describing members of the class Filicinae ofPteri dophyta having about 10,000 species of chiefly tropical herba ceous plants most of which could be distinguished by their characteristics of fronds. All ferns except heterosporous water ferns are homosporous which bear sporangia on the abax ial surface of the lamina in distinct sori.
Feredoxin - Used for describing non haem iron sulphur protein. It is an important component of electron transport chain in chloroplasts where it mediates transfer of electrons between photosystem I and the ultimate electron acceptor, NADP via a feredoxin reducing substance and transfers them to NADP through a reaction which is catalysed by feredoxin NADP , reductase.
Fertilization - The fusion of gametes, which results in the formation of a zygote. Strictly it is confined to the fusion of nuclei, but sometimes it refers to condition in which the cells fuse, but not their nuclei, e.g., pseudogamy.
Fertilizer - Used for describing any substance that is applied to.
increase soil fertility and consequent increase in plant growth. It may be organic or inorganic. Three main constituents of fertilizers are nitrate, potash and phosphates; relative amount of these are expressed in N:P:K ratios.
F-Factor - Used for describing episome in cetain bacterial cells which is involved in determining maleness (donor) or femaleness (recepient) nature of bacterial cell in a particular strain.
Fibre - A narrow, elongated, lignified cell which is tapering to a wedge shape at both ends.
Fibre Tracheid(e) - An elongated cell which is found in wood, and has thicker walls and fewer pits than a tacheid, but thinner walls and more pits than a fibre.
Fibrous Cortex - Of lichens, having a cortex which is made up of huypae lying parallel with the longitudinal axis of the thallus.
Fibrous Layer - A layer of cells which is found in the wall of an anther. The cellwalls get thickened irregularly by bands of material.
Fibrous Root System - Used for describing a mass of fine adventitious roots, of more or less equal thickness, and bearing finer lateral roots. They are borne on stems or the hypocotyl, e.g., grasses.
Fibro- Vascular Bundle - A vascular bundle of sclerenchyma which is usually present on its outer side.
Field Capacity - The amount of water which is held in the micro spaces of soil after excess gravitational water has run off due to percolation.
Filament - (1) A chain of cells, set end-to-end.
(2) The stalk of a stamen.
(3) In the Cyanophyta, a trichome(s) and its enclosing sheath.
Filamentous - Thread-like.
Filamentous Iron Bacteria - The colourless rod-shaped gram negative bacteria of order Chlamydobacteriales that aggregate into filaments which sometimes get branched.
Filamentous Sulphur Bacteria - The filamentous bacteria of order beggiatoales that move by gliding over the substratum. They grow by oxidizing sulphides.
Filiform - Used for a structure that has thread like form.
Fire Blight - Used for describing a seriously damaging disease of pears and other members of rosaceae caused by bacterium Erwinia amylovora. It attacks blossoms and leaves in spring and with advancement of disease, branches and whole tree appears as if they are scorched by fire.
Fission - Used for a method of asexual reproduction which in volves splitting of nucleus and cytoplasm usually into two equal parts thereby forming new individuals genetically identical to the parent.
Fission Fungi - Used for describing the members of class Schizomycetes of fungi in older classifications which included bacteria also. Now the name is not used because bacteria are distinctly different from fungi.
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