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Home >>Botany Dictionary >> Tachysoporous - Termonasty
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Teleutogonidium, Teleutospore - A thick-walled spore which consists of two or more cells. It is formed by a rust fungus towards the end of the growing season. They may remain dormant for sometime and then undergo germination giving one or more promycelia on which the basidiospores get formed.
Tangential Longitudial Section - Describing a section through a plant member parallel to a tangent to its surface.
Tannins - A group of complex compounds having phenols hydroxy-acids or glucosides.
Tannin Sac - A cell having much tannin.
Tapetal Plasmodium. A multinucleate mass which is formed by the breakdown of the cell walls present between the cells of the tapetum.
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Tapetum - A food rich layer of cells which is present around a group of spore-mother-cells in vascular plants. They get disintegrated to liberate the contents which get absorbed by the developing spores.
Tap Root - The robust primary root which is developed from radicle of embryo that persists. It is generally penetrating some depth below the ground level and sometimes modified as a storage organ. An example is Daucus carota (carrot).
Tachysoporous - Of a plant, treeing its seeds quickly.
Tachytelic - Term used in chronistics to describe that which from fossil evidence has evolved very rapidly.
Taiga - A wet wood land of siberia
Take-All - A disease of grasses and cereals which is caused by fungus gaeumannomyces (Ophiloholus) graminis. The pathogen survives in soil on crop debris and infect crops at any stage
Tautonym - A specific or intraspecific name that has exactly repeated the generic name e.g., Magnolia magnolia. Such names are not permitted in botanical nomenclatural code but are allowed in zoology.
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Taxis (tactic movement, pl taxes). Used for the free, directional, locomotor movement shown by whole organism that alters its physical position in response to external stimulus. In plants, such movements are exhibited by small unicellular organisms that are living in aquatic babital e.g., Euglena Moves by using flagellum and by certain reproductive cells and bacteria also..
Teleutosorus - Refers to a sorus in which teleutospores are formed.
Telemorphosis. The growing of a gametophyte into the clear area which is present between two strains of a heterothallic fungus grown in solid culture.
Teleutosorus - A group of teleutospores whose supporting hyphae, are forming a pustule on the surface of the host.
Taxon (pl. taxa). Used for the named taxonomic unit of any rank. For instance, family level taxon is Rosaceae, generic level taxon is Rosa. The organism contained within the rank e.g., genus, order or species can also be formed as taxon.
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Taxonomy - Dealing with the study of the principles and practices of characterization and classification. This term is strictly applicable to study and description of variation in the natural world and subsequent compilation of classification. This term is loosely employed to include systematics
Teleutostage - The stage in the life-history of a rust fungus when teleutospores have been formed.
Telocentric. Said of a chromosome that is having its centromere at or very close to one end so that only one arm of chromosome becomes visible. Compare acrocentric, metacentric.
Telome Theory - According to this theory there are certain plant organs which are derived from modified and reduced branch system and e.g., megaphylls are considered to be derived by flattening of a branch subsequent developing of mesophyll tissue (webbing) between branches.
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Telomitic - Said of chromosomes which are attached to the fibres of the spindle by their ends.
Telophase - Used for the terminal stage of mitosis or meiosis during which nuclei get reverted to the resting stage.
Telosynapsis, Telosyndesis (Metasyndesis). Said of the end - to end association of chromosomes in zygotene and pachytene.
Temperate Phage - (See Lysogenic Phage). A bacteriophage not killing its host.
Temperate Phage - A DNA phage is not necessarily inducing lysogeny in an infected bacterial cell, instead, phage DNA is getting incorporated into the bacterial chromosome and replicating along with it. The bacterium thus infected is known as lysogenic.
Temporary Collenchyma - Said of collenchyma which is present in a young organ. It disappears as secondary thickening progresses.
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Tendril - A stem, leaf, or part of a leaf which gets modified as a branched or unbranched filamentous structure. It is used by many climbers for attaching to a support by twining, or by adhesive terminal disks.
Tentacle - One of the hairs on the leaf of an insectivorous plant, which is help full in capturing insects and is producing enzymes which digest the prey.
Tent Pole - In certain gymnosperms, there occurs an extension of female gametophyte towards the pollen chamber as observed in Ginkgo bilobaalso characteristic of many fossil genera.
Tepal - Individual into of indistinct perianth in flower in which calyx and corolla are not differentiated as in most monocotyledonous plants. These are brightly coloured as in tulip.
Teratology - The study of abnormal growth and malformations.
Terete. Used for the structure which is smooth, cylindrical and tapering e.g., a grass
Terminalization - Describing the expansion of the association of the two pairs of chromatids on one side of a chiasma at the expanse of that on the other side. It is so called since the resulting 'movement' of the chiasma takes place towards the ends of the chromosomes.
Terpenes - The usaturated hydrocarbons (C10H16) which are essential oils with straight-chain or ring structure derived from isoprene.
Terra Rosa - A red soil which is associated with limestone. It is occurring in. countries bordering the Mediterranean Sea.
Tertiary - A geological era about 70-1 million years ago.
Tertiary Wall, Tertiary Layer, Tertiary Thickening - Used for the depositing of wall thickening on the inner surface of a secondary cell-wall, tracheid, or vessel, generally in the form of rings or a loose spiral.
Tertiary Structure - Describing the structure of a protein where the polypeptide chain is bent sharply thereby forming a roughly spherical, three-dimensional mass.
Testa. The seed coal which is derived from the integuments. It is several layers thick and is protective in function.
TestCross. A cross which takes place between a double or multiple heterozygote and the corresponding double or multiple recessive. It finds use in the estimating linkage relationships to the behaviour.
Tetrad - (1) A group of 4 spores which are formed by meiosis within a spore mother cell. .
(2) The paired chromosomes of meiosis, after each chromosome has undergone duplication itself, and the pair is visibly four-stranded.
Tetrad Analysis - The genetic analysis of four cells obtained from a meiotic division so as to gain information on the nature and extent of recombination. Such analysis is possible only in tetrad in which four cells are joined together.
Tetrad Division - The nuclear and cell divisions taking place when a spore mother cell undergoes division to give a spores.
Tetradynamous - Used for describing condition of androecium in which four long and two short stamens are present as in Cruciferae.
Tetramerous. Describing flower in which units of different whorls are in fours or multiples of four e.g., in members of Cruciferae.
Tetraploid - An organism or cell which is having four times the haploid number of chromosomes i.e., four sets or genome. Such a condition is obtained by fusion of two diploid gametes. See also autopolyploidy, allopolyploidy.
Tetrasomics - The zygote obtained by fusion of two gametes which are having some additional chromosome present in their genome. See aneuploidy. .
Tetrasporangium - The sporangium of some red algae e.g., Polysiphonia which is initially unicellular but then dividing meiotically to give four spores (tetraspores).
Tetrasporangium - Said of the sporangium of the tetrasporophyte of the red algae. Initially it is unicellular but the nucleus undergoes division meiotically to give 4 tetraspores.
Tetraspore - The spore which is produced in tetra sporangium by meiosis in certain red algae (e.g., Polysiphonia) on terasporophytes. These spores have been arranged in tetrahedral manner in the tetrasporangium. They are boat-shaped having a trriradiatemark on the inner surface. They are haploid, uninucleate and non-flagellate.
Tetrasporophyte. Said of the diploid phase in the life - cycle of the red algae It produces tetraspores.
Tetraster. A complex mitotic figure which is formed in an ovum after polyspermy.
Thalamifloral. Used for a flower which is having all its members inserted separately on the receptacle, with the gynoecium superior.
Thalamium - Used for the hymenium of an apothecium.
Thalamus - The receptacle of flower.
Thallophyta - Used for the most primitive division of the plant kingdom. Examples are the algae, fungi lichens and possibly the bacteria and myxomycetes. The plant body (thallus) is simple, being unicellular, multicellular, and even large, but is never differentated into stem, leaf and root. Asexual reproduction takes place by spores, and sexual reproduction by the fusion of gametes formed in sex-organs which consist essentially of single cells.
Thallospore - An asexual spore of the fungi which is not having conidiophore, or one which does not get separated from the hypha or conidiophore producing it. .
Termonasty. The response to general non-directional temperature stimulus.
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