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Home >>Botany Dictionary>> Earth Stars - Endoplasmic Reticulum
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Earth Stars - Used for the fungal members of order Lycoperdales of Gasteromycetes (e.g., Geastrum triplex).
Ebracteolate - Lacking bracteoles.
Ecad - A plant form which is adapted to the habitat.
Eccentric, Excentric - (1) Situated to one side. (2) Having fatty droplets lying to one side of a globular
structure.
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Ecesis - The invasion of an area by a species which fails to establish itself there, and consequently dies out in a few generations.
Echard - The water present in the soil, which is not available to plants.
Ecocline - A cline that is due to a specific environmental factor e.g., gradual increase in heavy metal tolerance may be corre lated with increasing metal concentration in the soil.
Ecological Pyramids - Used for describing a graphic representation of some relationship which exists between trophic levels of an ecosystem. Magnitude of charactreristic for each level has been represented by the length of a horizontal bar and such bars have been drawn one above the other, starting from producers at the base to top carnivores at the top. Resulting pyramidical diagram is ecological pyramid which shows the relationship between trophic levels with respect to particular characteristic. Generally, pyramides of numbers, biomass and energy transfer have been drawn in the study of ecosystem as a rough representation of numerical, biomass or energy relationship among trophic levels of the ecosystem.
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Ecology - The branch of science dealing with the relationship between living organisms and their environment synecology.
Ecophene - Used for the range of phenotypes which are produced by one genotype within a particular habitat. One genotype may be considered to be taken as a mean of a class of closely related genotypes. Ecospecies - A category of variant individuals capable of genetic recombination with other similar groups, but liable to reduce fitness or fertility from it.
Ecosystem -.The complete ecological system of an area, that includes animals, and the environmental factors.
Ecotone - A boundary between two plant communities of major rank.
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Ecrustaceous - Describing a lichen with no well-defined thallus.
Ecotype - Describing a distinct population of organisms within a species that has adapted generally to its local habitat.
Ectogenesis - Variation occurring due to conditions outside the plant.
Ectogenic - (1) Of becteria, living on the outside of a body. (2) Describing the effect of pollen on the tissues of the female organs of a flowering plant.
Ectophlocodal - Living the outside of bark.
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Ectoparasite - When referring to a plant, a parasite which feeds from inside the host, but the bulk of the plant-body, and reproductive organs are outside the host.
Ectophloic Siphonostele - Used for siphonostele in which ring of phloem is present towards periphery and inner to it, towards centre, is ring of xylem and in the centre is pith.
Ectotrophic Mycorrhiza -(ectophytic mycorrhiza). Describing a form of mycorrhizal association having well developed mantle of fungal mycelium on the surface of the root. Fungal members generally belong to Agaricales and such association has been found to be common in trees and often necessary for proper growth of trees.
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Edaphic Factors (soil factors). Describing the various physical, chemical and biological properties of soil that influence the living organisms e.g., soil profile, soil texture, soil moisture, soil temperature etc.
Egg - A large, non-motile, uninucleate female gamete for sexual reproduction in organisms.
Egg Apparatus - The functional female nucleus, and the two synergidae in the embryo-sac of an angiosperm.
Ektexine: The outer layer of the exine of a pollen grain. It usually has projections on it.
Ektodynamorphous Soil - A soil whose characteristics are primarily affected by external. factors.
Elater - (1) In bryophytes, an elongated, spirally thickened cell which is derived from the sporogenous tissue, and sometime aiding in spore dispersal
.(2) One of the foul strips which is derived from the outer layer of the spore wall of Equisetum. It is hygroscopic, but its function is obscure.
Elaterophore - (1) A tissue bearing the elaters.
(2) A central column-like mass of sterile tissue present in the sporangium of the Jungermanniales.
Electron Transport Chain - Used for describing a series of mem brane bound oxidation reduction reactions in which elec trons being transferred from an initial electron doner through a series of intermediate substances to final electron acceptor. Such chains in respiration and photosynthesis form major sources of energy in aerobic living organisms.
Elfin Forest (Krummhol). Used for dwarfed and deformed trees found in the zone between timber line and tree line. These trees tend to grow along the ground that makes them better adapted to strong winds of these regions.
Emarginate - Used for describing a leaf, petal or a sepal having indentations at the tip e.g., notched petals of Geranium versicolor.
Emasculation - Describing the removal of anthers of a flower to prevent either selfpollination or pollination of surrounding plants.
Embden-Meyerhof-Parnass Sequence - The second phase in glycolysis,during aerobic respiration in which a molecule of hexose diphosphate is broken into two molecules of triose phosphate and two energy-rich phosphates are released. ADP is converted to A TP and NAD is reduced, with the formation of pyruvic acid:C6H12O6 - (2P) + 2NAD + 4ADP →2CH3 CO.COOH + 2NADH2 + 4ATP.
Embryo - A young plant which is developing from an egg-cell after fertilization, or without fertilization.
Embryo Sac - A large oval cell in the nucellus of the wall of flowering plants within which fertilisation occurs. A typical embryo sac is shown in Fig.
Embryo Culture - The growth of isolated plant embryos on suitable culture medium in vitro.
Embryogeny (embryogensis, embryony) - Describing the process of formation of embryo from a fertilized egg cell normally,
Embryoids - Used for non zygotic embryos which are formed in process of development of embryo from diploid somatic cells in suspension cultures as found in some angiosperms.
Embryo Sac - Used for the female gametophyte (megaspore) of angiosperms. It has several nuclei derived from the mega;spore nucleus, one of which is the egg-nucleus. Two other nuclei fuse to form the primary endosperm nucleus.
Emerson Effect (Emerson enhancement effect). This effect was observed by Robert Emerson in 1957 that photosynthesis proceeding slowly at illumination of wavelength 700 nm only become greatly increased when illumination of wavelength 700 nm and 650 nm are given together. This elucidates the energy trap in chloroplast absorbing light at 680 nm.
Enation - (1) An outgrowth, usually from a leaf.
(2) Outgrowth from the underside of the veins of a leaf,
Enchylema - The more fluid constituents of the cytoplasm.
Encystment - The formation of a walled, non-motile body from a swimming spore.
Endarch - Describing the direction of differentation of the xylem, when it is cut off from the cambium towards the centre of the axis.
Endemic - Used for a pest, or desease organism which occurs permanently in an area.
Endexine - Used for the inner one of the two layers of exine of pollen which has been recognized on the basis of chemical characteristics.
Endocarp - Used for the innermost layer of the pericarp of angiospermic fruit which is internal to mesocarp and external to seed(s). In some cases it may be stony e.g., in peach.
Endocytosis - Used for describing the entry of particles or fluid into a cell by any method other than diffusion or active uptake through the plasma membrane.
Endodermis - A layer of cells present at the boundary layer of cortex and stele. It is outer to pericycle, and regarded as the innermost layer of cortx. It is distinct in all roots, pterido phytes and incertain dicotyledonous stems. Cells generally have casparian strips. When endodermal cells are having numerous starch grains, it is terned as starch sheath.
Endogamy - (1) In-breeding.
(2) Pollination taking place between two flowers on the
same plant.
(3) The union of two sister gametes, both female.
Endogelatin - A gelationous layer present on the inner wall of the marcosporangia of the Fucales. When wet, It swells, forcing out the macrospores.
Endogenous Rhythms - Describing sequential physical or bio chemical processes occurring in a plant or its part in response to some stimuli from within e.g., continued periodicity of folding and unfolding of leaflets in certain plants even when kept in continuous darkness.
Endogenous Roots - Used for lateral branches in root system of plants that originate endogenously from the pericycle.
Endogenous Spore - A spore which is formed within a sporangium.
Endogenous Thallus - Used for a lichen thallus, in which the alga predominates:
Endomitosis - The doubling of the chromosomes without the division of the nucleus resulting in polyploidy.
Endoplasmic Reticulum - The submicroscopic, double layered membranes which are about l00 adm thick and consist of canaliculi and cisternae. They are much folded in the cytoplasm, and have microsomal particles usuall ribosomes at tached to them.
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