Autogamy 1. Self-fertilization, the fertilization of a flower by its own pollen. 2. The fusion of nuclei in paris within a single cell of the female organ but not accompanied by cell fusion.

Auxin An accessory growth-promoting substance in the food of plants, a hormone produced in the tips of plants which travels through the plant from cell to cell. Auxin veers away from light and causes the plant to grow faster on one side and curve toward light.

Autogamous Requiring only one individual to accomplish self-fertilization.

Autogamy 1. Self-fertilization, the fertilization of a flower by its own pollen. 2. The fusion of nuclei in paris within a single cell of the female organ but not accompanied by cell fusion.

Actinomycete Gk. aktis - ray, mukes - fungus.

Group of heterotropic filamentous eubacteria tending to form extremely fine ramified mycelia. They multiply by mere breaking of the mycelium or by hyphae. The most common genera in soil (Streptomyces and Nocardia) are particularly able to degrade organic substances which cannot easily by decomposed, thereby producing vitamins and antibiotics. Being aerobic, their presence in a soil signifies good structure and good aeration. They can be symbiotic with some higher plants such as Alnus and Myrica

Albumen Nutritive material stored within the seed usually surrounding the embryo but not within the embryo, the nutritive matter in the seed used by the young plant until it develops roots and leaves; see ENDOSPERM.

Allele One of the forms of a gene.

Allogamous Requiring two individuals to accomplish sexual reproduction; habitually cross-fertilized although capable of self-fertilization

Allogamy Cross-fertilization; see geitonogamy; the opposite of autogamy.

Anthesis The period of flowering, the time of the expansion of a flower, the period of pollination.

Biotope The life area of the smallest space, a microhabitat within the phytocoenosis.

Bract 1. A relatively small leaf just below an inflorescence, flower, or flower part (see illustration morphology of flower heads). 2. A leaf or scale in whose axis an inflorescence, flower, or floral organ is produced. 3. A small rudimentary or imperfectly developed leaf. 4. A leaf subtending a flower.

Brix The Brix scale is a measure of the percent of sugar in the solution or of the number of grams of sucrose present per 100 grams of aqueous sugar solution. (50 Brix means 50 grams of solid per 100 gms of solution)

Bud The undeveloped state of a branch or flower cluster with or without scales, an undeveloped shoot or stem, the rudimentary or resting end or branch of a stem, an embryonic shoot, a growing point or undeveloped axis covered with the rudiments of leaves.

C3 Photosynthesis pathway Calvin cycle (aka Calvin-Benson Cycle or Carbon Fixation) (also referred to as a C-3 pathway) is a series of biochemical, enzyme-mediated reactions during which atmospheric CO2 is reduced and incorporated into organic molecules, eventually some of this forms sugars. The Calvin Cycle occurs in the stroma of chloroplasts. CO2 is captured by the chemical ribulose biphosphate (RuBP). Six molecules of CO2 enter the Calvin Cycle, eventually producing one molecule of glucose.
The first stable product of the Calvin Cycle is phosphoglycerate (PGA). The energy from ATP and NADPH energy carriers generated by the photosystems is used to attach phosphates to (phosphorylate) the PGA. Eventually there are 12 molecules of glyceraldehyde phosphate (also known as phosphoglyceraldehyde or PGAL), two of which are removed from the cycle to make a glucose. The remaining PGAL molecules are converted by ATP energy to reform 6 RuBP molecules, and thus start the cycle again.

Calyx The outer floral envelope of the flowering plants usually green in color and composed of sepals, the sepals considered collectively, the outer set of the floral envelope. When there is but one set, it is considered the calyx. See illustration morphology of flowers or morphology of apple flower and fruit.

Cambium The thin layer of formative tissue beneath the bark of dicotyledons and gymnosperms from which new wood and bark originate, a sheath of generative tissue ordinarily between the xylem and phloem, the meristematic zone from which new growth develops, the secondary tissue from which secondary growth arises in stems and roots. See illustration changes in a stem as it increases in age or details of stem structure.

Canopy 1. The layer of branches, twigs, and leaves formed by woody plants at some distances above ground level. 2. A characteristic membrane within the testa surrounding the free part of the nucleus.

Carbohydrate Any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds. Carbohydrates are produced naturally by green plants from carbon dioxide and water (see photosynthesis). Essential nutrients, they are the human body's main source of both quick and sustained energy. The three main classes of carbohydrates are monosaccharides, which are the simple sugars, e.g., fructose and glucose; disaccharides, which are made up of two monosaccharide units and include lactose, maltose, and sucrose; and polysaccharides, which are polymers with many monosaccharide units and include cellulose, glycogen, and starch.

Carpel One of the female reproductive organs of the flower, i.e. a unit of the gynoecium. See illustration main types of gynoecium, morphology of apple flower and fruit or morphology of citrus flower and fruit.

Cation exchange capacity The total number of negatively charged ion sites in a given volume of soil. These may be linked either to basic ions (e.g. potassium) or hydrogen ions. As the proportion of hydrogen ions increase so the acidity increases and the pH falls.

Cation exchange capacity The cation exchange capacity (CEC) is a measure of the soil's ability to retain cationic nutrients. It is also an index of the clay activity and mineralogy, which is important for calculating mineralisation rates, leaching rates and interaction with pollutants. It changes relatively slowly, and largely due to changes in the soil organic carbon and pH.
When dissolved in water, the nutrients are either positively charged or negatively charged. Examples of positively charged ions (cations) include: calcium (Ca++), magnesium (Mg++), potassium (K+), sodium (Na+), hydrogen (H+) and ammonium (NH4+). Soils have a slight excess of negative charge sites due to the presence of clay particles and organic matter. Thus the higher the clay content and organic matter content, the higher the CEC of the soil. Soils with a high CEC will tend to hold onto the positively charged nutrients better than soils with a low CEC.

Cellulose The carbohydrate which composes the cell walls; the primary cell-wall substance; an amorphous white compound which is isomeric with starch and insoluble in ordinary solvents; the raw material for the manufacture of paper, artificial silk, laquers, films, etc.

Chiasma The exchange of material between chromosomes during nuclear division, a crosswise fusion at one or more points of paired chromosomes or chromatids which are twisted about each other in meiosis; an exchange of partners in a system of paired chromatids, a visible genetic cross-over between chromosomes and chromatids; pl. chiasmata.

Chromosome A single DNA molecule, a tightly coiled strand of DNA, condensed into a compact structure in vivo by complexing with accessory histones or histone-like proteins. Chromosomes exist in pairs in higher eukaryotes. See chromosome walking.
Derives from: chroma + soma.

Coir Fibrous material derived from the outer husk of Cocos nucifera, the coconut palm; used as an environmentally friendly fibre.

Cortex 1. A cylinder of parenchymatous cells between the epidermis and the starch sheath (the endodermis) in a young stem and between the piliferous layer and the endodermis in a young root (see illustration primary plant body of a root or details of stem structure).
2. A similar cylinder in the older stems and roots, but less conspicuous.
3. A cellurar coating on the outide of the thalli of some algae.
4. The outer layers of the thallus in lichens and some fungi.

Cotyledon The seedleaf, a leaf-like organ within the seed, a leaf-like structure folded within a seed in which food for the new plant is usually stored. The number of cotyledons in a seed is the basis for the primary divisions of the seed plants into monocotyledons and dicotyledons. See illustration the body of a seed plant (common bean) or vascular connection between shoot and root.

Cross-pollination The deposition of pollen from one flower to the stigma in another by artificial or natural means.

Cultivar A botanical variety that has originated under cultivation.

Cuticle 1. A continous, non-cellular layer (covering the surface of the epidermis of the aerial parts of plants) consisting of cutin and containing no cellulose. See illustration morphology of leaves.
2. A water-repellant outer membrane of plant parts.
3. In fungi, a differentiated tissue consisting of a single layer of hyphae covering the pileus or stipe.
4. A pellicle.
karmaxul Reviewed by karmaxul on . Botany definitions Great link for terms and definitions ( a ten minute read, a couple have nothing to do with plants) http://ecoport.org/ep?SearchType=earticleResourceView&earticleId=127&resource=Glossary One love c Rating: 5