| A | B |
|---|
| Absorption | The intake of water, gases, nutrients or other substances by plants. |
| Accumulation | To gather or collect. |
| Acid | A substance containing hydrogen that dissociates to form hydrogen ions when dissolved in water. Term applied to any substance with a pH less than 7.0. |
| Acidity | Measure of hydrogen ions in a solution |
| Achene | Any small, dry fruit having but one seed whose pericarp does not burst when the fruit is ripe. |
| Aeration | The process by which air in the soil is replenished by air from the atmosphere. |
| Aerobic | Pertaining to organisms that grow only in the presence of oxygen, as bacteria in a properly prepared compost. |
| Aeroponics | A system of hydroponics that involves misting of the roots with a nutrient solution. |
| Aesthetic | Pertaining to a sense of beauty or to aesthetics. |
| Aggregate Culture | A hydroponic system that uses a media to absorb the nutrient solution and hold it for the plant. |
| Agribusiness | A term referring to the full scale of operations related to the business of agriculture. It connotes the interrelationships of farming, farm services, soil science, agronomy, land grant universities, county extension services, state and federal experiment stations, soil and water conservation services, plant and animal nutrition, plant and animal protection, transportation, finance, and marketing. |
| Agricultural Education | Agricultural Education prepares students for successful careers and a lifetime of informed choices in the global agriculture, food, fiber and natural resources systems. |
| Agriculture | The broad industry engaged in the production of plants and animals for food and fiber, the provision of agricultural supplies and services, and the processing, marketing, and distribution of agricultural products. |
| Agronomy | The specialization of agriculture concerned with the theory and practice of field-crop production and soil management. The scientific management of land. |
| Alkaline | A chemical term referring to basic reaction where the pH reading is above 7, as distinguished from acidic reaction where the pH reading is below 7. |
| Allele | The alternative forms of genes having the same place in homologous chromosomes which influence the development of alternative traits or characters. |
| Anaerobic | Living or active in the absence of free oxygen. |
| Anaphase | The phase in mitosis when the cromatids separate and move toward opposite poles. In meiosis, the paired chromosomes move apart. |
| Anatomy | The branch of biology that deals with the structure of organisms. |
| Animal Pest | Any animal out of place. |
| Animal Science | Agriculture which deals with livestock and the processing of the products derived there from. |
| Annuals | Plants living one year or less. During this time the plant grows, flowers, produces seeds, and dies. |
| Anther | The saclike part of the stamen on seed-producing plants which develops and contains the pollen. |
| Anaphase | The phase in mitosis when chromatids separate and move toward opposite poles. In meiosis, the paired chromosomes move apart. |
| Apical | Relating to the apex or tip of shoots and roots. |
| Arboriculture | Cultivation of woody plants, particularly those used for decoration and shade. |
| Arthropod | A phylum or division of the animal kingdom; includes insects, spiders, and Crustacea; characterized by a coating which serves as an external skeleton and by legs with distinct movable segments or joints. |
| Aquaculture | Underwater agriculture, commonly called fish farming, that includes ordinarily the raising of water animals such as fish and shrimp, but which also includes the growing of water vegetation such as kelp. |
| Bacteria | Single-celled microorganisms; some cause human, animal, or plant diseases; others are beneficial. |
| Bacterium | A single-celled microscopic organism with cell walls and no chlorophyll. |
| Bark | The exterior of a woody stem containing phloem tubes and usually some bast fibers. |
| Bark Graft | A method of joining plants in which the scion is inserted between the bark and the xylem of the stock. |
| Base | A substance which gives off hydroxyl ions when dissolved in water, as contrasted with an acid, which gives off hydrogen ions. |
| Base | Botany, the part of a leaf or branch attached to a stem or trunk. |
| Bedrock | Unweathered hard rock that lies directly beneath the soil layers or beneath superficial geological deposits, such as glacial drift. |
| Berry | Any small pulpy fruit, as the raspberry, strawberry, ect; usually edible. |
| Biennial | A plant that lives for two years and then dies. |
| Binomial System | A two-name system for naming plants. |
| Biofuel | Broadly defined as solid, liquid, or gas fuel derived from recently dead biological material. |
| Biological Control | A method of pest control by the use of predatory insects, fungi, or viruses; as contrasted to control by chemical pesticides. |
| Biotechnology | Technology concerning the application of biological and engineering techniques to microorganisms, plants, and animals, sometimes used in the narrower sense of genetic engineering. |
| Biotic Potential | The maximum reproductive power or ability. The inherent ability of an organism to reproduce and survive in greater numbers. |
| Blade | The expanded portion of a leaf. |
| Boron | An element essential for plant growth. The original source of boron is tourmaline, but available forms are from soil organic matter. |
| Botanical Name | The scientific name of plants, which includes the genus and species. |
| Botany | The science of plants. |
| Bud | A protuberance containing miniature leaves or flowers, located terminally or laterally on a stem. |
| Budding | A form of grafting whereby a bud from a parent plant is placed in a normal position on the cambium of the stock. |
| Bulb | The subterranean bud of some plants, which has short stem overlapping, membrane-like leaf bases, as in onions and tulips. It stores food for reproduction and represents the inactive stage of the plant. |
| Calcium | Ca; a chemical element present in variable amounts in all soils. It is essential for plant and animal growth and is the principal mineral element in bones. |
| Calyx | The outer, usually green, leaflike parts of a flower. |
| Cambium | The actively growing cells between the bark and the wood in a tree or shrub. They give rise to secondary xylem and phloem of dicotyledonous stems. |
| Career | An occupation or profession followed as one’s lifework. |
| Career Development Events | Activities developed to replicate skills required for future careers. Participants apply the skills and knowledge learned in the classroom to practical experiences. Activities are usually local, regional, and national competitive events open to all FFA members. |
| Carpel | One of the units composing a pistil or ovary. A simple pistil has one carpel, while a compound pistil has two or more united carpels. |
| Cell | The ultimate functional unit of an organic structure, plant, or animal. It consists of a microscopic mass of protoplasm which includes a nucleus surrounded by a membrane. In most plants, it is surrounded by a cell wall. |
| Cell Membrane | Also called the plasma membrane, or plasmalemma. A selectively permeable, limiting membrane surrounding the protoplasm. |
| Cell Wall | The membranous covering of a cell secreted by the cytoplasm in growing plants. It consists largely of cellulose, but may contain chitin in some fungi and silica in some algae. |
| Centrosome | A minute protoplasmic body sometimes held to be the dynamic center of mitotic activity. |
| Cereal | Any grass grown for its edible grain. |
| Chemical Control | The application of herbicides or pesticides for the control of weeds and insects in crops. |
| Chlorine | Cl; a heavy gas used in very small amounts for the growth of plants. |
| Chlorophyll | A substance present in all green plants; it evidences itself as the green coloring in leaves. Chlorophyll transforms light energy from the sun into chemical energy for the manufacture of plant food from carbon dioxide, water, and essential soil minerals. This process is called photosynthesis. |
| Chloroplast | Minute objects within plant cells which contain the green pigment, chlorophyll. |
| Chlorosis | Yellowing or whitening of normally green leaves caused by lack of nutrients, air pollution, or diseases. |
| Chromatography | A technique for identifying the components of chemical mixtures separated by preferential adsorption on an adsorbent medium. |
| Chromosome | A microscopic, dark-staining body, visible in the nucleus of the cell at the time of nuclear division, which carries the genes, arranged in linear order. Its number in any species is usually constant, and it serves as the bridge of inheritance, i.e., the sole connecting link between two succeeding generations. |
| Class | A division of the plant or animal kingdom lower than a phylum and higher than an order; e.g., the class insect. |
| Classification | The forming, sorting, apportioning, grouping, or dividing of objects into classes to form an ordered arrangement of items having a defined range of characteristics. |
| Clay | A size term denoting particles, regardless of mineral composition, with diameter less than 2 microns. |
| Cleft Graft | A simple method of grafting in which large trees are used for stock. The branch is sawed squarely across and split lengthwise, and two scions are inserted into the cleft next to the cambium layer. |
| Climate | The long-term average weather conditions. |
| Coleoptile | The first leaf of a germinating monocot. Sheaths the succeeding leaves. |
| Commodity | Any unprocessed or partially processed good, as a grain, fruit or vegetable, or precious metal. A transportable resource product with commercial value; all resource products that are articles of commerce. |
| Compost | Organic residues or their mixture, such as peat, manure, or discarded plant material and soil, placed in a pit or enclosure, moistened, and allowed to become decomposed. Sometimes lime and chemical fertilizers are also added. Used as a fertilizer. |
| Compound Leaf | A leaf composed, usually, of two or more leaflets. |
| Complete Flower | A flower containing sepals, petals, stamens, and at least one pistil. |
| Conductivity | The property or power of conducting heat, electricity, or sound. |
| Conductivity Tester | An electronic device used to measure the electrical conductivity. |
| Conifer | A cone-bearing tree. |
| Converted Wood | Wood that has been mechanically or chemically changed. |
| Cool-Season Crop | Vegetables that thrive best in the cool season, such as cabbage, English peas, lettuce, or spinach. |
| Copper | Cu; a metallic element found in soils at 1 to 50 parts per million, and in plants up to 100 parts per million. It is necessary for all animal and plant life. High soil phosphorus, zinc, and molybdenum can induce copper deficiency in plants. Also, high copper can reduce plant uptake of phosphorus, iron, zinc, and molybdenum. |
| Corm | Enlarged fleshy base of a stem, bulblike but solid, in which food accumulates. |
| Corolla | In flowering plants, the inner circle or second whorl of floral envelope; if parts are separate, they are petals. |
| Cortex | The outer layer or region of any organ. |
| Cotlyedon | The first leaf to be developed by the embryo in seed plants. Also called seed leaf. |
| Crop | Any product of the soil. In a narrow sense, the product of a harvest obtained by labor, as distinguished from natural production or wild growth. |
| Cross Pollination | Transfer of pollen between plants that are not of identical genetic material. |
| Cubic Measurement | A system for the measurement of volume or space in cubic units. |
| Cultivar | A cultivated variety. A group of cultivated plants that are distinguished by any significant character and that retain their distinguishing features when reproduced sexually or asexually. |
| Cultivation | The planting, tending, harvesting, and improving of plants. |
| Cultural Control (Cultural Practices) | The use of production practices typically used to improve plant growth and yield by controlling pests. |
| Cutting | Any part that can be severed from a plant and be capable of regeneration. |
| Cut Flowers | A flower that has been harvested by cutting it off with the stem attached. |
| Cytoplasm | The living substance within a plant or animal cell excluding the nucleus. |
| Day-Neutral Plant | A plant in which the flowering period or some other process is not influenced by length of daily exposure to light. |
| Deciduous | Pertaining to a woody plant whose leaves fall at the end of the growing season |
| Deficiency | An insufficiency in reference to amount, volume, proportion, etc.; a lack; a state of incompleteness. |
| Dendrochronology | Study and matching of tree rings with the object of dating events in the recent past. |
| Density | Mass per unit volume. |
| Deposition | The addition of sediment, as by flowing water. |
| Diastase | An enzyme that converts starch to maltose. |
| Dicot (Dicotyledon) | Plant whose seeds have two cotyledons or seed leaves, such as beans. |
| Dichotomous | Forking regularly and repeatedly, the two branches of each fork usually essentially equal. |
| Differentiation | The development or growth of a cell, organ, or immature organism into a mature organism. |
| Dioecious | A plant that produces flowers that have either stamens or pistils, but not both on the same plant. |
| Diploid | Having one genome comprising two sets of chromosomes. Somatic tissues of higher plants and animals are ordinarily diploid in chromosome constitution in contrast with the haploid (monoploid) gametes. |
| Disease | Any deviation from normal state of health in plants, animals, or people which temporarily impairs vital functions. It may be caused by viruses, pathogenic bacteria, parasites, poor nutrition, congenital or inherent deficiencies, unfavorable environment, or any combination of these. |
| Dissolved Oxygen | The amount of oxygen found in water or solution. |
| Division | Propagation of plants by cutting them into sections as is done with plant crowns, rhizomes, stem tubers, and tuberous roots. |
| Dominant Gene | A gene that prevents its allele from having a phenotypic effect. |
| Dormancy | A physiologic state where the seed embryo is incapable of growth; a state when the metabolic processes are slowed. Especially applies to respiration. |
| Drainage | The removal of surplus ground or surface water by artificial means. |
| Drip Irrigation | Watering plants so that only soil in the plant’s immediate vicinity is moistened. Water is supplied from a thin plastic tube at a low flow rate. |
| Drupe | A single-seeded, fleshy fruit that does not split open, e.g., cherry, peach, plum, or olive. Also called a stone fruit. |
| Egg | The reproductive body produced by a female organism: in animals, the ovum; in plants, the germ cell, which after fertilization, develops into the embryo. |
| Electrical Conductivity | A measurement used in hydroponics used to determine the amount of nutrient in solution that is available to plant. |
| Elevation | The altitude of a place above sea level or ground level. |
| Embryo | Any organism in its earliest stages of development. |
| Emergence | The appearance of the first leaves of the crop plant above the ground. |
| Endocarp | The inner layer of a multiple-layered pericarp, e.g., the shell of a cherry stone. |
| Endoplasmic Reticulum | Structure extending throughout the cytoplasm of a cell. It functions in the transport of cell products and as a surface for protein synthesis by the ribosomes. |
| Endosperm | The nutritive portion in some seeds that originates in the embryo sac, but that is outside the embryo. |
| Enzyme | A large complex protein molecule produced by the body that stimulates or speeds up various chemical reactions without being used up itself; an organic catalyst. |
| Epicotyl | The part of the axis of an embryo above the region of attachment of the cotyledons. |
| Epicarp | The outermost layer, or exocarp, of a fruit. |
| Epidermis | The cellular layer of an organism; the outer skin. |
| Eradicate | To destroy or abolish, as a disease, insect, or weed pest. |
| Erosion | The group of processes whereby earthy or rock material is worn away, loosened or dissolved and removed from any part of the earth’s surface. |
| Eukaryote | Genetic information or DNA contained in the nucleus like most organisms. |
| Evaporation | The changing of a liquid into a gas. |
| Evapotraspiration | That part of the root zone moisture that is consumed by evaporation and transpiration combined, including all water consumed by plants plus the water evaporated from bare land and water surface. |
| Exocarp | The outer skinlike region of the fruit pericarp. |
| Family | A group of closely related genera. |
| FFA | A national youth organization for students interested in agriculture. The official name is the National FFA Organization. In 1988, the National FFA Organization changed its original name of Future Farmers of America to reflect the expanding career field of Agricultural Education. |
| Fertilization | Union of pollen with the ovule to produce seeds. |
| Fertilize | To supply the necessary mineral and organic nutrients to soil or water to aid growth and development of plants. |
| Fertilizer | Any organic or inorganic material added to soil or water to provide plant nutrients and to increase the growth, yield, quantity, or nutritive value of the plants grown therein. |
| Fiber Crop | Crop grown for its fiber, as cotton and flax. |
| Fibrous Root System | A root system that is comprised of profusely branched roots with many lateral rootlets. |
| Field Crops | Feed plants grown primarily for their seeds. For example, corn, wheat, oats, soybeans, etc. |
| Filament | The part of the stamen of a flower that is below the anther and supports it. |
| Firing | A change in color of the lower leaves of green plants usually attributed to a lack of plant nutrients or moisture deficiency. |
| Flood Irrigation | A system of irrigation consisting of adding water at the highest point in a field and allowing the water to cover the soil. |
| Floriculture | The cultivation of plants for their flowers |
| Flower | The reproductive structure of a seed-bearing plant, consisting of the male and/or female organs that are surrounded by one or two series of outer coverings (calyx and corolla). |
| Foliage Plants | A plant grown for the color and shape of its foliage; e.g., coleus. |
| Food | Anything which when taken into the body, nourishes the tissues and supplies body heat. |
| Food Science | Is a discipline concerned with all technical aspects of food, beginning with harvesting or slaughtering, and ending with its cooking and consumption. |
| Forage | That portion of the feed for animals that is secured largely from the leaves and stalks of plants, such as the grasses and legumes used as hays. |
| Forage Crops | Those plants or parts of plants that are used for feed before maturing or developing seeds (field crops). The most common forage crops are pasture grasses and legumes |
| Forcing | Bringing a plant to a specific stage in its development or to maturity earlier in the season than normal, by growing the plant in a greenhouse, under artificial light etc. |
| Forestry | The sciences, arts, and business practices of crating, conserving, and managing natural resources on lands designated as forests. |
| Fruit | Botanically, the matured ovary of a flower and its contents including any external part that is an integral portion of it. |
| Fungi | Plantlike organisms that have no chlorophyll; they get their nourishment from living or decaying organic matter. |
| Fungus | Organism with no chlorophyll that reproduces by means of structure called spores and usually has filamentous growth. |
| Furrow | The opening left in the soil after the furrow slice has been turned by the turning plow. |
| Furrow Irrigation | A method of irrigating in which water is run in small ditches, furrows, or corrugations, usually spaced close enough together for lateral penetration between them. |
| Gamete | A “sex-cell,” capable of uniting with another gamete to produce a cell (fertilized egg, or zygote) that in turn is capable of developing into a new individual. |
| Gene | The simplest unit of inheritance. Physically, each gene is apparently a nucleic acid with a unique structure. It influences certain traits. |
| Genetics | The science that deals with the laws and processes of inheritance in plants and animals. |
| Geotropism | A growth of shoots and roots of plants in response to the stimulus of gravity that is positive when the growth curvature is toward the center of the earth (as plant roots) or negative when the direction of growth is opposite to the pull of gravity (as plant shoots). |
| Genotype | The genetic constitution (gene makeup), expressed and latent, of an organism. Individuals of the same genotype breed alike. |
| Genus | A group of species of plants or animals believed to have descended from a common direct ancestor that are similar enough to constitute a useful unit at this level of taxonomy. |
| Germination | Sprouting of a seed, and beginning of plant growth. |
| Glucose | A common monosaccharide sugar that serves as the building block for many complex carbohydrates; blood sugar. |
| Goal | The result or achievement toward which effort is directed; aim; end. |
| Golgi (apparatus) | Cell organelle, important for glycosylation and secretion in cells. |
| Grafting | The inserting of a piece of one plant into another or the same plant with the intention that it shall grow there. |
| Grain | The seed of the cereal crops. (1)The seed of the cereal crops. (2) Commercially, or as listed on boards of trade, buckwheat, soybeans, and flaxseed, in addition to the cereals. |
| Grass | Nonwoody plants with hollow low jointed stems sheathed by narrow leaves, petal less flowers, and fruit resembling grain: includes bamboo, sugar cane, numerous grasses of lawn, field, and pasture, and the plants used as cereal crops. |
| Gravel | Accumulation of water-worn pebbles larger than two millimeters in diameter. |
| Greenhouse | Any of several different types of heated, glass- or plastic covered structures used for the growing of plants. |
| Green Manure | Crops such as legumes or grasses that are grown to be plowed or spaded into the soil to increase humus content and improve soil structure. |
| Ground Cover | Any vegetation that grows close to the ground, producing protection for the soil. |
| Growing Degree Day (GDD) | Used to estimate the growth and development of plants and insects during the growing season. |
| Gypsum | A mineral calcium sulfate, combined with water of hydration. In arid regions, large tonnages are used to treat sodic soils. |
| Haploid | In genetics, this is half the number of chromosomes that are usually present in the nucleus; occurs during reduction division. |
| Hardiness (Hardy) | Designating a plant that withstands various environmental factors, especially the low temperatures of a given region. |
| Harvest | To cut, reap, pick, or gather any crop or product of value, as grain, fruit, or vegetables. |
| Hay | Any leafy plant material, usually clover, fine-stemmed grasses and sedges, alfalfa, and other legumes, which has been cut and dried principally for livestock feeding. |
| Heredity | Genetic transmission of traits from parents to offspring. |
| Herbaceous | Not woody, dying back to the ground each year, such as rhubarb and asparagus (applied to a plant or stems). |
| Herbicide | Chemicals used to kill plants. They are used in contact with the seed, stem, or leaf of a plant. Herbicides are further divided into nonselective (kill all plants) and a selective (kill only certain species). |
| Heterozygous | Having two different genes at the same locus on a pair of homologous chromosomes. |
| Hierarchy | A system of persons or things ranked one above another. |
| Homozygous | Possessing identical genes with respect to any given pair or series of alleles. |
| Horizon | A layer of soil, approximately parallel to the surface, having distinct characteristics produced by soil-forming processes. |
| Hormone | Naturally occurring compound produced by the plant that affects plant growth. |
| Horticulture | The science of agriculture that relates to the cultivation of gardens or orchards, including the growing of vegetables, fruits, flowers, and ornamental shrubs and trees. |
| Humidity | Moisture in the atmosphere. |
| Hydrogen | A colorless, odorless, flammable gas, the lightest of the elements, that combines chemically with oxygen to form water. |
| Hydroponics | Growing plants in a nutrient solution and a media other than soil. |
| Hydroxyl | The ion OH-. |
| Hypocotyl | The short stem of an embryo seed plant, the portion of the axis of the embryo seedling between the attachment of the cotyledons and the radicle. |
| Imperfect Flowers | Flowers lacking either stamens or pistils. |
| Incomplete Flowers | A flower that lacks one or more of the four organs; sepals, petals, stamens, or pistils. |
| Incubation | Period of development during which the pathogen undergoes changes to a form that can penetrate or infect the new host plant. |
| Infection | Invasion of the tissues of the body of a host by disease-producing organisms in such a way that injury results; the presence of multiplying parasites, bacteria, viruses, etc., within the body of a host. |
| Inheritance | The transmission of genetic factors from parent to offspring. |
| Inoculation | The introduction of the pathogens to the host plant tissue. |
| Insect | An air-breathing animal that has a distinct head, thorax, and abdomen. Insects have one pair of antennae on the head, three pairs of legs, and usually two pairs of wings on the thorax. The opening of the reproductive organs is near the posterior end of the body. They may be harmful or useful depending upon their habits. |
| Integrated Pest Management (IPM) | An ecological approach to pest management in which all available necessary techniques are systematically consolidated into a unified program, so that pest populations can be managed in such a manner that economic damage is reduced and adverse side effects are minimized. |
| Internal Drainage | The relative degree of downward movement of water in a soil. Also called permeability. |
| Internode | The portion of a stem or other structure between two nodes. |
| Interphase | The period in the life of a cell between mitotic divisions. |
| Ion | An atom or a group of atoms carrying an electrical charge, which may be positive or negative. |
| Iron | Fe; a metallic element essential to people, animals, and plants; very common in some minerals, most rocks, and all soils. In plants, iron deficiency results in iron chlorosis. |
| Irrigation | The artificial application of water to soil for the purpose of increasing plant production. |
| Kernel | The portion of a seed contained within the seed coat. |
| Kingdom | Major divisions for living things; the plant kingdom and the animal kingdom. |
| Landscape | To beautify terrain as with plantings of trees, shrubs, and flowering herbs; with ornamental features, such as terraces, rock gardens, bog gardens, pools, walks, drives, etc. |
| Landscape Design | The profession concerned with the planning and planting of outdoor space to secure the most desirable relationship between landforms, architecture, and plants to best meet human needs for function and beauty. |
| Larva | The immature insect hatching from the egg and up to the pupal stage in orders with complex metamorphosis. |
| Lateral | A directional or positional term meaning away from the middle or toward the side. |
| Latitude | The angular distance, measured north or south from the equator, of a point on the Earth’s surface, expressed in degrees. |
| Latin | The language often used to name plants. |
| Layering | The method of propagating woody plants by covering portions of their stems or branches with moist soil or sphagnum moss so that they take root while still attached to the parent plant. |
| Leaching | The removal of soluble constituents from soils or other materials by percolating water |
| Leadership | An act or instance of leading; guidance; direction. |
| Leaf | A flattened outgrowth from a plant stem, varying in size and shape, usually green, which is concerned primarily with the manufacture of carbohydrates by photosynthesis. |
| Leaflet | A small, immature leaf. A separate division of a compound leaf. |
| Legume | A family of plants, including many valuable food and forage species, such as peas, beans, soybeans, peanuts, clovers, and alfalfa. With aid of symbiotic bacteria, they can convert nitrogen from the air to build up nitrogen in the soil. |
| Lifecycle | Life history; the changes in the form of life that an organism goes through. |
| Light | The form of radiant energy consisting of wavelengths that can be seen with the human eye. |
| Lime | Strictly, calcium oxide, CaO, but, as commonly used in agricultural terminology, calcium carbonate, CaCO3, and calcium hydroxide, Ca(OH)2, are included. Agricultural lime refers to any of these compounds, with or without magnesium carbonate, which are used as amendments chiefly for acid soils. |
| Loam | Soil that consists of less than 52 percent sand, 28 to 50 percent silt, and 7 to 27 percent clay, resulting in a soil texture ideal for gardening. |
| Long-Day Plant | A plant in which the flowering period or some other process is accelerated by a relatively long, daily exposure to light. |
| Long-Term Goal | A goal involving, maturing, or being in effect after a number of years. |
| Lysosome | An organelle bounded by a membrane and containing enzymes capable of breaking down proteins and other molecules. |
| Macronutrients | Includes primary plant nutrients N, P, and K; and secondary plant nutrients Ca, Mg, and S. |
| Magnesium | Mg; a white metal, essential for people and animals and for plant growth because it is a constituent of chlorophyll. |
| Manganese | Mn; a metallic element, found in soils from a mere trace to as much as 15 percent, but when present it is often in forms unavailable to plants. It is regarded as essential to normal plant growth and is often applied, usually as manganous sulfate, to soils deficient in this element. |
| Manure | Excreta of animals, dung and urine (usually with some bedding), used to fertilize land. |
| Margin | The edge, border, or borderline, as margin of a leaf. |
| Marketing | The act of buying and selling in a market. |
| Marketing Concept | A management philosophy that holds that all company planning begins with an analysis of consumer wants, and that all company decisions should be based upon the profitable satisfaction of consumer wants. |
| Marketing Plan | A written, detailed plan that outlines your specific strategies and goals to get customers to purchase your products or services. |
| Maturity (Maturation) | Becoming mature or ripe. |
| Media | Soil or soil like material in which plants are grown. |
| Medicinal | Pertaining to, or having the properties of a medicine. |
| Meiosis | Cell division early in the reproductive process, and in the formation of pollen and ovule. Each pair of chromosomes in the cell being divided separates, and one member of each pair goes to each of the two new cells formed. |
| Membrane | A thin, flexible sheet of vegetable or animal tissue; the thin protoplasmic tissue connecting, covering, or lining a structure, such as a cell of a plant or animal. |
| Meristem | Plant tissue capable of cell division and therefore responsible for growth. |
| Mesocarp | The seed of the cereal crops. |
| Mesophyll | The parenchyma tissue between the upper and lower epidermis of a leaf; the cells usually contain chloroplasts. |
| Metabolic | Designating the chemical changes that take place in living plant and animal cells whereby one compound is converted to one or more other compounds. |
| Metabolism | Physical and chemical process in an organism by which living matter is produced, maintained, and destroyed, and by means of which energy is made available. |
| Metamorphosis | A process by which an organism changes in form and structure in the course of its development, as many insects do. |
| Metaphase | The stage of cell division in which the chromosomes are arranged in an equatorial plate or plane. It precedes the anaphase stage. |
| Micronutrient | For plants; boron, chlorine, cobalt, copper, iron, manganese, molybdenum, and zinc. |
| Microorganism | An organism so small that it cannot be seen clearly without the use of a microscope; a microscopic or submicroscopic organism. |
| Micropropagation | A propagation technique that uses a single cell of the meristematic tissue of a plant to produce a new plant. The process is also known as cloning and tissue culture. |
| Midrib | The main vein of a leaf; located halfway between the two edges. It is a continuation of the leaf stalk. |
| Mitochondria | Cell organelles composed of an outer membrane and a winding inner membrane. A series of chemical reactions that occur on the inner membrane convert the energy of oxidation into the chemical energy of ATP. |
| Mitosis | Cell division involving the formation of chromosomes, spindle fibers, and the division of chromosomes by a process if longitudinal splitting. Each of the resulting daughter cells thus has a full set of chromosomes as distinguished from reduction division or meiosis, in which the daughter cells have half the somatic number. |
| Molybdenum | Mo; a gray metallic element, essential in very small amounts to the growth of plants, but usually present in sufficient amounts. Deficiencies have been discovered in a few highly acid soils. |
| Monocotyledon | Plant having a single cotyledon or seed leaf such as corn. |
| Monoecious | Plants that have male and female sex organs in different flowers on the same plant, such as cucumbers and squash. |
| Mottle | Color difference on a mass of moderately poorly drained soil. |
| Mollusk | Any invertebrate of the phylum Mollusca, having a calcareous shell of one or more pieces that wholly or partially enclose the soft, un-segmented body. Includes snails and slugs. |
| Morphology | A branch of biologic science that deals with the forms, rather than the functions, of plants and animals. |
| Mycoplasma | A microscopic bacterium like organism that lacks a cell wall and appears filamentous. |
| Natural Resources | The natural wealth of a country, consisting of land, forests, mineral deposits, water, etc. |
| Necrosis | Death of plant or animal cells of tissue, usually in localized areas. |
| Nectar | A sweet secretion of flowers of various plants, used by bees to store as honey. |
| Nematode | Microscopic, wormlike, transparent organisms that can attack plant roots or stems to cause stunted or unhealthy growth. |
| Neutral (pH) | Having neither acid nor alkaline qualities, pH of 7. |
| Nitrogen | N; a gas that occurs naturally in the air and soil, where it is converted into usable forms for plant use by bacteria and other natural processes. This nutrient is a constituent of proteins and is vital to plant growing processes. Nitrogen can be added to the soil in any of three fertilizer forms: as urea, ammonia, or nitrates. |
| Nitrogen Fixation | When molecular nitrogen biologically or chemically converts to organic combinations or forms available for biological processes. Biological fixation occurs with legumes, whereas chemical fixation involves the manufacture of ammonia. Legume roots convert nitrogen gas to nitrates by bacteria. |
| Node | The place upon a stem that normally bears a leaf or whorl of leaves; the solid constriction in the culm of a grass; a knoblike enlargement. |
| Nomenclature | A system of naming used to classify a group, such as the botanical names of plants. |
| Noninfectious Disease | Diseases caused by abiotic agents. |
| Nucleolus | A spherical body found within the nucleus of a eukaryotic cell. |
| Nucleus | The central portion of the cell protoplast surrounded by a very thin membrane. It consists of nucleoplasm and includes within itself variously arranged chromatin, nuclear sap, and nutritive substances. It is of crucial significance in metabolism, growth, reproduction, and the transmission of the determiners of heredity characters. |
| Nursery | Any place where plants, shrubs, and trees are grown either for transplanting or as grafting stocks. |
| Nut | An indehiscent, one-celled and one-seeded, hard and bony fruit, as the acorn of Quercus. |
| Nutrient | An element or compound in a soil that is essential for the growth of a plant. |
| Nutrient Flow Technique | A popular water culture technique where the nutrient solution is continuously flowing at the tips of the plants roots set in a medium. |
| Nymph | A stage in the development of some insects and related forms, immediately preceding the adult stage |
| Oil Seed | Any crop grown primarily for its oil content, such as soybeans, peanuts, cottonseed, and linseed (flaxseed). |
| Orchard | A grove of fruit or nut trees. |
| Order | In botanical classification of plants, a category in between class and family. |
| Organelle | The inside parts of a cell such as the Golgi apparatus, nucleus, ribosomes, microtubules, and storage particles. |
| Organic | Produced by plants and animals; of plant or animal origin. |
| Organic Matter | Matter found in, or produced by, living animals and plants, which contains carbon, hydrogen, oxygen, and often nitrogen and sulfur. |
| Organism | Any living individual whether plant or animal. |
| Osmosis | The flow of a fluid through a semi permeable membrane separating two solutions, which permits the passage of the solvent but not the dissolved substance. The liquid will flow from a weaker to a stronger solution, thus tending to equalize concentrations. |
| Osmotic Pressure | The hydrostatic pressure required to stop osmosis or prevent diffusion of molecules of a dilute solution from passing through the walls of a semipermeable membrane into a more-concentrated solution. |
| Ovary | The portion of the pistil or carpel of a flower that contains one or more ovules. |
| Overhead Irrigation | A system of irrigating a small acreage by sprinkling from overhead pipes. |
| Ovule | The body that, after fertilization, becomes the seed; the egg-containing unit of the ovary. |
| Palisade Cells (Layers) | Tissues just below the epidermis of the leaf of a plant; most photosynthesis takes place in the palisade layers. |
| Palmate | With three or more nerves, lobes, or leaflets radiating fanwise from a common basal point of attachment. |
| Parallel (Veined) | A leaf type that has veins running parallel to each other as in a blade of grass. |
| Parenchyma | Cells with thin cell walls and with large vacuoles. In leaves, parenchyma cells contain chloroplasts for photosynthesis. |
| Parent Material | The horizon of weathered rock or partially weathered soil material from which the soil is formed. |
| Pathogens | Disease causing organisms. |
| Peat | Fibrous, partly decayed fragments of vascular plants that retain enough structure so that the peat can be identified as originating from certain plants (e.g., sphagnum peat or sedge peat). |
| Ped | A unit of soil structure such as an aggregate, crumb, prism, block, or granule, formed by natural processes (in contrast with a clod, which is formed artificially by compression of a wet clay soil). |
| Penetration | Process of getting inside the plant, it may be an active or passive process. |
| Pepo | A berrylike fruit of large size, with a tough or very firm and hard outer wall that is developed from the receptacle, such as a watermelon, the cucumber, and the squash. |
| Perennial | A plant that lives for more than two years. |
| Perfect Flower | A flower with both stamens and a pistil or pistils. |
| Pericarp | The outer layer of the ovary wall around the seeds. It sometimes consists of three separate structural layers: the endocarp, the mesocarp, and the epicarp. |
| Perlite | A volcanic glass used in greenhouses as a synthetic soil mix. |
| Permeability | The capacity of soil or rock for transmitting a fluid. Degree of permeability depends upon the size and shape of the pores, the size, and shape of their interconnections, and the extent of the latter. |
| Peroxisome | In the plant cell, use oxygen to carry out catabolic reactions. |
| Pest | Anything, such as an insect, animal, or plant that causes injury, loss, or irritation to a crop. |
| Pesticide | A substance used to control insect, plant, or animal pests. Pesticides include insecticides, herbicides, fungicides, nematocides, and rodenticides. |
| Petal | A division of a flower inside the calyx; a unit of the corolla, consisting of petioles, which usually surrounds the pistils and stamens. |
| Petiole | The stem of any leaf. |
| pH | A numerical measure of acidity or hydrogen ion activity of a substance such as food or soil. The neutral point is pH 7.0. All pH values below 7.0 are acid and all above 7.0 are alkaline. |
| Phenotype | The observed character of an individual without reference to its genetic nature. Individuals of the same phenotype look alike but may not breed alike. |
| Phloem | Inner bark; the principle tissue concerned with the translocation of elaborated food produced in the leaves, or other areas, downward in the branches, stem, and roots. |
| Phosphorus | P; a chemical element found in soils in various mineral forms, but only small amounts are readily available to plants at any one time. It stimulates early growth and root development, and hastens grain maturity. |
| Photoperiod | Length of the light period in a day. |
| Photoperiodism | The reaction of plants to periods of daily exposure to light, which is generally expressed in formation of blossoms, tubers, fleshy roots, runners, etc. |
| Photosynthesis | Process by which green plants, using chlorophyll and the energy of sunlight, produce carbohydrates from water and carbon dioxide, release oxygen. |
| Phototropism | The response of a plant to the stimulus of sunlight in which the plant or its parts seem to turn to face the light. The parts of the plant receiving the direct rays grow more slowly and the plant appears to turn. |
| Phloem | Inner bark; the principle tissue concerned with the translocation of elaborated food produced in the leaves, or other areas, downward in the branches, stems, and roots. |
| Pinnate | Constructed somewhat like a feather, with the parts (e.g., veins, lobes, branches) arranged along both sides of an axis, as in pinnate venation. A pinnate leaf is compound, with the leaflets arranged on both sides of the rachis. |
| Pistil | The female element of a flower; composed of stigma, style, and ovary. |
| Pistillate | Designating a flower that has a pistil or pistils but lacks stamens; an imperfect flower. |
| Pith | The spongy center of exogenous plants. In the corn plant the pith fills the center cavity of the stalk and serves as a storehouse for moisture and food. |
| Plant | An organism distinguished from the animals in that it takes nutrients entirely in liquid solution, rather than in solid form. |
| Plantlet | Small plants or the tips of new plants. They are produced from stolons or runners. They may be rooted while still attached to the parent, or detached and placed in a rooting medium. |
| Plant Science | Is a branch of biology and is the scientific study of plant life and development. |
| Plumule | In a germinating seed plant, the primary bud that develops into the primary stem. In a dicotyledon, such as beans, it is located between the cotyledons. |
| Pod | Technically, a dry, many-seeded fruit that splits open, such as a pea pod or bean pod; a legume. |
| Pollen | The male element that carries the spores in the fertilization of the egg nucleus in the ovule of a flower. The pollen is borne by the anthers and is usually a yellowish, dustlike mass of separate grains. |
| Pollen Grain | The anther or male part of the flower produces pollen grains that are the male sex cells. |
| Pollen Tube | Tube formed following the germination of a pollen grain, when the grain resides on the stigma of a flower. The tube carries the male gametes to the ovule. |
| Pollination | The transfer of the pollen from the anther to the stigma of a flower, the first step in producing a fruit or seed. |
| Pollution | The introduction of harmful substances or products into the environment. |
| Pome | A fleshy fruit having several seeds instead of a stone, as apple, pear, and quince. |
| Porosity | Refers to the extent of voids or openings in the soil that exist between soil particles and soil peds or clods. These pores hold water and air for absorption by plant roots. About half of soil volume which is in a good physical condition for plant growth is pore space. |
| Potassium | K; the chemical element, an alkali metal, which occurs widely in minerals. Regarded as an essential plant nutrient, potassium is present naturally in some form in all soils but in extremely variable amounts, and is likely to be in largest amounts in clay soils and in least amounts in highly silicious soils and in peats. |
| Prefix | An affix; attached to the front of a word to produce a derivative word or an inflected form. |
| Prevention | To keep from occurring; stop. |
| Primary Nutrient | Nitrogen, phosphorus, and potassium. |
| Primary Root | The main descending axis of a plant; the pole of the embryo opposite the shoot. |
| Prophase | The first phase of cell division wherein many of the preparatory steps takes place, such as shortening and thickening of the chromosomes, division of the centromeres, disappearance of the nuclear membrane, and formation of the spindle. |
| Profile | A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers. |
| Prokaryotes | Cell with DNA not enclosed in the nucleus. |
| Promotion | The coordination of all seller-initiated efforts to communicate with potential customers. |
| Prophase | The first phase of cell division wherein many of the preparatory steps takes place, such as shortening and thickening of the chromosomes, division of the centromeres, disappearance of the nuclear membrane, and formation of the spindle. |
| Protoplast | A unit of protoplasm in one cell. |
| Protoplasm | The gelatinous, colloidal material of plants and animals in which all life activities occur. |
| Pumice | A porous or spongy form of volcanic glass. |
| Pupa | The stage between the larva and the adult in insects with complete metamorphosis, a non-feeding and usually inactive stage. |
| Radiant (Radiant Energy) | Energy transmitted in wave motion. Light. |
| Radiation | The process in which energy is emitted as particles or waves. |
| Radicle | The embryonic roots of seed plants. |
| Recessive | In genetics, a gene or trait which is masked by a dominant gene. |
| Research | All effort directed toward increased knowledge of natural phenomena and the environment and toward the solution of problems in all fields of science. This includes basic and applied research. Much of the agricultural productivity of the United States is directly the result of applying research. |
| Respiration | A chemical process that takes place in living cells whereby food (fats, carbohydrates, and proteins) is “burned” (oxidized) to release energy and waste products, mainly carbon dioxide and water. Living things use energy produced through respiration to derive vital life processes such as growth and reproduction. |
| Ribosome | A particle that lies along the endoplasmic reticulum and is composed of a protein portion and RNA. The site of protein synthesis. |
| Rhizomes | Elongate underground stems or branches of a plant which send off shoots above and roots below and are often tuber-shaped. These contain deposits of reserve food material and are used for vegetative propagation of plants. |
| Rock | Mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable quantities in nature. |
| Rockwool | Fibers made of natural or synthetic minerals used as a media for growing plants in a hydroponic system. |
| Rodent | A classification of mammals, mostly vegetarians, characterized by their single pair of chisel-shaped, upper incisors. |
| Root | The lower portion of a plant bearing neither leaves nor reproductive organs which mostly develops underground and anchors the plant in the soil. It bears the root hairs, which absorb water and mineral nutrients. |
| Root Cap | The extreme tip of the root consisting of a group of cells that slough off and are replaced as the tip moves through the soil. It protects the growing region of the root. |
| Root Crops | Any of a number of field and garden crops whose underground roots are used as food for people and animals, as turnips, beets, carrots, and sweet potatoes. |
| Root Hair | A hair like growth on an epidermal cell of the root. It absorbs water and mineral nutrients for the plant. |
| Runoff | Something that drains or flows off, as rainwater. |
| Runner | A lateral, aboveground shoot (stolon) of certain plants; e.g., strawberries, which roots forms young plants at some of the nodes, aiding in propagation. |
| Saline (Soil) | A soil containing soluble salts in such quantities that they interfere with the growth of most crop plants. |
| Salinity | The quantity of saltiness in seawater or freshwater, most commonly expressed in parts of dissolved salt per 1,000 parts of water. |
| Samara | A single-seeded, winged fruit, whose wing helps in seed dissemination, like that of the maple, ash, and elm. |
| Sand | In soil science, a group of textural classes in which the particles are finer than gravel but coarser than silt, ranging in size from 2.00 to 0.5 millimeters in diameter. It is the textural class of any soil that contains 85 percent or more of sand and not more than 10 percent of clay. |
| Scion | An un-rooted portion of a plant (scion wood) having one or more buds, used for grafting or budding on to rootstock (rooted portion of plant). |
| Secondary Nutrient | Calcium, magnesium, and sulfur are the secondary nutrient elements, so called because they are essential to plant growth in lesser quantity that the primary nutrients nitrogen, phosphorus, and potassium, and are in greater quantity than the micronutrients. |
| Secondary Root | Branches of the primary root are often fibrous and referred to as secondary roots; become the permanent roots of many monocotyledons. |
| Seed | The embryo of a plant; also kernels of corn, wheat, etc., which botanically are seed like fruits as they include the ovary wall. |
| Seed Coat | The hard outer layer of a seed; the protective covering, or integument. Also called testa. |
| Seedling | The early growth stage of a plant grown from seed as it emerges above the ground surface. |
| Self-Pollination | The transfer of pollen from the anther to the stigma of the same flower or to flowers of the same plant or other plants of identical genetic material such as apple varieties, clones of wild blueberries, etc. |
| Sepal | One of the separate units of a calyx, usually green and foliaceous. |
| Separation | A form of propagation by which plants that produce bulbs or corms multiply. |
| Sexual Propagation | Producing plants from seeds. |
| Shell | The hard outer covering of a fruit or seed, as a nut shell, etc. |
| Short-Day Plant | A plant in which the flowering period or some other process is accelerated by a relatively short daily exposure to light. |
| Short-Term Goal | A goal lasting a relatively short time. |
| Side Graft | A method of grafting used outdoors and in the greenhouse. A rather long downward diagonal cut is made in the stock and a scion with a lower end shaped into a thin wedge is inserted within its bark, the cut side being kept close to the wood. |
| Silage | A crop that has been preserved in moist, succulent condition by partial fermentation in a tight container (i.e., silo) above or below the ground. The chief crops stored in this way are corn, sorghum, and various legumes and grasses. The main use of silage is in cattle feeding. |
| Silt | Small, mineral, soil particle, ranging in diameter from 0.05 to 0.002 millimeters. |
| Simple Leaves | Leaf blades consisting of one unit. |
| Sodic Soil | A soil with an exchangeable sodium percentage of 15 percent or greater and a pH between 9.5 and 10.0. |
| Soil | The mineral and organic surface of the earth capable of supporting upland plants. It has been (and is being) formed by the active factors of climate and biosphere exerting their influence on passive parent material and topography over neutral time. |
| Soil Profile | A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers although these may not be separated by sharp lines of demarcation. |
| Soil Structure | The arrangement of primary soil particles into compound particles or aggregates that are separated from adjoining aggregates |
| Soil Texture | The relative proportion in a soil of the various size groups of individual soil grains. |
| Species | In the naming of plants and animals, Latin is used. Each kind of plant or animal can be identified by genus (plural, genera) and species (both singular and plural); e.g., the generic name (genus) of corn is Zea and the species name is mays. |
| Spectrometer | An optical device for measuring wavelengths of light. |
| Spectrum | The band or series of colors, together with invisible extensions, produced by dispersion of radiant energy, as by a prism. |
| Stamen | The organ of a flower which bears the pollen (microspores) consisting of the stalk (filament) and the anther. |
| Staminate | Designating a flower that has stamens but no pistil and hence is imperfect. |
| Starch | A kind of carbohydrate manufactured by plants and stored in the seeds, roots, and fruit as a reserve energy supply. |
| Stem | Stalk, trunk, branch of a plant. Can be vertical or horizontal. |
| Stigma | The receptive surface of the female organ of a flower that receives the pollen. |
| Stock | Plant or plant part upon which a scion is inserted in propagation. |
| Stolon | A horizontal stem on the surface of the ground where it propagates vegetatively by forming new roots and shoots at the nodes. |
| Stomata | Openings in the epidermal layer of plant tissues which leads to intercellular spaces. These small openings may open or close, depending on climatic conditions, by means of guard or bullform cells, etc., and are necessary to photosynthesis, transpiration, etc. Also called breathing pores. |
| Stratification | The rest period that some seeds must have before they will germinate; generally the seeds must be exposed to a chilling temperature during this period before they will germinate. |
| Stunt | To check or hinder the growth or development of an animal or plant. |
| Style | In the pistil of a flower, the part between the ovary and the stigma; if the style is lacking, the stigma is sessile on the ovary. |
| Sucker | A secondary shoot which develops from the root, crown, or stem of a plant. |
| Suffix | An affix added to the end of a word or stem serving to form a new word. |
| Sulfur | S; an elementary, yellow mineral, insoluble in water, easily fusible and inflammable. One of the secondary but important elements in soil fertility and used in relatively large amounts by most plants, it is an important constituent of both protein and protoplasm. |
| Supervised Agriculture Experience (SAE) | Individualized program of study for students interested in learning skills and knowledge related to agriculture. Students develop and implement a real-life project in one of four areas: exploration of agriculture, entrepreneurship, job placement, or research. |
| Taproot | The primary descending root, usually conical, of a plant from which lateral branching roots may develop; e.g., as in carrots and alfalfa. |
| Taxonomist | A person who identifies and classifies plants often providing the proper name for the plant. |
| Taxonomy | The science of classification of organisms and other objects and their arrangement into systematic groups, such as species, genus, family, and order. |
| Telephase | The phase of cell division between anaphase and the complete separation of the two daughter cells; includes the formation of the nuclear membrane and the return of the chromosomes to long, threadlike and indistinguishable structure. |
| Temperature | The amount of heat or cold measured in degrees on different scales, as Fahrenheit or Centigrade. |
| Testa | The outer coat of a seed. |
| Texture | The relative portions of sand, silt, and clay particles in a mass of soil. |
| Tillage | The mechanical manipulation of soil for any purpose; but in agriculture it is usually restricted to the modifying of soil conditions for crop production. |
| Tiller | An erect shoot arising from the crown of a grass. |
| Tip | The end of a branch, twig, etc. |
| Tissue | Groups of cells working together to carry out a common function, such as muscle tissue, connective tissue, and epithelial tissue. |
| Ton (Tonnage) | Unit of weight equivalent to 2000 pounds. |
| Topography | Slope of the land and the position on the landscape, such as the top of a hill, a hillside, or the foot of a slope. |
| Trace Element | Any of certain chemical elements necessary in minute quantities for optimum growth and development of plants and animals. |
| Transformation | Change in form, appearance, nature, or character. |
| Translocate | The transfer of the products of metabolism, etc., from one part of a plant to another. |
| Translocation | To move or transfer from one place to another; cause to change location; displace. The transfer of the products of metabolism, etc., from one part of a plant to another. |
| Transpiration | The process by which water vapor is released to the atmosphere by the leaves or other parts of a living plant. |
| Transpiration Pull | A tension within a plant which is generated by transpiration and exerts a pulling force. Transpiration pull is a major factor in the rise of water in plants. |
| Treatment | To deal with (a disease) in order to relieve or cure. |
| Tropism | A growth reaction of a plant to various external or internal stimuli, such as phototropism, the increased growth toward or away from light; geotropism, growth in response to gravity; chemotropism, plant response to chemicals; hydrotropism, plant response to water. |
| Tuber | Thickened or swollen underground branch or stolon with numerous buds (eyes). Thickening occurs because of the accumulation of reserved food; e.g., Irish potato, Jerusalem artichoke. |
| Turf | A close-growing, well-knit, usually fine-leaved growth of a grass, mixture or grasses, or other plant species, which is best maintained by mowing, fertilizing, and watering so as to present a pleasing appearance. It is useful for lawns, golf courses, horse-racing tracks, and athletic fields. |
| Turgid | Swollen, or tightly drawn, said of a membrane or covering expanded by pressure from within; e.g., growing plants have turgid cells. |
| Turgor | The distension of the cell wall and protoplasmic layer of plants by fluids. It is essential to growth. |
| Vacuole | A cavity that is within the cytoplasm, filled with a watery fluid, bound by a membrane, and considered to be nonliving. |
| Valley | An elongated depression between uplands, hills, or mountains. |
| Variety | A group of related plants or animals that differs from other similar groups by characteristics too trivial or inconstant to be recognized as a species; often any category of lower rank than a species. |
| Vascular System | The fluid-conducting tissues of a plant including both xylem (water-conducting) and phloem (food-conducting) tissues. |
| Vascular Tissue | The fluid-conducting tissues of a plant including both xylem (water conducting) and phloem (food-conducting) tissues. |
| Vegetable | The edible part of an herbaceous plant. |
| Vegetation | Any group or association of plants; the sum of vegetable life; plants in general. |
| Venation | The arrangement of the veins in a leaf. |
| Ventilation | The act of circulating air so as to cool or freshen the air of. |
| Vermiculite | A mineral, or minerals, classified with the micas, which with treatment at high temperatures, expands into scales and becomes a loose, absorbent mass. |
| Vernalization | Seed treatment in which the germinating seed is held in artificial darkness, at low temperatures, for a fixed period to induce early flowering and fruiting when sown. |
| Viability | The capacity of seeds to germinate. |
| Viroid | A virus like particle that lacks the outer protein coat of a virus particle. |
| Viruses | Submicroscopic, sub cellular particles that require a host cell in which to multiply. |
| Warm-Season Plant | Designating a plant that thrives best when the temperature is regularly quite high; e.g., okra, cotton, grain sorghum. |
| Water Culture | A hydroponic system where the roots are in consistent contact with the nutrient solution where the media may not be as absorbent. |
| Wavelength | Distance between consecutive crests of waves. |
| Weathering | Atmospheric action on rock surfaces producing decomposition, disintegration, or alteration of rocks at or close to the earth’s surface. |
| Weed | A plant out of place. A plant whose usefulness is not recognized or which is undesirable because of odor, spines, prickles, or poisonous characteristics. |
| Whip Graft | A method of grafting, usually at the collar or on the roots of small seedling trees, as in the propagation of nursery stock, or in joining small branches as in topworking. The stock is cut off with a long slanting cut, in which a vertical slit, forming a kind of tongue, is made. The cuts on the lower end of the scion are made to complement those on the stock so that it is possible to insert the tongue of one in the slit of the other. |
| Wilt | The temporary or transient loss of turgidity in a plant, caused by a rate of transpiration in excess of the rate of absorption of water. |
| Wilting Point | The minimal point of soil moisture the plant requires not to wilt. |
| Xylem | The “plumbing” system that conducts water and dissolved mineral up the stems from the roots. It is part of the fibrovascular system of a vascular plant that includes the nonliving tracheids and vessels, the immediately associated living parenchyma cells, and the supporting and protecting wood fibers. In plants with woody stems, the xylem lies inside the cambium. Xylem is the tissue that makes up most, if not all, of the lumber wood and wood products of commerce. |
| Zinc | Zn; a metallic chemical element, one of the micronutrient elements in soils, essential for both plant and animal growth. |
| Zygote | A fertilized ovum or egg, it is the diploid cell formed from the union of the sperm with an ovum. |
