Appendix 8
Glossary
Abscission. A layer of cells that forms at the base of a fruit or leaf stalk where it is attached to the stem.
Acid soil. Any soil with a pH reading below 7.0 on a scale of 1 to 14. The lower the reading, the more acid the soil.
Alkaline soil. Any soil with a pH reading above 7.0 on a scale of 1 to 14. The higher the reading, the more alkaline the soil.
Anther. The pollen bearing part of a flower's male sexual organ. In the tomato, this is also referred to as the anther cone.
Aphid. A small sucking insect, usually pale green, gray or black, but also yellow pink or lavender, less than a quarter inch long, pear shaped. These appear in great numbers at the tender growing points of an attacked plant. They are most easily recognized by the fact that they secrete a sticky fluid called honeydew, and by the ants that will often be found at the same site, appearing to "tend" the aphids. Aphids can be controlled by knocking them from the plants with a hard stream of cold water or by spraying with insecticidal soap or an insecticide.
Axil. The upper, or inside, angle between a leaf stalk and the stem where new buds and new stems may arise.
Bacillus thurigensis. (See Bt.)
Bacteria. Microscopic, one-cell organisms which reproduce by fission, lacking chlorophyll, and causing diseases in tomatoes such as bacterial wilt, bacterial spot, and bacterial speck.
Biological control. Using one or more living organisms to help control a pest.
Blossom-end rot (BER). A leathery black spot at the blossom caused by a deficiency in calcium. Tomato plants that suffer from water stress or extreme fluctuations in moisture are prime candidates for blossom-end rot. Other conditions that make tomatoes susceptible are cool, humid weather, compacted soil and high levels of ammonia or potassium in the soil. Prevent BER by keeping soil evenly moist and well mulched. Add lime if you have an acidic pH and low calcium; add gypsum if your soil is alkaline and calcium-deficient.
Bt. Bacillus thurigensis. A biological insecticide that kills caterpillars, but is harmless to the environment and higher warm blooded animals.
Calyx. Collective name for all the sepals of a tomato blossum. These are green modified leaves which surround and protect the male and female parts of a tomato flower bud.
Compost. Fully or partially decayed vegetable matter with the appearance of soil that is used to improve both the texture and fertility of garden soil.
Corolla. The collective name for all the yellow petals of a tomato flower.
Cotyledon(s). The seed leaves encased within the seed, which are present before germination, and are distinct from true leaves, which develop after germination.
Cover crop. Usually a grass or legume planted to control weeds and erosion that is turned under while green to add organic matter and nutrients to the soil.
Cross pollination. The fertilization of the ovary on one plant with pollen from another plant, producing a progeny with a new genetic makeup distinct from either parent.
Crown. The base of a plant, where the stem and root join, usually at ground level.
Cultivar. A variety strictly raised through horticultural processes, rather than in nature. Cultivars are often mistakenly referred to as varieties. (See varieties.)
Cutting. A piece of leaf, stem or root removed from a plant and prompted to develop into a new plant, genetically identical to the parent plant.
Cutworm. The larvae of several species of moths that pupate just beneath the surface of the soil. While in the larval stage, they emerge at night and "cut down" seedlings, then devour them, leaving no evidence beyond the severed stem. Control is attempted by putting one-inch-tall collars around the stem of newly set transplants so that the cutworms cannot get to them.
Damping off. The result of a number of fungal diseases which attack seedlings, causing the stem to wither at the soil line, collapsing the plant. There is no good cure for affected plants, but any remaining plants can be saved by removing all the diseased material and moving the seedlings to a warm, bright, airy location. Proper thinning and avoidance of over watering, especially during cloudy periods, is the best preventative.
Determinate. A plant growth habit in which stems stop growing at a certain height and produce a flower cluster at the tip. Determinate tomatoes, for example, are short, early, have a concentrated fruit set, and do not require staking.
Drench. A pesticide or fertilizer treatment usually dissolved in water that is then applied to the soil, or medium, in which a plant is growing.
Emasculation. The removal of the anther cone – the portion of the tomato blossom which contains the pollen – so as to prevent self-pollination.
F1 Hybrid. A cross of two purebred inbred lines, to produce plants of exceptional vigor and uniformity.
Fibrous root. A root system that branches in all directions, often directly from the crown of the plant, rather than branching in a hierarchical fashion from the tap root, a central root. Fibrous roots usually develop when the tap root has been broken during transplanting.
Foliar feeding. Fertilization of plants through the application of a fine mist containing diluted soluble fertilizer, such as fish emulsion or kelp, directly to the leaves.
Fungicide. Any material capable of killing fungi. Sulfur and copper sulfate are two common mineral fungicides. There are also many contact and systemic fungicides available.
Fungus. A microscopic organism lacking chlorophyll and the ability to manufacture its own food, with a body of spider web-like filaments.
Germination. The initial sprouting of a seed.
Growing degree days (GDD). The number of degrees that the average temperature is above a baseline value. Every degree that the average temperature is above a baseline value becomes a growing degree day. Used by horticulturists and growers to predict the date that a crop will reach maturity.
Hardening off. The process of gradually exposing seedlings started indoors to outdoor conditions before transplanting.
Heat stress. Injury resulting from high temperatures. May be caused during exceptionally hot weather when transpiration rates are limited and the plant cannot cool itself adequately.
Host. A plant that is attacked by a pathogen.
Hybrid. A plant resulting from a cross between two distinct parents.
Indeterminate. A plant growth habit in which stems keep growing indefinitely in length. Indeterminate tomatoes, for example, are tall, late, and require staking for improved yield. They may have tomatoes present at all stages of development on the vines.
Infection. When a pathogen is established in a host.
Insecticidal soap. A specially formulated soap that is only minimally damaging to plants, but kills insects primarily causing their outer shell to crack, which causes the insect's interior organs to dry out.
Insecticide. Any material that kills insects. There are numerous botanical and mineral powders that are toxic to insects, as well as biodegradable chemicals such as insecticidal soaps.
Internode. The part of a stem that is in-between nodes. (See node.)
Lime. A rock powder consisting primarily of calcium carbonate that is used to raise the pH and decrease the acidity of acid soils.
Loam. An imprecise term, usually denoting a rich soil composed of clay, sand, and humus in desirable proportions. There are various types of loam such as sandy loam, etc.
Medium. The material in which plants are initially grown, such as perlite, pine bark, and peat moss.
Necrosis. A dead or dying area of plant tissue.
Nitrogen. A major plant nutrient especially important in the growth of foliage and stems.
Node. A slightly swollen spot on the stem of a plant where both leaf and axial buds develop.
NPK. An acronym for the three major plant nutrients contained in manure, compost, and fertilizers, and used to describe the amounts of each readily available. N is for nitrogen, P for phosphorus, and K for potassium.
Nutrient. Any substance, especially in the soil, which is essential for, and promotes the growth of plants. This comprises a group of a dozen or so elements, especially nitrogen, phosphorus, and potassium. (See NPK.)
Open Pollinated. Seed produced from natural, random pollination, so that the resulting plants are varied, as opposed to the uniformity seen in F1 hybrids.
Ovary. The part of a flower containing the ovules that will develop into seeds upon fertilization. With the style and stigma, it comprises the pistil, the female sexual organ of tomatoes.
Ovule. Within the ovary, the body which will contain the seeds upon fertilization.
Pathogen. Any organism that causes disease, usually applied to bacteria, viruses, and fungi.
Pedicel. A flower stem, as opposed to a leaf stem, or peduncle, from which the individual pedicels arise. (See peduncle.)
Peduncle. The main stem supporting a cluster of flowers, as opposed to the pedicels, which are the stems of individual flowers. (See pedicel.)
Petal. A specialized leaf that surrounds the reproductive parts of a flower. These are yellow on tomatoes. Petals are often colored to attract pollinating insects.
Phosphorus. A major plant nutrient especially important in the development of flowers.
Photosynthesis. The process by which the chloroplasts in plant cells use sunlight to convert carbon dioxide from the air with water vapor to form carbohydrates that are used as the basic food stuff for the growth of the plant.
Pistil. The female sexual organ of a flowering plant, comprising the stigma, style and ovary.
Pollen. The male sex cells which are held on the anther for transfer by insects, wind, or some other mechanism to the tip of the stigma, where they attempt fertilization of the female egg-cell, or ovule, in the ovary at the base of the style.
Pollination. The transfer of pollen from the male anther to the female stigma, enabling fruits to set and develop.
Potassium. A major plant nutrient that is especially important to the development of roots and stems.
Propagation. Increasing the stock of a plant by sowing seeds, taking cuttings, or dividing the plant.
Pruning. The removal of plant parts to improve the health, appearance, or productivity of a plant.
Pyrethrum. Botanical insecticide derived from the flowers of Chrysanthemum cineriifolium. Deadly to most insects but of low toxicity to mammals, and biodegrades quickly.
Respiration. The process by which plants convert the sugars created through photosynthesis back into energy to be used for growth and other metabolic processes of the plant.
Row cover. A cover (plastic, polypropylene, or spun bonded fiber) over one or several rows. In cooler climates, covers are often placed over direct seeded rows or recently transplanted crops to create a warmer, more humid microenvironment to facilitate rapid establishment of warm season crops. Can also provide crop protection from insects.
Seed. The fertilized ripe ovule which contains the embryo from which a new plant may develop given the proper conditions.
Sepal. In a flower, one of the outer, usually protective leaves that surrounds the petals. These are green in tomatoes and make up the outer layer of a blossom.
Sexual propagation. Production of new plants by seed, whereby the genetic material from two parent plants is combined, producing a new plant that is distinct, even if quite similar, to its parents.
Side dressing. To apply fertilizer to the soil surface around a growing plant.
Soil pH. A measure of the acid-alkaline balance of the soil. The scale runs from 1 to 14, with 7 being neutral. Soils with a pH below 7 become progressively more acid; and above 7 progressively more alkaline.
Species. The basic unit of plant classification. Plants within a species have several characteristics in common, but most importantly, can cross with one another, but not normally with members of another species. The classification of species is quite fluid, with periodic revision by botanists a fact of life that gardeners are forced to contend with.
Stamen. The male pollen producing part of a flower, consisting of the anther and its supporting structure.
Stem. The main trunk of the plant which has roots attached at its base and leaves, flowers, and fruit attached to the above ground portion.
Stomata. Tiny pores on the surface of plant leaves that can open and close to take in and give out water vapor (transpiration), oxygen, and carbon dioxide.
Stigma. The part of the female sex organ which receives pollen from the anther. Supported by the style, through which it is connected to the ovary. Often sticky when receptive.
Style. The part of the female sex organ that supports the stigma and connects it to the ovary.
Systemic. A pesticide that is absorbed by the plant either through the roots or leaves, and then moves through the plant to other plant parts, where it controls disease or insects.
Tap root. A thick central root attached directly to the crown of the plant that branches little if at all. (See also fibrous root.)
Transpiration. The passage of water through a plant from the roots by way of the plant's vascular system to the atmosphere via the leaves.
Transplant. A young plant past the seedling stage (noun); or replanting a small plant to a larger container or into the garden (verb).
Variety. A strain of plant having distinctive features which persist over successive generations in the absence of human intervention. Generally, variety applies to these naturally occurring strains, while cultivar applies to horticulturally developed strains.
Virus. A microscopic organism without a cell wall that is capable of causing disease in a tomato such as tomato mosaic virus.
Wilt. The loss of turgidity in plant tissue due to lack of water.
