The glossary has been compiled, sometimes with modification, from the following sources:-
Terminology of Forest Science, Technology Practice and Products. Ed. F. C. Ford - Robertson. Soc. Am. For. Washington, D.C. 1971.
A Glossary of Genetics and Cytogenetics. By Reeger and others. Springer-Verlag, Berlin, Heidelberg, New York 1968.
Glossary of Botanical Terms commonly used in Range Research. Compiled by W. A. Dayton. USDA Misc. Publication No. 110, Washington D.C., revised 1950.
A Glossary of Botanic Terms. B. D. Jacobsen. 4th Edn. 1928. Duckworth, London.
A Dictionary of Scientific Terms. I. F. Henderson and W. D. Henderson. 4th Edn. by J. H. Kenneth 1949. Oliver and Boyd, Edinburgh.
Seeds. The Yearbook of Agriculture. USDA Washington D.C. 1961.
Seeds of Woody Plants in the United States. Agriculture Handbook No. 450. USDA Forest Service, Washington D.C. 1974.
The Methodology of Conservation of Forest Genetic Resources. L. R. Roche. FAO, Rome 1975.
Viability of Seeds. Ed. E. H. Roberts. Syracuse University Press 1972.
Glossary of Seed Germination Terms for Tree Seed Workers. F. T. Bonner. USDA Forest Service Gen. Tech. Rep. SO-49, Southern Forest Experiment Station 1984.
Glossary for forest tree improvement workers. E. B. Snyder, USDA, Forest Service 1972.
Eucalyptus seed. D. J. Boland et al. CSIRO, Australia 1980.
Oxford English Dictionary, 1933 edition.
Penguin Dictionary of Science. E.B. Uvarov, D.R. Chapman and A. Isaacs. 5th Edn. 1979. Penguin Books.
ABNORMAL SEEDLINGS:
In seed testing, seedlings which do not possess all normal structures required for growth, nor show the capacity for continued development.
ABSCISSION:
Natural separation of leaves, flowers and fruits from plants, generally associated with deterioration of a specialized layer of thin-walled cells.
ABSORPTION:
Penetration of one substance into the body of another, through interpenetration of particles among those already present.
ACHENE:
A one-seeded, dry, indehiscent fruit.
ADSORPTION:
The taking up of one substance at the surface of another; adhesion of unimolecular layer to surface of solid body.
AFTER-RIPENING:
Physiological processes which occur in seeds (or bulbs, tubers, and fruits) after harvest or abscission, which occur prior to and are often necessary for germination or resumption of growth under favourable external conditions.
ANGIOSPERMS:
The botanical name of the group of vascular flowering plants that produce seeds enclosed in an ovary. Includes the hardwoods, bamboos and palms.
ANTHESIS:
Stage of full flower expansion and bursting of anthers to release pollen.
ANTIPODAL NUCLEI:
Three of the eight nuclei that result from meiosis or sexual cell division in the female organ of seed-bearing plants.
APOCARPOUS:
Having separate or partially united carpels.
ARCHEGONIUM:
The female germ cell of gymnosperms, within which the ovum is contained.
ARIL:
An additional integument or appendage formed on some seeds after fertilization.
ASSIMILATION:
Conversion into protoplasm of ingested and digested nutrient material.
BERRY:
Pulpy indehiscent fruit developed from a single pistil and containing one or more seeds but no true stone.
BRACT:
1. Modified leaf subtending a flower on floral axis.
2. Modified leaf subtending a scale in female cones.
CAPSULE:
Dry, usually many-seeded fruit composed of two or more fused carpels that split at maturity to release their seeds as in Populus, Eucalyptus.
CARABINER:
A metal safety clip, used by climbers with ropes, which can be locked in the closed position as an insurance against accidental opening during climbing and fruit harvesting.
CARPEL:
Simple pistil or single member of a compound pistil.
CASE-HARDENING:
Of cones, the setting of their scales as a result of over-rapid superficial drying, so that they fail to open and discharge their seed.
CHAFF:
In eucalypts, sterile particles derived from infertile or non-fertilised ovules.
CHILLING:
See prechilling.
CHROMATID:
One of the paired microscopic, and usually rod-like, bodies which results from the longitudinal division of a chromosome at mitosis. Each chromatid develops into a chromosome in the daughter cell.
CHROMOSOME:
A microscopic, usually rod-like, body present in the cell nucleus and carrying the genes. The number, size and form of the chromosomes are usually constant for each species.
COTYLEDON:
Modified leaf or leaves of the embryo or seedling, which may contain the stored food reserves of the seed (= seed leaf). They are formed at the first node or at the upper end of the hypocotyl.
CUTINISATION:
The deposition of a waterproof, waxy substance (cutin) on or in the outer layers of cell walls at the surface of seeds, leaves and young stems.
DEHISCENT:
Splitting open at maturity to discharge contents, as a capsule discharging seeds.
DESORPTION:
Loss of moisture from a relatively moist hygroscopic material, such as seeds, to a relatively dry atmosphere until the two reach equilibrium.
DIPLOID:
A cell or organism with two basic chromosome sets, symbolized by 2 n; the condition for vegetative tissues of most higher plants.
DORMANCY:
A physiological state in which a seed predisposed to germinate does not, even in the presence of favourable environmental conditions.
DORMANCY, COMBINED:
Dormancy as a result of two primary factors, such as seedcoat dormancy and embryo dormancy.
DORMANCY, DEEP:
Dormancy which requires extensive afterripening to overcome; usually a double dormancy or a combined dormancy.
DORMANCY, DOUBLE:
Dormancy in both the radicle and the epicotyl of the embryo. To overcome it normally requires a warm treatment followed by prechilling or two periods of prechilling, interrupted by a warm treatment.
DORMANCY, EMBRYO:
Dormancy as a result of conditions within the embryo itself: inhibiting substances, incompletely developed embryo. Syn: internal dormancy.
DORMANCY, IMPOSED:
Dormancy as a result of some action, treatment, or injury to seeds in the course of collecting, handling, or sowing. Syn: secondary dormancy. Syn: Induced Dormancy, Secondary Dormancy.
| DORMANCY, INDUCED: | see: Dormancy, Imposed. |
| DORMANCY, INTERNAL: | see: Dormancy, Embryo |
DORMANCY, PHYSIOLOGICAL:
A type of Embryo Dormancy in which germination is prevented by a physiological inhibiting mechanism.
DORMANCY, SECONDARY: see: Dormancy, Imposed
DORMANCY, SEEDCOAT:
Dormancy as a result of seedcoat conditions: impermeability to gasses or moisture or mechanical restrictions.
DORMANCY, SHALLOW:
Dormancy which requires little or no afterripening to overcome.
DRUPE:
A stone-fruit such as a plum; the pericarp fleshy or leathery, containing a stone with one or more seeds.
EFFECTIVE KILOGRAM:
The weight of seed of any particular seed lot which can be expected to produce the same number of either viable seeds or plantable plants (according to local usage) as would be produced by one kilogram of standard seed.
EMBRYO:
The non-self-supporting immature organism formed from the zygote by cell division and differentiation; the rudimentary plant within the seed.
EMBRYO SAC:
The mature female gametophyte in higher plants.
EMPTY SEED:
A seed without any content, or without an embryo or embryo cavity if some residual tissue is present; the opposite of filled seed.
ENDOCARP:
Inner layer of the pericarp; e.g. the hard, bony part of the fruit of Prunus.
ENDOGENOUS:
Developed from a deep-seated layer of tissue. In a seed, developed from, or occurring in, the embryo.
ENDOSPERM:
Triploid nutrient storage tissue surrounding the embryo in seeds of angiosperms. The so-called “endosperm” of conifers is haploid, derived from tissue associated with the female gamete.
ENZYME:
A catalyst produced by living organisms and acting on one or more specific substrates; a ferment.
EPICOTYL:
Portion of the axis of a plant embryo or seedling stem between the cotyledons and the primary leaves.
EPIGEAL GERMINATION:
Germination in which the cotyledons are forced above the ground by the elongation of the hypocotyl.
EXOCARP:
Outermost layer of pericarp; the skin on fleshy fruits as in Cornus, Malus and Prunus.
EXOGENOUS:
Developed from a superficial layer of tissue. In seeds, developed from, or occurring in, the covering of the seed, either seedcoat or pericarp.
FEMALE GAMETOPHYTE:
Haploid nutrient storage tissue in seeds of gymnosperms; often mistakenly called the “endosperm” of seeds of gymnosperms.
FERMENTATION:
The process of chemical changes in organic substances caused by the catalytic action of a “ferment”, which may be an independent plant such as yeast or bacteria, or an enzyme. May be accompanied by the production of heat and of toxic substances, hence the fermentation of fleshy fruits may adversely affect the seeds which they contain.
FERTILIZATION:
Union of the nucleus and other cellular constituents of a male gamete (sperm) with those of a female gamete (egg) to form a zygote. In some species, fertilization may occur months after pollination.
FILLED SEED:
A seed with all tissues essential for germination. Syn: Full seed.
FLAIL:
An instrument for threshing cereals by hand, consisting of a wooden staff or handle, at the end of which a stouter and shorter pole or club is so hung as to swing freely.
FOLLICLE:
A dry dehiscent fruit formed from a single carpel, dehiscing along the ventral side only.
FREE RADICAL:
A group of atoms which usally exists in combination with other atoms, but which may exist independently for shorter or longer periods, e.g. the NH4 radical.
FUNICLE:
The slender stalk of an ovule or seed, attaching it to the ovary placenta.
GAMETE:
A male or female reproductive cell, typically the product of meiosis, capable of uniting, in the process of fertilization, with one of the opposite sex.
GAMETOPHYTE:
(=Prothallus). The part of the plant that produces gametes or sex cells.
GAUGE:
A term used in the UK and elsewhere to define thickness of thin films such as polyethylene. 100 gauge (UK) = 1 mil (USA) and approximately = 25 microns or 0.025 mm.
GENE:
The smallest transmissible unit of genetic material consistently associated with a single primary genetic effect. The genes are ultramicroscopic and act as if linearly arranged at fixed places (loci) on a chromosome.
GENOTYPE:
1) An individual's hereditary constitution, with or without phenotypic
expression of the one or more characters it underlies. The
genotype is determined chiefly from performance of progeny and
other relatives. It interacts with the environment to produce the
phenotype.
2) Individuals characterised by a certain genic constitution.
GERMINATION:
In general, resumption of active growth in the embryo of a seed as demonstrated by the protrusion of the radicle. In seed testing (ISTA definition), resumption of active growth in an embryo which results in its emergence from the seed and development of those structures essential to normal plant development.
GERMINATION CAPACITY:
Proportion of a seed sample that has germinated normally in a specified test period, usually expressed as a percentage. Syn: Germination percentage. It should be noted that in some earlier literature the term “Germination Capacity” has been used to express the total of the seeds which germinate plus the ungerminated but sound seeds (on cutting test), as a percentage of the seeds sown, but this meaning is excluded by the latest IUFRO definition (Bonner 1984 a). cf. Viability per cent.
GERMINATION ENERGY:
That proportion of germination which has occurred up to the time of peak germination, or the time of maximum germination rate, or up to some pre-selected point, usually 7 test days. (The critical time of measurement can be chosen by several means).
GERMINATION PERCENTAGE: see: Germination Capacity
GYMNOSPERMS:
The botanical name of the group of vascular flowering plants that produce seeds not enclosed in an ovary, the most important order of which is the Coniferales.
HAPLOID:
A cell or organism with one basic chromosome set, symbolized by n, the normal condition of gametes in plants which are diploid in their vegetative tissues.
HARD SEEDS:
Seeds which remain hard and ungerminated at the end of a prescribed test, because they have not absorbed water due to an impermeable seedcoat.
HAUSTORIA:
Suckers of parasite plants.
HILUM:
Scar on a seed marking the point of attachment to the ovary in angiosperms or to the megasporophyll of gymnosperms.
HUSK:
Outside envelope of a fruit, especially if coarse, harsh or rough as in the involucre of Carya.
HYPOCOTYL:
That part of the axis of a germinating embryo which is between the cotyledons and the radicle; in seedlings, the juvenile stem which is between the cotyledons and the root system.
HYPOGEAL GERMINATION:
Germination in which the cotyledons remain in the seed below the ground while the epicotyl elongates.
IMBIBITION:
The mechanism of initial water uptake by seeds; the taking up of fluid by a colloidal system.
IMMATURE EMBRYO:
Condition in which a morphologically immature embryo delays germination.
INDEHISCENT:
Refers to dry fruits that normally do not split open at maturity.
INTEGUMENT:
The tissue covering and surrounding the ovule. When the ovule matures, the integument develops into the seedcoat.
INVOLUCRE:
One or more whorls of bracts situated below and close to a flower or flower cluster; sometimes enclosing the carpels as in Tectona, Castanea and Fagus.
KARABINER: See under Carabiner.
KERNEL:
The nucellus of an ovule or of a seed, that is the whole body within the seedcoats.
KILOGRAM EFFECTIVE FACTOR (KEF):
The ratio of seedling recovery from standard seed to actual seedling recovery from a given seed lot.
LIPIDS:
A group of organic compounds that are esters of fatty acids and are characterized by being insoluble in water but soluble in many organic solvents. Simple lipids include fats and oils and act as one form of storage materials in plants and animals.
LOCULUS:
The cavity of an ovary or anther.
MACERATE:
To soften by steeping in a liquid, with or without heat; to wear away or separate the soft parts, by steeping.
MAST YEAR: see: Seed Year
MEIOSIS:
Specialized nuclear division prior to the formation of gamets. In a normal diploid organism meiosis reduces the number of chromosome sets from two (2 n) to one (n).
MESOCARP:
Middle layer of the pericarp; the pulp of berries and drupes.
METABOLISM:
The chemical changes within a cell that provide the energy required by a plant or animal.
MICROPYLE:
Minute opening in the integument of an ovule through which the pollen grain or pollen tube passes to reach the embryo sac; usually closed in the mature seed to form a superficial scar.
MIL:
One thousandth of an inch, approximately 25 microns or 0.025 mm. Used in USA to define thickness of thin films such as polyethylene. 1 mil is the equivalent of “100 gauge” (UK).
MITOSIS:
Division of a nucleus into two identical daughter nuclei by a process that separates the twin chromatids of each of the paired chromosomes, so maintaining the diploid condition.
MOISTURE' CONTENT:
The amount of water present in a material e.g. wood, soils or seeds. May be expressed in terms of weight of moisture as a % of the material's oven-dry weight (“dry-weight basis”) or, preferably in the case of seeds and fruits, as a % of the material's wet weight including water (“wet-weight” or “fresh-weight basis”).
MULTILOCULAR:
Many-celled, as an ovary.
NAKED STRATIFICATION:
Pre-chilling of seeds without the use of a moisture-holding medium.
NUCELLUS:
Tissue in the central part of the ovule and inside the integument, within which the embryo sac is embedded.
NUCLEUS:
A body of specialized protoplasm found in nearly all cells and containing the chromosomes.
NUT:
Dry, indehiscent, one-seeded fruit with a woody or leathery pericarp developing from an inferior compound ovary.
ORTHODOX:
Term used to describe species of which the seeds can be dried down to a low moisture content of around 5% and successfully stored at low or sub-freezing temperatures for long periods.
OVARY:
The part of the pistil that contains the ovule or ovules and ripens to form the fruit or pericarp.
OVULE:
The body within the ovary of the flower that becomes the seed after fertilization and development.
OVULIFEROUS:
Bearing ovules. Applied to the ovule-bearing scales in the cones of conifers (contrast bract scales).
PARTHENOCARPY:
The development either of seedless fruits or of fruits in which the seeds lack embryos. Results from a failure of pollination, a failure in fertilization, or a failure in embryo development.
PEAK GERMINATION:
A loose term which describes the point in time when rate of germination is highest; it may be derived in many ways.
PERICARP:
Wall of a ripened ovary that is homogeneous in some genera and in others is composed of three distinct layers: exocarp, mesocarp and endocarp.
PHENOLOGY:
(Study of) relations between seasonal climatic changes and periodic biological phenomena such as flowering and fruiting, leaf flushing and dormancy.
PHENOTYPE:
All characteristics of a plant, morphological, anatomical, and physiological, as determined by the interaction between genotype and environment.
PERIODICITY:
The tendency, in an individual, stand or species, to produce seed at more or less regular intervals of more than one year.
PERISPERM:
Nutritive tissue of a seed derived from the nucellus and deposited external to the embryo sac; diploid in contrast to endosperm which is triploid.
PHYSIOLOGICAL MATURITY:
A general term for the stage in the life cycle of a seed when development is complete and the biochemical components necessary for all physiological processes are active or ready to be activated.
PISTIL:
Ovule-bearing organ of an angiosperm, composed of ovary, style and stigma.
PLACENTA:
The organ which bears the ovules in an ovary, often the margin of the carpellary leaves.
PLANT PERCENT:
The %, by number, of seeds which develop into plantable plants (seedlings or transplants) at the end of a given period, generally the end of the nursery period at the time of field planting.
PLUMULE:
Primary bud of a plant embryo situated at the apex of the hypocotyl; portion of the seedling axis above the cotyledons, consisting of leaves and an epicotyl, which elongates to form the primary stem.
POD:
A superior, one-celled, one- or many-seeded dehiscent fruit of two valves. Resembles the follicle in being dehiscent and formed from a single carpel but differs from it in dehiscing on both sides.
POLYEMBRYONY:
Production of two or more embryos from a single ovule and in a single seed.
POME:
Many-seeded fruit of the apple family consisting of an enlarged fleshy receptacle surrounding the pericarp; pericarp papery and fleshy as in Malus and Pyrus or hard and stony as in Crataegus.
PRECHILLING:
Cold moist treatment applied to seeds prior to sowing in soil or germination in the laboratory, and designed to hasten afterripening or to overcome dormancy.
PRECURING:
The deliberate storage and slow air drying under shade of fruits and contained seeds in order to render them more suitable for subsequent operations, e.g. kiln drying, extraction and storage.
PURE SEED:
That component of a seed lot which consists of seeds of the designated species. According to ISTA rules, it includes not only mature, undamaged seeds but also undersized, shrivelled, immature and germinated seeds provided they can be positively identified as the designated species, and pieces of seed resulting from breakage which are more than half their original size. Excludes seeds of other species, wings of coniferous seeds, seeds of coniferous or leguminous species with seedcoats entirely removed, broken seed particles less than half the original size and other matter such as stones, twigs and leaves.
PURITY:
Proportion of clean, intact seed of the designated species in a seed lot, usually expressed as a percentage by weight.
QUIESCENT:
Inactive, resting. Applicable to non-dormant seeds during the interval between maturation on the parent tree and the onset of germination.
RADICLE:
Portion of the axis of an embryo from which the primary root develops.
RECALCITRANT:
Term used to decribe species of which the seeds cannot survive drying below a relatively high moisture content and cannot be successfully stored for long periods.
RECEPTACLE:
End of a flower stalk on which the floral organs are borne.
SAMARA:
Dry, indehiscent, winged fruit, one-seeded as in Fraxinus, Ulmus, or two-seeded as in Acer, Triplochiton.
SARCOTESTA:
Soft, fleshy outer layer of a testa.
SCARIFICATION:
Disruption of seed coats, usually by mechanical abrasion or by brief chemical treatment in a strong acid, to increase their permeability to water and gases, or to lower their mechanical resistance.
SEED:
A fertilized and mature ovule which contains an embryo and nutritive tissue and is enclosed in protective layers of tissue (seed coat).
SEEDCOAT:
Protective outer layers on a seed derived from the integuments of the ovule; when two coats are present, the thick tough outer coat is the testa and the thin inner coat is the tegmen.
SEED LOT:
A specified quantity of seed of reasonably uniform origin and quality.
SEED QUALITY:
A general term that may refer to the purity, germination capacity or vigour of a seed lot.
SEED YEAR:
In respect of any species, particularly trees of irregular or infrequent seed production, a year in which it produces, either as an individual or a crop, an adequate amount of seed. Many periodic seeders produce heavy (“bumper”) seed crops during their seed years.
SEEDLING RECOVERY:
The number of plantable plants obtained or expected at the end of the nursery period from one kilogram of seed.
SEROTINOUS:
Coming late, particularly applied to plant species or individuals that flower or fruit late in the season and to fruit or cones that remain on the tree without opening for one or more years (e.g. Pinus contorta).
SOUND SEED:
Equivalent to viable seed q.v.
SQUASH TEST:
A simple, indirect test of viability, by which seeds are first allowed to imbibe water and are then squashed with a pair of forceps to reveal the condition of the embryo. The number of seeds appearing fresh and healthy per unit weight of seed plus chaff (in eucalypts) or per 100 (in larger seeds) provides a rough estimate of viability.
STANDARD SEED:
For a given species, seed with “average” quality characteristics based on previous experience with that species. Used with particular reference to the seedling recovery figures to be expected from 1 kg of standard seed and its relationship to actual seedling recovery from a particular seed lot.
STIGMA:
The part of the pistil that receives the pollen.
STRATIFICATION:
Practice of burying seeds in moist medium, often in alternate layers to overcome dormancy; commonly applied to any technique which keeps seeds in a cold and moist environment.
STYLE:
The stalk of the pistil between stigma and ovary.
SUBMITTED SAMPLE:
The sample of seed submitted to a seed testing station.
SUBSTRATE:
Underlayer of soil, sand and other matter. The matter on which a fungus or germinating seedling grows.
SUTURE:
1. A junction or seam of union.
2. A line of opening or dehiscence.
SYNCARP:
A multiple or fleshy aggregate fruit, as the mulberry or Magnolia.
SYNCARPOUS:
Composed of two or more united carpels.
TEGMEN:
Inner seedcoat, usually thin and delicate.
TESTA:
The outer coat of a seed; usually hard or tough, but may be soft in some species (see sarcotesta).
THRESH:
To separate, by any mechanical means, e.g. rubbing, shaking, trampling, stamping, beating or intermittent pressure, the grains of any cereal from the husks and straw, especially by beating with a flail. Applied also to the separation of other than cereal seeds from their fruits.
TOLERANCE:
A permitted deviation (plus or minus) from a standard; in seed testing, the permitted difference between or among replicated measurements beyond which the measurements must be repeated.
TRIPLOID:
A cell or organism with three basic chromosome sets, symbolized by 3 n. Applicable to cells of the endosperm in seeds of Angiosperms, which have 3 × the number of chromosomes in the reproductive cells.
TUMBLING:
The operation by which cones or fruits are placed in a rotating drum, which rolls and tosses them around to induce the release of the contained seeds.
VIABILITY PER CENT:
At the end of a germination test, the total number of germinated seeds plus ungerminated but sound seeds (on cutting test), expressed as a percentage of the number of seeds sown.
VIABLE SEED:
A seed which can germinate under favourable conditions, provided that any dormancy that may be present is removed.
VIGOUR:
Those seed properties which determine the potential for rapid, uniform emergence and development of normal seedlings under a wide range of field conditions.
VIVIPAROUS:
Germinating while still attached to the parent plant.
WORKING SAMPLE:
A reduced seed sample taken from the submitted sample in the laboratory, on which some test of seed quality is made.
ZYGOTE:
The fertilized egg.
