SEED COLLECTION, SEED BANKING, GERMINATION, AND DORMANCY

Introduction

This glossary has been designed to strengthen your learning process developed with Terraformation through Terraformation Academy courses and textbooks and our Knowledge Base. This glossary will be continually updated as new training material is developed and delivered. Here you will find terminology related to seed collection, seed banking, seed germination, and other information that helps you ensure long-term seed quality and availability for your projects on the ground.

*If you are interested in diving into any anatomy/morphology-related terminology mentioned in this glossary, we recommend consulting the article “The Comparative Internal Morphology of Seeds“ (Martin, 1946) and the book A Systematic Treatment of Fruit Types (Spjut, 1994), where you can find the seed and fruit morphology of many taxa. For a general understanding in flower anatomy, please refer to Rudall (2007). For conifers, please consult the publication Anatomy & Morphology of Conifer Tree Seed (Kolotelo, 1997). 

**For terms related to seed dormancy and germination, you can consult the papers/books of Baskin & Baskin (2004), “A Classification System for Seed Dormancy”; Rosbakh, Baskin, & Baskin (2020), “Nikolaeva et al.’s Reference Book on Seed Dormancy and Germination Database”; Kildisheva et al. (2020), “Dormancy and Germination: Making Every Seed Count in Restoration”; and Baskin & Baskin (2014), Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination.

At the end of this glossary, you will also find a list of references used to develop this document, which you can explore if necessary.

A

Abnormal seedlings. In seed testing, seedlings which do not possess all the 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 (the abscission zone).

Accession. A distinct, uniquely identifiable sample of seeds representing a population, breeding line, or cultivar, which is maintained in storage for conservation and use.

Achene. One-seeded, dry, indehiscent fruit, formed from one carpel (see Flower*).

After-ripening**. The physiological maturation processes which occur in, e.g., seeds and fruits after harvest or abscission. After-ripening is often necessary for seeds to become germinable if fruits are immature. Also used for the specific seed-handling process itself.

Agar. Medium used for culture of bacteria and fungi under laboratory conditions. The medium is normally sterilized and supplied with necessary nutrients for growth of the culture in question.

Aging (of seed). Progression of cellular and biochemical events which ultimately leads to the death of the seed. Process of deterioration when a seed is exposed to extreme conditions of temperature and humidity. This process may harm the quality of the seed. See Deterioration of seed.

Ambient conditions. Normal surrounding temperature, humidity, and light without the use of artificial means of climate control.

Angiosperms. Botanical classification of the group of vascular flowering plants that produce seeds enclosed in an ovary, as different from gymnosperms. Among woody plants, the group includes bamboos, palms, and most species of forest trees. The term “hardwood” is sometimes used synonymously with angiospermous trees, although the wood is not always harder than that of gymnosperms (“softwood”). Compare Gymnosperms.

Anoxic or Anaerobic. Living in the absence of air or free oxygen.

Appendages. Tissues attached to fruits or seeds that aid in dispersal, like wings, hairs, spines, barbs, etc. Commonly found in dry fruits. These structures rarely hamper germination but can have a negative effect on storage, e.g., in cases where they tend to collect moisture, which can attract fungi, and thus indirectly influence storability. In any case, both wings and other appendices are redundant structures and are inconvenient in handling.

Aril. An additional integument or appendage formed on some seeds after fertilization. The aril is usually fleshy and nutritious and serves to attract dispersers.

B

Berry. Fleshy fruit developed from a single pistil (see Flower*) and with no hard layers. The fruit is usually many-seeded.

Binomial nomenclature. Biological system of naming the organisms in which the scientific species name is composed of two terms, where the first term indicates the genus and the second term indicates the specific epithet of the organism to which it belongs. See also Scientific name, Linnaean taxonomy.

Bruchid. Group of seed-infesting beetles mainly attacking seeds of the Fabaceae (Leguminosae) family.

C

Collection. A single event when fruits and/or seeds are collected from plants in the wild or in cultivation, usually defined by a place and time of collection. A seed collection in the field becomes a seed accession when accepted into a seed bank. In another perspective, a collection may refer to the sum of all the seed bank (or herbarium, museum, etc.) accessions collectively.

Combinational dormancy**. The seed or fruit coat is impermeable (preventing the uptake of water), and seed embryos are physiologically dormant. See also Dormancy, Physiological dormancy.

Cotyledons*. In seeds, the embryonic leaves, which in many families have absorbed the entire or the major part of the nucellus and endosperm, hence becoming the principal nutrient storage tissue. Monocotyledons have one, dicotyledons two, and conifers often have many cotyledons. During germination, the cotyledons may remain underground (hypogeal germination) or be pushed above the soil to become the first photosynthesising leaves (epigeal).

Cut test (of seeds). A “seed anatomy test” used to estimate germination and characterize a seed accession or collection through visual inspection. Seeds are dissected and classified into categories displaying similar characteristics. Cut tests are essential as a decision tool in seed processing and upgrading, but are useful in any situation where an estimate of germination is desirable.

D

Damage (of seed). Any injury to the seed. It may occur in various ways, such as mechanical (on seed-coat or embryos), heat (exposure to high harming temperatures), chemical (use of fungicides), or water (prolonged submersion in water) damage, and the severity may depend on the extraction/handling procedure and the seed type. For example, seeds with thin seed-coats are easily damaged by some processing methods. Potential damage to pure seed may occur from pathogens or pests.

Dehiscent fruit. Dry fruits that split open at maturity upon drying, usually while still attached to the tree, e.g., capsules, follicles, and some pods; the opposite of indehiscent fruit.

Desiccation sensitive seeds. Seeds which do not tolerate drying below a certain (high) critical moisture content. Often used equivalent to recalcitrant.

Desiccation tolerant seeds. Seeds that tolerate desiccation to a low moisture content of around 5%, including seeds with orthodox, intermediate–cool temperature sensitive, or intermediate–short lived storage behavior. Does not include seeds with recalcitrant or intermediate–partial desiccation tolerant storage behavior. See also Orthodox, Intermediate, Recalcitrant.

Deterioration (of seed). The cellular and biochemical events taking place within a seed and ultimately leading to the death of the seed. See Aging.

Diaspore. The dispersal unit of a seed. Some examples of fruits that are diaspores: a samara, nut, or drupe. Species with indehiscent fruits are usually diaspores because seeds are not released from fruits, while species with dehiscent fruits usually do not have diaspores because the seeds themselves are the unit of dispersal.

Diploid. A cell or organism with two basic chromosome sets, symbolized by 2n; the condition of vegetative tissues of most higher plants.

Disease. Physiological disorder caused by, e.g., infection by a pathogen, which causes abnormal, restricted, or delayed development or death of an organ or the whole plant.

Dispersal natural point. When the seeds have reached an optimum maturity stage and have developed a tolerance to desiccation. At this point, they can naturally detach from their mother tree. Seed dispersal is a good practical marker of seed maturity. However, in certain species, seed embryos are underdeveloped or not fully formed at seed dispersal. In these species, the embryo continues to grow after dispersal, and germination is prevented until the embryo reaches a species-specific critical length. Examples can be found in the Annonaceae, Apiaceae, Orchidaceae, Orobanchaceae, and Ranunculaceae families.

Dormancy (of seed)**. Physiological state in which a viable seed fails to germinate when provided with water and environmental conditions normally favorable to germination. Opposite of non-dormancy.

Drupe. Fleshy fruit consisting of an outer exocarp (fruit skin), a mesocarp (usually of fleshy or leathery substance), and an inner hard endocarp enclosing one or more seeds. The outer part is usually removed during processing, leaving the endocarp with enclosed seeds.

Dry after ripening**. Dormancy-breaking treatment where dry seeds are placed in warm, moderately humid conditions (e.g., 50%–60% relative humidity) for several weeks or months, mimicking a natural dry season.

Dry fruits. Fruits that contain little to no moisture at maturity. May open (dehisce) naturally to release seeds. These dehiscent fruits benefit from drying prior to cleaning, as the drying process will often open the fruits and allow the seeds to fall out. Some dry fruits, such as those of Astroloma, Eremophila, Persoonia, and Scaevola, do not open to release seeds. However, seeds can also be permanently encased in an indehiscent dry fruit (like many grass seeds) or endocarp (like a macadamia nut) that protects the seed within and acts as both the diaspore (dispersal unit) as well as the germination unit in many species.

E

Embryo*. The non-self-supporting immature organism formed from the zygote by cell division and differentiation; the rudimentary plant within the seed. Generative part of the seed that develops from the union of the egg and sperm cells and during germination becomes the young plant.

Embryo sac*. The mature female gametophyte of angiosperms. It is an oval, thin-walled structure found within the ovule of flowering plants, specifically within the nucellus. See also Nucellus and Ovule.

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*. The inner layer of the pericarp; e.g., the hard, bony part of drupe fruits like neem, teak, and Gmelina. See also Pericarp.

Endosperm*. The term is usually reserved for the triploid nutrient storage tissue surrounding the embryo in seeds of angiosperms (flowering plants). Sometimes also used for the haploid storage tissue of gymnosperms (cone-bearing seed plants), which is derived from tissue associated with the female gamete.

Epicotyl*. The apical end of the embryo which develops into the stem. In germinated seeds or seedlings, referring to the part of the stem between the cotyledons and the leaves.

Epigeal (or epigeous) germination**. The type of germination in which the cotyledons are forced above the ground by the elongation of the hypocotyl. Opposite of hypogeal germination.

Exocarp*. Outermost layer of pericarp; the skin on fleshy fruits as in Cornus, Malus, and Prunus. See also Pericarp.

F

Family. One of the eight major hierarchical taxonomic ranks in Linnaean taxonomy, classified above genus and below order.

Fertilization. The 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 where the seed cavity is filled with all tissues essential for germination. A filled seed is not necessarily alive; the opposite of empty seed.

Fleshy fruits. Fruits that at maturity contain a juicy, wet, sometimes fibrous pericarp surrounding the seed, typically dispersed by animals. Will generally become soft on maturity and are often colored. For fleshy, possibly recalcitrant seeds, collect the fruit in plastic bags, as it may lose viability quickly if allowed to desiccate. Prevent the rotting of fruits and seeds by periodically opening bags to allow for gas exchange.

Flower*. Angiosperm reproductive structure bearing carpels, pistils and/or stamens, and usually also sepals and/or petals. So-called flowers in gymnosperms are male and female strobili before and during pollination.

Fruit*. In a strict botanical sense, the mature pistil or pistils of the angiosperm flower, along with, in some types, associate structures like receptacle or perianth. In a less strict terminology, it includes the mature seed-bearing organs in gymnosperms, e.g., cones. Structure containing the seed.

Fume hood. Type of local ventilation device that is designed to protect personnel and the environment from toxic or volatile chemicals, using continuous airflow across the work surface to draw contamination away from the user.

Fungi. Diverse group of plant-infecting pathogens. Some fungi attack seeds directly, e.g., through cracks or damage to the seed-coat; others infect only the germinating seedling. Fungi multiply by spores, sometimes of different types. Spores are produced in vast numbers; they are tiny, long-lived, and usually dispersed by wind, which can carry them over long distances. Once the spores have been deposited on a suitable substrate, provided temperature and humidity are appropriate, the spores may germinate and form minute threadlike filaments, or hyphae, that penetrate into the plant tissue. Hyphae and their aggregate network, mycelium, make up the vegetative stage of the fungus. Whereas the fungal spores are relatively resistant to adverse environments (e.g., drought), the hyphae normally grow only under high moisture conditions and warm temperatures.

G

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 to form a zygote.

Genus. One of the eight major hierarchical taxonomic ranks in Linnaean taxonomy, classified above species and below family, marked by common characteristics or by one common characteristic.

Germination (of seed)**. The physiological processes in the first stages of growth of seed. Resumption of active growth in the embryo of a seed is 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 test**. Standard test carried out to determine the quality of a seed lot, i.e., the percentage of germinable seeds. The germination test is carried out under prescribed standard conditions under the optimal germination conditions of temperature, humidity, and light for the species in question. Dormant seed must be pre-treated in order to break dormancy before the germination test. See also Viability.

Gymnosperms. The botanical classification of the group of vascular seed plants in which the ovule (and later the egg) is not enclosed in an ovary (as different from angiosperms). Most gymnosperms produce seeds in cones (common name conifers). Non-cone-producing gymnosperms are Podocarpus, Ginkgo, and Taxus.

H

Haploid. A cell or an organism with one basic chromosome set, symbolized by n; the normal condition of gametes in plants, which are diploid in their vegetative tissues.

Herbarium. A facility that houses a collection of dried plant/voucher specimens, usually mounted and systematically arranged by reference, under conditions that preserve the specimens for uses such as research. See also Voucher specimen.

Hypocotyl*. The axial part of the embryo between the cotyledons and the radicle. In seedlings, the juvenile stem which is between the cotyledons and the root system.

Hypogeal (or hypogeous) germination**. Type of germination in which the cotyledons remain in the seed below the ground while the epicotyl elongates. Opposite of epigeal germination.

I

Imbibition**. The process of initial water uptake by seeds prior to germination.

Immature embryo**. Seed embryo which has not attained a development stage to make it capable of germination.

Impermeable**. A barrier restricting passage of motile molecules, e.g., a seed-coat obstructing water passage and hence imbibition.

Inbreeding. Production of offspring after self-pollination or after mating by closely related parents. 

Indehiscent fruits. Dry fruits (e.g., some pods, samaras, and nuts) that do not split open at maturity.

Inflorescence*. The assembly of several or many individual flowers into large clusters from a common axis, e.g., a panicle.

Insect. Any of a class (Insecta) of arthropods (such as bugs or bees) with a well-defined head, thorax, and abdomen, only three pairs of legs, and typically one or two pairs of wings. 

Integument. The one or two layers (often fused) of tissue covering and surrounding the nucellus of an ovule. When the ovule matures, the integument develops into the seed-coat.

Intermediate (seed storage behavior). Seeds with storage behavior that falls somewhere along a continuum between orthodox and recalcitrant, which may relate to having only partial tolerance to drying, cooling, and/or storage. Intermediate seeds are characterized by at least one of the following responses: 1. Partial desiccation tolerant: Drying to 50%–75% RH gives a longer shelf-life than storage at the lower moisture levels recommended for orthodox seeds; 2. Cool temperature sensitive: Seeds age faster when stored at conventional freezer temperatures compared to refrigerated temperatures; and 3. Short lived: Longevity of seeds increases with drying and cooling (as with orthodox seeds), but seeds still age rapidly during conventional storage and will die within about five years. See also Orthodox, Recalcitrant.

L

Linnaean Taxonomy. Particular form of biological classification (taxonomy) set up by Carl Linnaeus with eight major hierarchical taxonomic ranks. See also Binomial nomenclature.

Longevity (of seeds). The period of time seed will maintain viability in storage.

M

Mature. Of fruits: the stage of fruits when the seeds are ready to be dispersed, often visible by, e.g., color change, desiccation, and opening structures. A ripe fleshy fruit may appear round and full, soften or wrinkle, and change color, often falling to the ground and being fed upon by birds or mammals. A dry fruit may appear dry, brown, and woody, with some capsules dropped, dropping, or open. Of seeds: seeds which are fully germinable after extraction from their fruits and possible breakage of dormancy.

Maturity (of seed). Physiological status when seed vigor, desiccation tolerance, and longevity are expected to be highest. While it is difficult to monitor these traits in the field, changes in fruit color, seed color, or black layer formation (in some species) can be used as visual indicators to make preliminary assessments of optimal seed maturity. 

Mesocarp*. Middle layer of the pericarp; the pulp of berries and drupes. See also Pericarp.

Metabolism. The chemical changes within a cell that provide the energy required by a plant or animal.

Moisture Content. The amount of water present in a material, e.g., wood, soil, or seed. May be expressed in terms of weight of moisture as a percentage of the material’s oven-dry weight (“dry-weight basis”) or, preferably in the case of seeds and fruits, as a percentage of the material’s wet weight including water (“wet weight” or “fresh-weight basis”). Abbreviation: mc.

Morphological dormancy**. Seeds readily imbibe water; however, embryos are underdeveloped but differentiated and require time to grow before germination. See also Dormancy.

Morphophysiological dormancy**. Seeds readily imbibe water but have embryos that are underdeveloped and/or undifferentiated and physiologically dormant. See also Dormancy.

Mycelium. A mass of branching more or less loosely interwoven hyphae that make up the vegetative body of most true fungi. See also Fungi.

Mycorrhiza. [Myco = fungus; rhiza = root.] Fungi living symbiotically with plant roots. The fungus provides the plant with mineral nutrients and gets in return sugar and other organic compounds. 

N

Non-dormancy (of seed)**. Seeds imbibe water and germinate readily (within 4 weeks) over the widest range of environmental conditions possible for the species. Opposite of dormancy.

Nucellus. The body within a plant ovule in which the cavity known as the embryo sac develops. In seeds, the remains of the nucellus is a single, crushed layer of empty cells within the seed coat, surrounding the endosperm and embryo.

O

Orthodox (seed storage behavior). Term used to describe seeds which can be dried down to a low moisture content of around 5% and successfully stored at low or sub-freezing temperatures for long periods; the opposite of recalcitrant. See also Intermediate.

Ovary*. The part of the pistil that contains the ovule or ovules and ripens to form the fruit or pericarp. See also Flower*.

Ovule*. The egg cell plus associated cells which develop into the seed after fertilization. See also Flower*.

P

Peak germination**. A loose term which describes the point in time when the rate of germination is highest; it may be calculated in many ways.

Pest. Any organism causing damage to seeds by infection; e.g., mites, insects eggs, larvae, or adults mixed with seed and debris can cause the same damage as pathogens during storage and sowing. Pests are associated with predation by consuming part of the seed.

Pathogen. A disease-producing microorganism like bacteria, small fungi, or virus, but not, e.g., insects. Soil and organic matter always harbor potential pathogenic organisms. Pathogens may develop and cause diseases during ambient storage at relatively high humidity or during germination. Potential damage is thus dependent on storage and germination conditions. 

Pedicel*. The individual flower stalk in an inflorescence. See also Inflorescence.

Peduncle*. The main axis of an inflorescence or, in the case of single flowers, the flower or fruit stalk.

Pericarp*. Wall of a ripened ovary, i.e., fruit wall. The pericarp is homogeneous in some genera, and in others it is composed of three distinct layers: exocarp, mesocarp, and endocarp.

Phenology. Study of the relations between seasonal climatic changes (e.g., temperature, daylength, and precipitation) and periodic biological phenomena such as flowering, fruiting, leaf flushing, and dormancy.

Physical dormancy**. The seed or fruit coat is impermeable (preventing the uptake of water). Principal dormancy type in the Fabaceae/Leguminosae family. See also Dormancy.

Physiological dormancy**. Seeds imbibe water and possess fully developed embryos with a low growth potential, sometimes in combination with a mechanical constraint from the seed/fruit-covering layers. See also Dormancy.

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.

Predation (of seed or seedling). Consumption of a living organism by an animal predator, e.g., an insect eating a seed.

Pre-treatment**. Any kind of treatment applied to seeds to overcome dormancy and hasten germination, e.g., stratification or scarification.

Priming (of seed)**. Pre-treatment method to promote rapid and uniform germination. The seeds are soaked in a liquid solution (e.g., polyethylene glycol [PEG], sugar, or salt) of sufficiently low water potential to regulate moisture content at a level where the germination process initiates but radicle protrusion is prevented. Also referred to as osmotic priming.

Purity (of seed). Proportion of clean, intact seed (according to pure seed definition) of the designated species in a seed lot, usually expressed as a percentage by weight.

Q

Quality (of seed). A general term that may refer to the purity, germination capacity, vigor, and genotypic quality of a seed lot. 

Quiescent seed**. Inactive, resting. Applicable to non-dormant seeds during the interval between maturation on the parent tree and the onset of germination.

R

Radicle*. The embryonic root, i.e., the part of the seed embryo that develops into the primary root. In seeds, the radicle is always facing the micropyle.

Recalcitrant (seed storage behavior). Term used to describe seeds that cannot survive drying below a relatively high moisture content (30%–40%) and, for tropical species, do not tolerate low temperatures. The seeds rapidly lose their viability and cannot be successfully stored for long periods; the opposite of orthodox. See also Intermediate.

Relative humidity (RH). The amount of water vapor in the air compared to the maximum amount of water the air can contain when saturated. For example, 50% RH means that the air holds half of the total amount it could contain.

Respiration. Aerobic combustion of stored food reserves at physiological temperature by living organisms. Respiration is an essential part of the plants’ metabolism. Oxygen is consumed during the process and water and CO2 produced.

S

Samara. Dry, indehiscent, winged fruit with one or more seeds.

Sample (of seeds). In the context of seed testing, a small representative quantity drawn from a seed lot. 

Scarification (of seed)**. Disruption of hard seed-coats, usually by mechanical abrasion or brief chemical treatment in a strong acid, to increase their permeability to water and gasses, or to lower their mechanical resistance.

Scientific name. A name used by scientists to refer to an organism that consists of the genus and species. Scientific names usually come from Latin or Greek. These names are important because they allow people throughout the world to communicate unambiguously about plant species biology, ecology, physiology, genetics, functionality, etc. See also Binomial nomenclature, Linnaean taxonomy.

Seed*. In the strict botanical sense, the mature ovule which contains the embryo plus possible nutritive tissue, enclosed in protective layers of the testa or seed-coat (which originates from the integuments). In a broad sense, the term refers to the whole dispersal unit (see also Diaspore) — e.g., in indehiscent fruits, to the morphological seed (as defined above) plus the whole or part of the fruit that continues to enclose the seed during processing and handling, e.g., pyrene (stone), samara, or nut.

Seed bank. A facility important for scientific research and species conservation. Modern seed banks consist of climate-controlled rooms for seed banking activities following international guidelines. Critical steps of seed banking include seed cleaning, drying, storage, testing, and withdrawal.

Seed banking (or seed storage). A fundamental plant conservation practice used around the world to store seeds while maintaining viability and preserving the genetic diversity of seeds. It is the practice of cleaning, drying, storing, testing, and withdrawing seeds using standardized methods in seed banks for several years.

Seed-coat**. Protective outer layers on a seed derived from the integument of the ovule. When two layers of the seed-coat are distinguishable, the outer coat is called the testa and the inner the tegmen. When only one layer can be distinguished, it is called the testa.

Seedling. A young plant produced from a seed before it becomes a sapling, in contrast to plants produced by vegetative propagation. The latter are called cuttings, stumps, or plantlets depending on mode of propagation.

Seed lot. A specified quantity of seed of the same species, provenance, date of collection, and handling history, and which is identified by a single number of registration. An accession or portion of an accession.

Seed-transmitted pathogen. An infectious microorganism carried in, on, or with the seed with the potential of causing disease of the seedling or the plant, but harmless to the seed itself. 

Species. One of the eight major hierarchical taxonomic ranks in Linnaean taxonomy, classified immediately below the genus, comprising related organisms or populations potentially capable of interbreeding, and being designated by a binomial nomenclature. Species is the most basic unit of classification. However, for some (but not all) species there are taxonomic ranks below species, such as subspecies, variety, or form. See also Binomial nomenclature, Linnaean taxonomy.

Soil seed bank. Dormant, viable seeds of one or several species accumulated in the soil over one to several years that serve as a reservoir to recompose the natural vegetation.

Stone. Common term for the hard endocarp of a drupe containing the seed.

Stratification (of seed)**. Pretreatment of dormant seeds by storing them for a prolonged period in an imbibed stage at a certain temperature. Cold, moist stratification refers to the traditional pretreatment of temperate seeds by storing the imbibed seeds under cold conditions (originally in alternate layers with a moist medium). Under warm, moist stratification, the seeds are kept at a temperature of physiological activity.

Substrate. Here: the matter on which a germinating seed, seedling, and/or fungus grows.

Symbiosis. Literally “living together.” Applying to two organisms of different species forming an association with one another. If the symbiosis is of mutual benefit, it is called mutualism; if one of the symbionts benefits at the expense of the other, it is called parasitism.

Synonym (in taxonomy). Scientific name applied to a particular taxon in the past but which is not the currently accepted name according to the published scientific literature. There may be multiple synonyms for the same species.

T

Taxonomy. Hierarchical classification of organisms according to their presumed natural relationships. There are particular levels (ranks) in the taxonomic hierarchy. Levels for some organizations are domain, kingdom, division (or phylum), class, order, family, genus, species, subspecies, variety, and form. See also Linnaean taxonomy.

Testa*. The outer coat of a seed; usually hard or tough, but may be soft in some species (sarcotesta). See also seed-coat.

Triploid. A cell or organism with three basic chromosome sets, symbolized by 3n. Applicable to cells of the endosperm in seeds of angiosperms, which have three times the number of chromosomes in the reproductive cells.

V

Viability (of seed). Seeds which are capable of germination when given water and an appropriate environment (including breakage of possible dormancy) for reactivation of their biochemical processes are said to be viable. Viability tests are not necessarily the same as germination tests since viability may be measured indirectly on, e.g., a cutting test or TTZ staining. See also Dormancy and Vigor. 

Viable seed. A seed which can germinate under favorable conditions, provided that any dormancy that may be present is removed. 

Vigor (of seed). The seed properties which determine the potential for rapid emergence and development of normal seedlings under a wide range of field conditions. Seed vigor influences their storage potential. Less vigorous seeds deteriorate and reach the condition of total inviability more quickly compared to the ones of high vigor.

Vitrification. To make liquids solid without forming crystals; a “glassy state.” Forming ice crystals inside plant cells can be deadly.

Voucher specimen. A pressed plant sample (with branches and leaves in good condition and preferably with flowers and/or fruits) that helps document the identity of a species for future reference, supports collection name verification, and which is ideally deposited and safeguarded in a herbarium. Note that permission to collect a voucher specimen may be required prior to the collection. See also Herbarium.

W

Weight (of seed). Seed weight is indicated in the number of seeds per weight unit (usually kg) of the seed lot, including impurities. Another measure is the thousand seed weight, indicating the weight in grams of 1000 pure seeds. Seed weight of a subset of seeds from an accession can also be used to estimate the total number of seeds in an accession.

REFERENCE LIST

1. Air Science. Ductless Fume Hoods. https://www.airscience.com/application-category?cat=ductless-fume-hoods
2. Aboriginal Landcare Education Program (ALEP). (2012). Collect, treat and store seed. Learning guide. Greening Australia.
3. Carvalho, N. D., & Nakagawa, J. (1980). Sementes ciência, tecnologia e produção (p. 326p). Campinas: Fundação Cargill.
4. Chau, M. M., Angelova, D., Di Sacco, A., Wagner, J., Castillo-Díaz, & D., Meyer, V. (2020). The global seed bank index. Thousands of seed banks are needed to address seed supply shortages in ecosystem restoration. Terraformation Inc.
5. Invernón, V. R., de la Estrella González, M., Nieto, E. L., Seco, I. A., & Alcaraz, J. A. D. (2012). Manual de laboratorio de Botánica. El fruto. REDUCA (Biología), 5(2).
6. Kildisheva, O. A., Dixon, K. W., Silveira, F. A., Chapman, T., Di Sacco, A., Mondoni, A., ... Cross, A. T. (2020). Dormancy and germination: Making every seed count in restoration. Restoration Ecology, 28, S256–S265.
7. Kolotelo, D. (1997). Anatomy & morphology of conifer tree seed. Forest nursery technical series 1.1. British Columbia. Ministry of Forests. Nursery and Seed Operations Branch.
8. Martyn Yenson, A. J., Offord, C. A., Meagher, P. F., Auld, T., Bush, D., Coates, D. J., ... Broadhurst, L. (2021). Plant germplasm conservation in Australia: Strategies and guidelines for developing, managing and utilising ex situ collections. Australian Network for Plant Conservation.
9. Center for Plant Conservation. 2019. CPC Best Plant Conservation Practices to Support Species Survival in the Wild. Center for Plant Conservation, Escondido, CA.
10. Merriam-Webster Dictionary. (2002). “Insect.” https://www.merriam-webster.com/dictionary/insect
11. Rao, N. K., Hanson, J., Dulloo, M. E., Ghosh, K., Nowell, D., & Larinde M. (2006). Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International.
12. Schmidt, L. H. (2007). Tropical forest seed. Springer Science & Business Media.
13. Schmidt, L. (2000). Guide to handling of tropical and subtropical forest seed (pp. 263–303). Danida Forest Seed Centre.
14. Terraformation Academy (TFA). 2021. Foundations of seed banking (textbook).
15. Vozzo, J. A. (2002). Tropical tree seed manual (No. 721). US Department of Agriculture, Forest Service.