Glossary
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Abaxial : the side or surface of an organ, eg a petal or organ system such as a branch, facing away from the axis that bears the organ or organ system.
Abscission : normal separation of flowers, fruit and leaves from plants.
Abscisic acid : plant hormone that regulates seed maturation; with water stress it closes stomata, promotes root growth and inhibits shoot growth; promotion of leaf senescence.
Acclimation : natural process of becoming inured to a climate.
Achene : is a small single-seeded dry fruit.
Adaxial : the side or surface of an organ, eg a petal or organ system such as a branch, facing towards the axis that bears the organ or organ system.
Adventitious : a plant organ that arises from an unexpected position, eg. sprouts that arise directly from roots, as in raspberry, or small plants that can arise from certain leaves.
Adventitious embryony : the production of an embryo/seed directly from somatic tissue of the ovule without fertilisation.
Aggregate fruit : a fruit formed by the coherence or connation of pistils that were distinct in the flower, eg blackberries.
Air layering, (marcottage) : multiplying a plant by inducing rooting on a root or shoot.
Alkaloids : a large family of nitrogen-containing metabolites in many vascular plants which defends against predators and includes toxins, medicinals, stimulants and sedatives.
Allele : copy of each gene on a chromosome; differences may lead to different traits.
Allelopathy : release by plants of substances into the soil that have negative effects on neighbours, thus decreasing competition for water and nutrients.
Alternate bearing : tendency of many fruiting species to produce large crops one year, but only meagre crops in the next year or years.
Androecious : plants that bear staminate (male) flowers only.
Androecium : collectively the stamens of one flower.
Androgynous : bisexual, with male and female flowers in the same inflorescence.
Androgynophore : a stalk bearing both stamens and pistil above the point of perianth attachment.
Andromonoecious : male and bisexual flowers on the same plant, but without female flowers.
Aneuploid : plant with a chromosome number not an exact multiple of the haploid number of related plants.
Anoxic : absence of oxygen.
Anther : pollen-bearing part of a stamen at the top of a filament.
Anthesis : the period when the flower opens, often used to refer to the bursting of the pollen sacs and pollen release.
Anthocyanins : pigmented water-soluble flavonoids responsible for most of the red, pink, purple and blue colours in plants.
Apical dominance : in most higher plants the growing apical buds inhibit the growth of lateral buds.
Apocarpous : a gynoecium with one or more carpels which are initially free from one another.
Apomixis : plant asexual reproduction through seed. Progeny of an apomictic plant are genetically identical to the maternal plant.
Arbuscules : branched structures of mycorrhizal fungi that form within penetrated cells; the sites of nutrient transfer between the fungus and the host plant.
Aril : a fleshy appendage of the seed, either on a seedcoat or arising from the base of the seed.
Asexual reproduction : Vegetative reproduction; reproduction without fertilization such as with tubers, bulbs or rooted stems, or from sexual parts such as unfertilised eggs or other cells in the ovule.
Autogamy : fertilization of a flower with its own pollen.
Autosomes : any chromosome that is not a sex chromosome.
Auxin : a compound with biological activities similar to but not necessarily identical to indole acetic acid. Induces cell elongation in stems, cell division in callus, lateral root formation at cut surfaces of stems, parthenocarpic fruit growth and ethylene formation.
Axil : the angle formed between any two adjoining organs, such as stem and leaf.
Backcross : a hybrid resulting from crossing an existing hybrid with one of its parents, thereby increasing the genes of that parent.
Bark : the collective term for all the tissues outside the cambium of a woody stem or root.
Berry : fleshy or pulpy indehiscent fruit with one or more seeds embedded in the fleshy tissue of the pericarp.
Biennial bearing : cropping every other year.
Biotic : referring to what is living.
Bisexual : having both male and female present and functional in the same flower or inflorescence, hermaphrodite.
Bletted : some very astringent fruits are best if bletted. Fruits are left to ripen till they are very soft, when full sweetness and flavour develops.
Bloom : fragile powdery surface layer, eg the waxy bloom of plums and grapes.
Brackish : somewhat salty.
Bract : a modified, reduced leaf or leaflike part just below and protecting an inflorescence or stalk, often small.
Breba : first or spring crop of edible figs.
Brix : the angle of light transfer through a fruit pulp solution is positively correlated with increasing concentration of dissolved substances, mainly sugars. This change in angle can be measured by a refractometer and quoted as degree Brix. Levels below 8 are low in sugar and greater than 18 is very sweet.
Brochidodromous : leaf venation in which the secondary veins do not terminate at the margins but are joined in a series of prominent arches.
Bud : an immature or embryonic shoot, flower or inflorescence, frequently enclosed in scales.
Bud ring : several closely spaced buds without subtending leaves.
Bud sport : mutant arising from a bud.
Budding : Grafting by inserting a bud into a slit or hole made in the bark of a stock plant.
C3 plants : plants in which the first stable product of photosynthetic carbon dioxide fixation is a 3-carbon compound.
C4 plants : plants in which the first stable product of carbon dioxide fixation is a four-carbon compound.
Caducous : parts of a plant that are shed or drop off early in development.
Calcareous : soils containing calcium carbonate.
Callus : a small hard protrusion of undifferentiated (parenchyma) tissue formed at a wounded surface.
Calyx : collective term for the outer separate or united sepals of a flower; the outer series of flower parts.
CAM plants : plants that fix carbon dioxide during the night into a 4-carbon compound.
Cambium : the growing or dividing single layer of cells located between the wood and bark.
Cane : stem of vines and brambles in the dormant stage.
Capsule : in angiosperms, usually a dry fruit formed from two or more united carpels and dehiscing at maturity to release the seeds.
Carpel : simple pistil or unit of a combined pistil.
Carpellody : stamens develop abnormally into carpel-like fleshy structures.
Cation exchange capacity : a measure of the soil's ability to hold such elements as K, Ca, Mg, Na against leaching. High CEC denotes fertile soil.
Catkin : a scaly spike of usually unisexual and reduced flowers.
Cauliflorous : having flowers on the stem or large branches.
Central leader : main dominant stem of a plant.
Chance seedlings : seedlings where parentage is unknown, random or uncontrolled and subject to the variations of sexual reproduction. A number of important fruit varieties have resulted from selection of promising chance seedlings.
Chartaceous : papery in texture.
Chilling requirement : The growth of flower or vegetative buds in spring, eg with deciduous plants, requires that a certain quantum of cold be experienced. This is often measured in hours experienced by the plant below 7°C.
Chlorophyll : a group of light-absorbing pigments active in photosynthesis.
Chloroplast : the organelle that is the site of photosynthesis in plants (eukaryotic organisms).
Chlorosis : the yellowing of plant leaves characteristic of nutrient deficiency.
Cladode : a stem that functions as a leaf, eg. some cacti.
Cleistogamy : self-pollination prior to flower opening eg hermaphrodite papaya.
Climacteric : marked rise in respiration at the onset of ripening that occurs in all fruits that ripen in response to ethylene.
Clone : group of plants vegetatively propagated from a single mother plant or a mutant.
Compitum : a tract of transmission tissue in the gynoecium that is common to all the carpels of one flower and that allows pollen landing on any one stigma or part of a stigma to fertilise ovules in any carpel.
Complete flower : having all the components: pistils, stamens, petals and sepals.
Cone : mass of ovule-bearing or pollen-bearing bracts or scales arranged spirally on a cylindrical or globose axis.
Connate : one organ is fused to another organ (or organs) of the same kind.
Coppicing : severe pruning of trees down to the stump and then allowing them to regrow. Not all trees can be coppiced.
Coriaceous : leathery in texture.
Corolla : the second floral whorl of a complete flower, collective term for all free or united petals of a flower.
Corymb : flat-topped inflorescence with outer pedicels longer than inner and flowers opening centripetally; pedicels may be simple or compound.
Cotyledon : the first, rudimentary embryonic leaf of seed plants.
Cross-pollination : pollination by a genetically different plant. An outcross is a cross to an unrelated individual.
Crotch angle : subtending angle between branches or stem.
Cryptocotylar : of germination, when the cotyledon/s is/are not exposed and photosynthetic.
Cryptogeal germination : the seedling germinating in such a way - usually by elongation of part of the cotyledon - that the plumule is carried below the surface of the soil.
Cultivar : a cultivated variety, usually given a unique name. Eg. Mangifera indica cv R2E2.
Cuneate : wedge-shaped; triangular and tapering to a point at the base.
Cuticle : waxy covering on the surface of stems and leaves that acts to prevent desiccation in terrestrial plants.
Cutting : a detached portion of stem or other plant part which, when rooted, produces a whole plant.
Cyme : an irregular umbellate inflorescence in which the primary axis bears a single terminal flower which develops first.
Cytokinins : compounds with many developmental effects on plants, including leaf senescence, nutrient mobilization, apical dominance, formation and activity of shoot apical meristems, floral development, breaking of bud dormancy and seed germination.
Deciduous : detaching or falling off, usually referring to leaves, leaf tips or sepals and petals of flowers after expansion.
Decussate : arranged along the stem in pairs, each pair at right angles to the pair immediately above or below, as in leaves.
Dehiscence : splitting or opening in a regular manner allowing pollen or spores to escape.
Dehiscent dry fruit : mature fruit that has a dry pericarp that opens to let seeds escape.
Denitrification : Process by which soil anaerobic microbes convert nitrate or nitrite to the gases nitrous oxide or nitrogen, subsequently lost to the atmosphere.
Dentate : toothed, having triangular teeth perpendicular to the margin (leaf description).
Determinate : the apical meristem ceasing extension growth, eg with a flower terminating axial growth
Dichogamy : Male and female organs mature on the same plant at different times, promoting natural cross-pollination.
Dicotyledon : one of the 2 classes of flowering plants characterised by 2 seed leaves (cotyledons) in the embryo.
Dioecious : species with staminate and pistillate flowers on separate individuals, unisexual.
Diploid : plant cell with two basic haploid sets of chromosomes in the nucleus.
Distichous : leaves or other lateral organs arranged in two alternating rows on opposite sides of a stem and thus in the same plane.
Dominant : refers to inherited traits; with dominant alleles one copy is sufficient to produce the trait.
Dormant : not active, awaiting stimulus to fulfil a function.
Drupe : a fleshy indehiscent fruit having a hard endocarp and a single seed, sometimes having more than one encased seed.
Drupelet : a diminutive drupe, eg raspberry fruit.
Druse : a crystalline form of calcium oxalate that is common in plant cells.
Ectomycorrhiza : mutualistic association between fungi and roots in which fungal hyphae invest the roots forming a mantle and weave between the outer cells.
Edaphic : the physical, chemical, and biological properties of soil that influence the life of organisms.
Emasculate : removal of immature staminate flower structures (anthers) to prevent self-pollination.
Embryo : the rudimentary plant in a seed formed after sexual or asexual reproduction.
Endocarp : inner layer of a pericarp.
Endosperm : in angiosperms, an embryonic nutritive tissue formed during double fertilization of a sperm with the polar nuclei, making it triploid.
Eophyll(s) : the first fully-expanded leaf (or leaves) produced by a seedling.
Epicarp : outer layer of the pericarp or matured ovary.
Epicotyl : portion of the embryo or seedling above the cotyledons.
Epidermis : Outer layer of cells.
Epigeal germination : emergence of cotyledons above the soil.
Epigenetic : heritable changes of gene expression without modification of the DNA sequence.
Epigynous : flowers with the floral parts attached above the level of insertion of the ovary, arising from tissue that is fused to the ovary wall.
Epiphyte : a plant that uses another plant for support but does not take nutrients from it.
Ethylene : A gas that functions as a plant hormone. Important effects on plant growth and development including stimulating or inhibiting elongation of stems and roots, enhances fruit development, suppresses flowering on most species, increases abscission of flowers and fruit.
Etiolation : elongation, discolouration and poor plant growth due to lack of chlorophyll.
Eucamptodromous : leaf venation in which the secondary veins do not terminate at the margins but which gradually diminish inside the margin.
Eukaryote : having a true nucleus.
Evergreen : a plant with live leaves persisting through one or more winter seasons.
Exocarp : outermost layer of the fruit wall (pericarp).
Fascicle : a cluster of flowers arising from the same point without a peduncle.
Fertigation : application of fertilizers, soil amendments or other water soluble products through an irrigation system.
Fibrous roots : usually formed near the surface, these roots have a large surface area to absorb moisture and nutrients.
Field capacity : water content of a soil after being saturated with water and the excess has been allowed to drain away.
Filament : stalk like portion of a stamen, supporting the anther.
Flavonoids : a large group of plant polyphenolic compounds, including anthocyanins, flavones, flavanols and isoflavones.
Foliar fertilization : nutrients dissolved in water and applied to the foliage of the plant thru which they are absorbed.
Follicle : a dry, dehiscent fruit formed from one carpel and dehiscing along the line of fusion of its edges.
Fruit set : the beginning of fruit growth on the plant; this may occur following pollination and fertilization, or pollination without fertilization, or without either.
Gall : large swelling on plant tissues caused by bacteria, fungi, nematodes or insect parasites.
Gamete : reproductive cell. A cell or nucleus that fuses with another in sexual reproduction to produce a zygote.
Geitonogamy : pollination by one flower of a different flower on the same individual.
Gibberellins : a large group of chemically-related plant hormones associated with promotion of stem growth, seed germination and many other functions.
Girdling : (cincturing, ringing) removal of a ring of bark from a woody stem that interrupts transport in the phloem until regrowth takes place.
Glabrous : Having no hairs, bristles or stalked glands.
Glaucous : surface with a fine white substance (bloom) that will rub off.
Globose : globe-shaped, spherical.
Guard cells : the pair of specialised epidermal cells surrounding the stoma pore regulating its opening and closing.
Guttation : the process by which water passes from inside the leaf and is deposited on the outer surface, often on the edge or from points.
Gymnosperm : seed-bearing plant with the ovules borne on the margins or surface of a sporophyll and not enclosed by fusion of the sporophyllar tissue.
Gynoecious : plants that bear pistillate (female) flowers only.
Gynoecium : whorl or group of carpels in the centre or at the top of the flower; all the carpels in a flower.
Gynomonoecious : plants that bear both pistillate and perfect (hermaphrodite) flowers.
Halophyte : plant with the capability to grow in saline habitats.
Haploid : plant cell having a single set of chromosomes in the nucleus.
Herkogamy : where pollen presentation and receipt is spatially separated within an individual flower, or between individual plants.
Hermaphrodite : a flower with functional stamens and carpels.
Hesperidium : a berry where the endocarp is a mass of succulent juice sacs.
Heterostyly : a flower in which styles and stamens are of different heights/lengths relative to each other to promote cross pollination.
Heterozygous : non-identical alleles on a chromosome.
Hilum : a mark or scar on a seed produced by separation from the funicle or placenta.
Histerant : where flowering takes place prior to leaf emergence after winter in deciduous species.
Homozygous : identical alleles on a chromosome.
Hypanthium : floral tube formed by the fusion of the basal portions of the sepals, petals and stamens from which the rest of the floral parts emanate.
Hypocotyl : the portion of the axis of the plant embryo below the point of attachment of the cotyledons; forms the base of the shoot and the root.
Hypogeal germination : emergence of cotyledons below the soil surface.
Imbibition : initial taking up of water, particularly with seeds, prior to germination.
Imbricate : applied to leaves or to the parts of the flower when they overlap each other in a regular arrangement.
Imparipinnate : a compound leaf with a terminal pinna.
Imperfect flower : a unisexual flower; lacking either male or female parts.
Inarching : a form of grafting whereby two plants are grown side by side, one to be the stock and the other to be the scion. They are both prepared for grafting and bound together and allowed to heal before the top of the rootstock and the bottom of the scion are severed.
Incomplete flower : flower lacking at least one of the four basic parts : sepals, petals, stamens or pistils.
Indehiscent : not opening naturally when ripe.
Indeterminate : the apical meristem produces an unrestricted number of lateral organs, in particular, when the axis is not terminated by a flower.
Inferior ovary : one with the flower parts growing from above; one that is adnate to the calyx. Fruits from these have an apical calyx.
Inflorescence : any complete flower cluster including branches and bracts; clusters separated by leaves are separate inflorescences.
Integrated pest management : pest management using a combination of methods - genetic, biological, management and chemical.
Integument : natural covering, such as skin, shell or rind; also spelled as tegument.
Involucre : a group of inflorescence bracts surrounding an inflorescence.
Jasmonic acid : plant signalling molecule found in membrane lipids which regulates plant growth and activates plant defences against insects and fungal pathogens.
Juvenile : plant, organ or tissue that is not yet fully developed or mature; a plant that is unable to produce flowers and fruit. Morphological features may differ between juvenile and mature plants.
Kernel : Mature embryo; the seed.
Lamina : blade or expanded portion of a leaf.
Lanceolate : lance-shaped, longer than wide, widest below the middle, tapering toward the apex, or both apex and base: resembling a lance head.
Lateral roots : Arise from the pericycle in mature regions of the root through the establishment of secondary meristems that grow out throughthe cortex and epidermis, establishing a new growth axis.
Latex : complex, often milky solution exuded from cut surfaces of some plants, representing the cytoplasm of laticifers and may contain defensive substances.
Laticifers : In many plants, elongated phloem cells that contain rubber, latex and other metabolites.
Layering : partial burial of stem tips or lightly injured sections of stem to encourage rooting. Once rooted, these sections can be removed to form new plants.
Leaflet : single segment (blade) of a compound leaf.
Legume : member of the family Fabaceae often associated with rhizobia (nitrogen fixing bacteria).
Lenticel : a corky spot on the surface of a twig or fruit; sometimes persists on the bark or skin to admit air into the interior.
Light soils : with a high percentage of sand, are free-draining and easily cultivated.
Lignin : polymer that may be associated with celluloses and proteins. When deposited in secondary walls, it adds strength and has significant defensive properties.
Limen : rim at the base of an androgynophore.
Littoral : shoreline environment.
Locule : a compartment or cavity of an ovary, anther or fruit.
Meiosis : the two-stage division of a diploid nucleus during which gene recombination occurs and the number of chromosomes is halved.
Meristem : region of a plant where undifferentiated cells divide, generating new cells that ultimately differentiate.
Merous : the number of parts per whorl in a flower that characterises a particular species.
Mesocarp : fleshy part of the wall of a succulent fruit; the middle layer of the pericarp in a drupe.
Mesophyll : leaf tissue found between the upper and lower epidermal layers.
Micronutrient : a nutrient required in small amounts by plants.
Mineralisation : the process of breaking down organic compounds by soil microbes that releases nutrients in a form that can be assimilated by plants.
Mitosis : the normal division of a nucleus, whether haploid or diploid, during which chromosomes are replicated.
Monoecious : having stamens and pistils in separate flowers on the same plant.
Monotypic : having only one representative.
Mother cells : special cells in the anther and ovule that give rise to pollen or egg cells.
Mycelium : the mass of hyphae that forms the body of a fungus.
Mycorrhiza : a mutualistic association between a fungus and a plant, occurring primarily in the roots.
Naked flower : having no perianth.
Necrosis : a type of cell death.
Nectar : the sugary fluid produced in specialised glands of some flowers to attract insects as pollinators.
Nectary : a gland that secretes nectar.
Node : the narrow region on a stem where a leaf or leaves are or were attached.
Nodules : specialised organs of a plant host containing symbiotic nitrogen fixing microbes.
Nucellar embryony : pollination occurs but there is no exchange of genetic material. Instead the embryo is formed from tissue surrounding the ovule and the progeny produced are clones of the parent.
Nucellus : maternal tissue surrounding the ovule.
Nut : a dry, hard, indehiscent, one-celled and one-seeded fruit; usually derived from a unilocular ovary.
Nutation : spontaneous spiralling movement of a growing plant part, especially with vines, caused by variation in the growth rates on different sides.
Oblate : a globose shape but flattened at the poles eg apple.
Obovate : egg-shaped with the broadest part near the apex.
Operculum : a deciduous cap on a flower bud.
Orthotropic : the stem growing more or less erect.
Osmophore : Tissue or a gland, usually associated with flowers, from which aromas emanate.
Ovate : egg-shaped, about 1.5 times as long as broad, with the wider part at the basal end.
Ovule : In seed plants, the structure that contains the embryo sac and develops into the seed after fertilization of the egg contained within it.
Panicle : A compound raceme; an inflorescence in which the lateral branches arising from the peduncle produce flower-bearing branches instead of single flowers.
Palmate : radiately arranged, ribbed or lobed, as in the fingers of a hand.
Paripinnate : having a pair of leaflets at the apex.
Parthenocarpy : production of fruit without viable seeds, as in bananas and some grapes; may be induced artificially.
Pedicel : the secondary stalks of a compound inflorescence bearing individual flowers.
Peduncle : main flower stalk of a compound inflorescence, supporting either a cluster of flowers or the only flower of a single-flowered inflorescence.
Peltate : having the stalk of a leaf attached to the lower surface of the blade somewhere within the margin rather than on the margin.
Perennial : a plant that lives for more than 2 years.
Perfect flowers : having both functional stamens and pistils.
Perianth : calyx and corolla collectively, or the calyx alone if the corolla is absent.
Pericarp : the walls of a ripe ovule or fruit; its layers may be fused into one, or separated or divisible into epicarp, mesocarp and endocarp.
Petiole : leaf stalk, sometimes absent.
Phanerocotylar : of germination, when the cotyledon/s is/are exposed and photosynthetic.
Phloem : tissue that transports products of photosynthesis and other metabolites from mature leaves to areas of growth and storage, including the roots.
Pilose : covered with air, especially soft hair.
Pinnate : compound leaf, having lobes or blades of a leaf arranged along the sides of a common axis; also applies to major lateral veins.
Pistil : the female organ of a flower, collectively ovary, style and stigma (gynoecium) consisting of of one or more carpels.
Pit : The hard endocarp that encloses the seed of a drupe.
Placenta : ovule-bearing part of the ovary and seed-bearing surface in the fruit.
Plagiotropic : the stem or branches being held more or less horizontal.
Plicate : when a leaf lamina is folded like a fan.
Plumule : the young shoot above the cotyledon(s) of an embryo or seedling.
Pod : any dry dehiscent fruit.
Pollarded : cut back to the trunk to produce a dense mass of branches on regrowth.
Pollen : male spore-like structures produced by anthers in flowers and by male cones.
Pollen tube : microscopic tube that grows down the stigma from the pollen grain; through it the sperm cells are deposited into the embryo sac.
Pollination : the process by which pollen is transferred from the anther where it is produced, to the stigma of a flower.
Polyad : pollen aggregated into units of many grains each.
Polyembryony : a condition in which two or more embryos are formed in a single ovule.
Polygamous : a tree with hermaphrodite, pistillate and staminate flowers.
Polyploidy : having more than twice the haploid number of chromosomes per nucleus.
Pome : fruit in which the floral cup forms a thick outer fleshy layer and has a papery inner pericarp layer (endocarp) forming a multi-seeded core, eg apple, pear, quince.
Pomology : the branch of science dealing with fruit and fruit culture.
Precocious : developing early, often used with fruit or when flowers appear before leaves.
Protandry : the termination of the shedding of pollen of a plant or flower prior to receptivity on the same plant or flower.
Protogyny : the termination of stigma receptivity prior to the maturation of pollen on the same plant or flower.
Pseudocarp : fruit that develops not only from the ripened ovary, or ovaries, but from non-ovarian tissues as well.
Pubescent : covered with fine, short, soft hairs.
Pyriform : pear-shaped.
Pyrene : hard or stony endocarp; nutlet.
Raceme : an inflorescence in which the single flowers are borne on pedicels arranged singly along the sides of a flower-shoot axis.
Rachis : main axis of a spike or of a pinnately compound leaf, excluding the petiole.
Radicle : portion of the embryo below the cotyledons that will form the roots.
Ramiflorous : flowering on the branches, but below the leaves.
Recalcitrant seeds : these are rich in free water and do not tolerate nor survive desiccation.
Receptacle : portion of the axis of a flower stalk on which the flower is borne.
Recessive : refers to inherited traits; with recessive alleles two copies are required to produce the trait.
Regular flower : all flower parts radially symmetrical of similar size and shape.
Rhizome : a slender to much swollen underground stem that grows more or less horizontally.
Rhizosphere : the immediate microenvironment surrounding the root.
Riparian : of river banks or lake shores.
Root cap : cells at the root apex that cover and protect the meristematic cells from mechanical injury as the root moves thru the soil.
Root hairs : microscopic extensions of root epidermal cells that greatly increase the surface area of the root, providing greater capacity for absorption of soil ions and water.
Rooting hormone : plant hormones prepared usually as a fine powder or liquid in which the ends of cuttings can be dipped to enhance rooting.
Rootstock : the portion of a grafted or budded plant that provides the root system; may include a length of stem.
Russetting : (of fruit skin) reddish-brown discolouration.
Salinity : high concentrations of total salts in soil.
Sap : fluid content of the xylem, sieve elements of the phloem and the cell vacuole.
Saprophyte : a plant that feeds on dead organic matter.
Sarcotesta : fleshy testa.
Scale : reduced leaves that are usually sessile and seldom green; sometimes epidermal outgrowths if disc-like or flattened.
Scabrous : sandpapery.
Scarification : scratching of seed coverings to allow gas exchange and water uptake to enhance germination.
Sclerophyll : hard-leaved.
Scurfy : clothed in bran-like scales, eg. fruit of sapodilla.
Seed coat : the outer protective layer of a seed that develops from the integument of the ovule, testa.
Senescence : an active developmental process in which cellular structures and macromolecules are broken down and translocated away from the senescing organ (typically leaves) to actively growing regions that serve as storage sinks.
Sepal : one of the parts of a calyx or outer set of flower parts; may be separate or united to another sepal.
Scion : part of a plant which will be budded or grafted onto a rootstock.
Serrate : having sharp saw-like teeth pinted towards the apex.
Sessile : without a stalk.
Sieve elements : phloem cells that conduct sugars and other organic materials from their sites of synthesis to other areas throughout the plant.
Simple fruit : one that ripens from a single ovary.
Spadix : spike with a thickened fleshy axis eg coconut palm.
Spathe : large bract at the base of a spadix, enclosing it (at least initially) as a sheath.
Spike : type of inflorescence having sessile flowers on a long common axis.
Sporangium : a structure within which spores are formed, plural sporangia.
Sporophyll : a more or less leaf-like organ on which one or more sporangia are borne.
Sport : an unusual vegetative form resulting from a mutation or somatic segregation; may be part or all of a plant.
Spur : short stubby lateral branches that grow from the branches of several fruiting species and produce fruits for 2-4 years, eg apples and peaches.
Stamen : sporophyll within the flower; in angiosperms, the floral organ that bears pollen.
Staminate : having pollen-bearing stamens only, on flowers or inflorescences or individual plants of a dioecious species; male.
Staminode : an aborted or rudimentary stamen in which the anther does not develop and remains sterile.
Stem cells : uncommitted slowly dividing initial cells that produce all the cells in the meristem and thus all the cells in the entire plant.
Stenospermocarpy : the production of aborted or incompletely developed seeds following fertilization, with subsequent normal fruit development., eg some varieties of seedless grapes.
Stigma : pollen-receptive part of a pistil, often enlarged and sticky, usually at the tip of the style.
Stipule : one of a pair of lateral appendages at the base of a leaf petiole.
Stolon : prostrate or trailing more or less above-ground stem which produces roots and sometimes erect shoots at its nodes.
Stoma : microscopic pore in leaf epidermis surrounded by a pair of guard cells. They regulate the gas exchange (water, oxygen and carbon dioxide) of leaves by controlling the dimension of the stomatal pore; mostly on the under side in dicots and conifers but both with monocots.
Stone : drupe.
Stratification : moist, cold storage.
Style : the narrow upper part of ovary that supports the stigma.
Suberin : a complex of fatty substances present in the wall of cork tissue that waterproofs it and renders it more resistant to decay.
Suckers : many stems arising from the base of a tree or shrub and gradually spreading the diameter of the basal area.
Superior ovary : an ovary with the flower parts growing from below it.
Surfactant : a detergent, adjuvant or other surface-active agent that enhances penetration and action of applied chemicals.
Suture : pre-detemined line along which a carpel of a dehiscent fruit opens.
Symbiosis : relationship between two organisms where both gain a benefit greater than could be achieved alone, eg nitrogen fixing bacteria in Fabaceae and mycorrhizal associations in 80% of dicots.
Syncarpous : Having the carpels of the gynoecium united in a compound ovary.
Synconium : A compound fruit composed of fruitlets enclosed in a receptacle or peduncle, eg figs.
Tannins : plant polymers that often bind proteins and function as defences against microbes, insects, and many mammals.
Tap root : the main single root axis from which lateral roots develop.
Taxonomy : classification of organisms, including identification and nomenclature, historically based on morphological features and development but more recently also using genetic information.
T-budding : when a single mature bud is inserted into a T-shaped incision in the rootstock; shield budding.
Testa : outer covering of the seed; the seedcoat.
Theca : in angiosperms, a part of the anther, paired, fused sporangia that dehisce via a common slit.
Thinning : removal of some flowers and/or fruits from plants to increase fruit size and quality, and to balance out yields in plants subject to alternate bearing.
Thorn : hard sharp-pointed stem.
Tolerance : ability to survive under adverse environmental conditions or in the presence of a destructive pathogen or pest.
Top working : changing the cultivar of a tree by grafting selected scion material on the trunk or large scaffold branches.
Torus : when used with flowers, the receptacle.
Translocation : movement of water and dissolved substances through the vascular system of plants.
Transpiration : evaporation of water from the surface of leaves and stems.
Trichome : a hair, bristle, scale or other outgrowth from the epidermis.
Tropism : oriented plant growth in response to a directional stimulus from light, gravity or touch.
Tuber : underground stem in which carbohydrates are stored.
Tubercle : a wart-like swelling.
Turgor : firmness of a cell resulting from its hydrostatic or turgor pressure.
Umbel : inflorescence having the flower stalks or pedicels, nearly equal in length, emanating from a common centre or base.
Vacuole : a membrane-bound fluid-filled cavity within a cell.
Variety : a taxonomic subdivision of a species based on minor characteristics and often an exclusive geographic range.
Vascular bundles : strands of primary phloem and xylem separated by the vascular cambium and often surrounded by a bundle sheath found in shoots but continuous with the vascular cylinder of the root.
Vegetative : referring to non-reproductive structures or growth.
Venation : arrangement of veins in a leaf.
Vernalisation : in some species, the period of cold temperature requirement for flowering.
Vesicular-arbuscular mycorrhiza : (VAM) a mycorrhizal association between a fungus and a plant root where the fungal hyphae form vesicles and arbuscules within the plant cell.
Viviparous : Seed germination while the fruit is still on the plant eg ice cream bean.
Water sprout : a vigorous shoot arising primarily from latent buds on the trunk of older scaffold branches.
Waxes : complex mixtures of hydrophobic lipids that make up the protective cuticle that reduces water loss from exposed plant tissues.
Wet feet : a situation where soil remains saturated, excluding natural soil aeration. Soil-borne diseases are favoured under these conditions, often resulting in root decline.
Whip graft : uses scions and rootstocks of similar diameter in grafting.
Whorl : a ring of three or more structures (leaves, stems etc) in a circle, not spiralled.
Wilting : Plant loss of rigidity leading to a flaccid state, due to turgor pressure falling to zero.
Winter chilling : A period of cold, of temperatures 4-8°C which many temperate species need to effectively come into flower and leaf in Spring.
Withholding period : Indicates the time in days between the last spray and the first harvest.
Xenogamy : pollination of one plant by another genetically different plant.
Xerophyte : a drought-tolerant plant.
Xylem : vascular tissue that transports water and ions from the root to other parts of the plant.
Zygote : fertilized egg cell.