active ingredient (= active constituent, or a.c.)
the normal shedding from a plant of an organ that is mature or aged, e.g. a ripe fruit, an old leaf. adj. abscissile, vb. abscise.
a catalogue entry in the order of acquisition, e.g. BRA-xxxxxx (Brazil), CPI xxxxx (Australia), PI xxxxxx (USA).
a reduction in soil pH through leaching and various chemical processes. In extremes this reduces the availability of molybdenum, phosphorus and sulphur but increases the availability of the toxic elements, manganese and aluminium.
arising or developing in a longitudinal sequence beginning at the base and proceeding towards the apex. cf. basipetal.
tapering to a protracted point.
terminating in a distinct but not protracted point, the converging edges separated by an angle less than 90 degrees.
protein or nitrogen that has become chemically linked to carbohydrates to form an indigestible compound. Also referred to as an insoluble crude protein.
arising in abnormal positions, e.g. roots arising from the stems; buds arising from other than axils of leaves.
a parenchymatous tissue with large intercellular spaces within which gasses may be stored and diffused, commonly found in floating plants.
a farming system that integrates crops and/or livestock with trees and/or shrubs.
the integration of soil and plant sciences in growing crops and pastures.
suppression of other species by production of phytotoxic chemicals that inhibit germination and growth of other plants. adj. allelopathic.
soils formed from sediments deposited on land by streams as in a river flood-plain.
the action of making better; improvement, e.g. liming acid soils.
of a plant when bearing both aerial and subterranean fruits. Also amphicarpous. cf. geocarpic.
at the apex or tip.
clonal reproduction through asexual seed formation.
pressed closely against a surface.
herbicide for controlling woody weeds.
curved like a bow.
a space marked out on the surface. adj. areolate: divided in distinct spaces.
jointed; having joints where separation may occur naturally.
growing upward after an oblique or semi-horizontal beginning.
above sea level.
not divisible into similar halves in any plane.
tapering gradually to a slender point.
an ear-shaped appendage at the base of a leaf. adj. auriculate.
the replication of chromosomes by a pure-breeding line to a number of simple multiple of that basic to the species. e.g. an autotetraploid may be derived from a diploid parent by treatment with the alkaloid colchicine which has the effect of preventing the formation at mitosis of two nuclei, thus leaving in one nucleus the two double sets of chromosomes. cf. allopolyploidy.
use of data (e.g. cytogenetic or biochemical) to assess taxonomic relations especially within an evolutionary framework.
an implement comprising a very large sweep or wing blade used for the removal of tree regrowth by underground cutting of roots.
the foliage, tender branches or twigs of trees and shrubs, used as feed for cattle and other animals.
falling unusually early.
growing in tufts.
of soils, relating to a high content of free calcium carbonate, making the soil alkaline.
clustered together in a dense head.
the structure that bears and encloses the ovules in flowering plants.
Cation Exchange Capacity.
a tissue-complex of genetically distinct cells, the result of a mutation within certain cells of a meristem.
a thread-like structure in the nucleus of a cell, containing a linear sequence of genes.
fringed with fine hairs (cilia), as the margins of some leaves.
growing upward, but not self-supporting.
joined in pairs.
heart-shaped (often applied to bases only).
the petals of a flower collectively; usually soft and coloured conspicuously.
a crop planted to prevent soil erosion and to suppress weeds; can also improve soil and/or provide forage.
crude protein - an estimate of the protein value of a feedstuff, calculated by multiplying the nitrogen percentage in the dry matter by 6.25.
a leaf margin with small, rounded teeth; scalloped.
specialised planter used for sowing into a rough, unprepared seedbed. ® External web link.
wedge-shaped. ® Illustration.
systems where feed, crop residues and/or litter is cut and carried to penned or tethered livestock.
commonly called blue-green algae. A photosynthetic bacterium capable of nitrogen fixation in some species.
mineral concretions, usually of calcium carbonate on a cellulose stalk.
strictly, the removal of plant leaves, but generally the removal of herbaceous material, e.g. by grazing, browsing, or cutting.
breaking open at maturity to release the contents.
triangular, with the sides of about equal length.
branching from the same point like the fingers of a hand.
when two surfaces of a leaf are unlike in colour.
the resting or inactive phase of plants or seeds, due to the presence or absence of a growth factor, as of seed when influenced by a need for light or darkness, specific temperature , or after-ripening, or by possession of a coat impermeable to water.
a prolonged period without precipitation during which the soil water content is reduced to such an extent that plants suffer from lack of water.
this rates the ability of a species or strain to survive prolonged periods of dry weather. Ratings assume the species is well adapted to the normal environment, is being utilized each year and is under good management.
dry sheep equivalent. A measure based on the feed requirement of grazing animals, usually used to assess the capacity of land to carry livestock. The standard unit is represented by the ability to maintain a 45 kg wether at constant body weight from one year to the next. Other animals are rated in relation to this. cf. AU.
the first part of the small intestine immediately below the stomach.
a solid (3-dimensional) object elliptical in each rotational plane.
oval in outline, widest at the centre. ® Illustration.
having a broad, shallow notch at the apex.
deriving nutrient from within, e.g. of a mycorrhizal fungus.
the outer layer of cells of a plant. adj. epidermal.
vertical or upright.
a natural process in which nutrients from sediments are carried by runoff into surface waters such as lakes and bays, and provide nourishment for algae in the aquatic ecosystem.
sickle-shaped. ® Illustration.
a farming system in which land is left without a crop for a given period to accumulate soil moisture and release nitrogen from organic matter.
a bundle or cluster, as in grouping of Cenchrus spikelets. adj. fasciculate.
-leaved, as in unifoliate (hence bearing a single leaf).
-leafleted, as in trifoliolate (hence bearing compound leaves comprising three leaflets).
edible parts of plants (other than separated grain) that can provide feed for grazing animals, or that can be harvested for feeding. Increasingly used to refer to the species planted to provide forage.
relative ability to withstand the damaging effect of frost.
of a seed, a supporting attachment (seed stalk).
a reproductive cell (for Angiosperms, pollen and ova).
bent like a knee.
bearing fruit which develops below the soil surface and remains there until germination, as the peanut of Arachis hypogaea . cf. amphicarpic.
having a waxy coating (or bloom) producing a white to blue coloring over the plant parts.
a small compact cluster.
member of the family Poaceae (Gramineae ).
any crop that is grown to add organic matter, nitrogen or other nutrients to the soil.
a plant, usually with a low-growing spreading habit, grown specifically to cover and protect the soil and control weeds.
the ovule-bearing structure of a flower, made up of one or more carpels.
a stalk bearing the gynoecium above the level of insertion of the other floral parts. Sometimes applied incorrectly to the 'peg' in Arachis spp.
the growth form of a plant, comprising its size, shape, texture and orientation.
pasture or crop material that is conserved in a dried state.
pasture or crop material that is dried to about 50% moisture content and is preserved for feeding to animals. Usually the air has been evacuated forcefully, as in an airtight, glass-lined silo, rather than by compression of the stack. cf. silage.
not woody; soft in texture.
an animal that subsists principally or entirely on plants or plant materials.
an organism in which the genes for a specific trait are different. cf. homozygous. (e.g. AaBb).
the scar on a seed coat (testa) at the place where it was attached to its stalk (funicle ) during development.
an organism with identical pairs of genes (or alleles) for a specific trait. cf. heterozygous. (e.g. aaBB).
translucent, almost transparent.
an offspring of genetically different parents.
excessive growth or development due to an increase in the size of the cells.
overlapping on the edges.
= "in bag". Digestibility as measured by suspending a bag containing the feed in the rumen or caecum.
literally, "in glass"; a biologic or biochemical process occurring outside a living organism. cf. in vivo .
literally, "in life"; a biologic or biochemical process occurring within a living organism. cf. in vitro .
not opening at maturity; fruits not opening to release seeds.
the group or arrangement in which flowers are borne on a plant.
a liquid suspension, gel, or peat based material containing live microorganisms (rhizobia, mycorrhizal fungi) that is introduced by inoculation.
growing two or more crops together, planted simultaneously or staggered, with or without a row arrangement.
backcrossing of hybrids of two plant populations to introduce new genes into a wild population.
flooding. In this context, refers to the periodic covering of the soil with water.
the exposure to a radiation, e.g. of wavelengths of light.
pasture receiving supplementary water to maintain growth.
in vitro dry matter digestibility. A laboratory measure estimating the percentage of a feedstuff the animal can digest.
in vitro organic matter digestibility.
of a pinnate leaf when the leaflets are in opposite pairs (jugae). Usually prefixed to indicate the number of opposite pairs, as in uni-, bi-, trijugate.
a ridge like the keel of a boat; in Fabaceae, a boat-shaped structure formed by fusion of the two anterior petals of a flower; in Poaceae, the raised midrib of the leaf sheath.
leaf blade; the expanded portion of a leaf.
lance-shaped; of a leaf, 3 or more four times as long as it is broad, broadest in the lower half and tapering towards both ends. ® Illustration.
the process of returning land to some degree of its former self after it has been damaged by industry, natural disaster, etc.
a measure of solar radiation; equal to one calorie per square centimetre.
loose, not compact.
one of the ultimate segments of a compound leaf.
strictly, a fruit (pod ) characteristic of the families Mimosaceae, Caesalpiniaceae and Fabaceae , but also used as a common name for a plant species in these families.
corky spots on young bark corresponding to epidermal stomata.
like a doubly convex lens.
a pasture phase as part of a sequence of crops for soil nitrogen and organic matter replenishment, soil structure improvement and disease break.
a polymer in the secondary cell wall of woody plant cells that helps to strengthen and stiffen the wall, and a major component of certain plant materials, such as wood, hulls, straws, and over-ripe hays. This fraction is essentially indigestible by animals and is the substance that limits the availability of cellulose carbohydrates in the plant cell wall to rumen bacteria.
very narrow in relation to the length, and with the sides parallel. cf. lorate. ® Illustration.
a closely planted row of shrubs, trees or tall grass grown along boundaries, primarily as a barrier but often used as a source of feed for livestock.
grassland, natural or sown, used as grazing for domestic animals, maintained for a period of 4 or more years.
live weight gain.
of rocks when derived by changes in the properties of pre-existing rocks through forces (e.g. heat and pressure) within the earth's crust.
the process of division of cells in which each daughter cell receives the same amount of DNA as the parent cell.
cylindrical but constricted at regular intervals like a string of beads.
having the male and female structures in separate flowers but on the same plant. cf. dioecious.
the form and structure of an organism or part of an organism; the study of form and structure.
slimy material exuded by certain plants or plant organs. adj. mucilaginous.
terminating abruptly in a sharp point.
a covering used to maintain soil temperature and moisture and to discourage the growth of weeds. e.g. thick layer of plant material.
small free-living or parasitic micro-organisms in the order Mycoplasmatales, indeterminate in size between bacteria and viruses.
a symbiotic union between a fungus and a plant root; the term is often used in reference to the fungus.
a gland which secretes a sweet fluid (nectar).
defined by a significant accumulation of clay (30% or more by mass and extending as much as 150 cm below the surface) and by a blocky aggregate structure. Iron oxides and high water content are believed to play important roles in creating the soil structure. Also nitosol.
a name which, at the time of its publication, was superfluous (because it included the type of an earlier name which should have been adopted) or had already been applied to another plant; abbrev. nom. illeg.
a name published without a diagnosis or description of the entity to which it was applied, and without reference to either.
the tendency of leaves or other parts of a plant to take up different positions at different times, usually in response to regular (esp. nightly) changes in light intensity or temperature. adj. nyctinastic.
longer than broad and with parallel sides, rounded at both ends. ® Illustration.
strictly >90º; of leaves, blunt or rounded at the end.
circular or nearly so. ® Illustration.
the diffusion of liquid through a semipermeable membrane (such as a cell wall) until there is an equal concentration on both sides of the membrane. adj. osmotic.
a cross between relatively unrelated individuals.
egg-shaped, and attached by the wider end. ® Illustration.
egg-shaped (applied to a solid body).
deep, red, highly weathered soils of the tropics without clearly marked horizons.
the relish with which a particular species or plant part is consumed by an animal.
divided into segments like the fingers of a hand; of a leaf, divided into several leaflets which arise at the same point.
of a paper-like texture.
Photosynthetically Active Radiation. An estimate of the amount of visible light available for photosynthesis.
minimization of water loss by reducing the amount of radiation absorbed by the leaves; the leaves orient themselves parallel to the sun's rays.
tissue forming the ground (fundamental) structure of a plant, the cells are actively functioning, usually thin-walled and polyhedral in shape.
grassland, natural or sown, used as grazing for domestic animals.
the stalk of a flower. adj. pedicellate.
a plant whose life cycle extends over more than two growing seasons. cf. annual , biennial.
the stalk of a leaf.
outer layer of non-living suberized (corky) cells of bark.
vascular tissue of plants that conducts synthesised foods e.g. sugars, proteins, through the plant.
the relative lengths of alternating periods of darkness and light affecting the growth and maturity of an organism, as flowering.
an agent occurring in plants which has an effect on unpigmented skins of animals when eaten by them, causing the skin to have an irritated or inflamed reaction when exposed to sunlight.
the effect of light on the direction of growth.
toxic (damaging) to at least some plants.
covered with long, slender soft hairs.
one of a number of first order leaflets of a pinnately compound leaf. pl. pinnae.
soil usually forming in a broadleaf forest and characterised by moderate leaching, which produces an accumulation of clay and, to some degree iron, that has been transported from another area by water. The humus formed produces a textural layer that is less than 50 cm from the surface.
with many different forms.
a natural or modified system of pondage, in which suitably adapted forages are grown in water, primarily for dry season fodder production.
parts per million. = mg/kg.
appearing bitten off at the end.
original or first-formed.
trailing or spreading along the ground but not rooting at the nodes.
estimated maximum yield, which can be sustained when grown in an environment to which it is well adapted.
lying flat on the ground.
the original geographic source of a plant or its propagules.
small sucking insects (Order Homoptera, Family Psyllidae) often causing significant damage to legumes, e.g. Heteropsylla cubana on Leucaena leucocephala and Acizzia sp. on Desmanthus spp.
covered with minute, soft hairs.
covered with short, weak, soft hairs.
dotted or shallowly pitted, often with glands.
the slightly swollen or cup-shaped structure at the tip of the flower stalk (pedicel/peduncle) to which the floral parts are attached (= torus< /A> ).
forming a network.
directed back or downwards.
a generic term for bacteria that live symbiotically in nodules on the roots of legumes and fix nitrogen that is used by the host plants (incl. Bradyrhizobium, Rhizobium, Methylobacterium ).
the part of a soil immediately associated with a root-system.
the large, first compartment of the stomach of a ruminant from which ingested food is regurgitated for rechewing (rumination) and in which digestion is aided by symbiotic microbial action.
cud-chewing mammals such as cattle, sheep, goats, and deer that have a stomach divided into four compartments (rumen, reticulum, omasum, abomasum). cf. monogastric.
soil containing high amounts of soluble salts.
slightly rough to the touch, minutely scabrous.
rough to the touch.
thin and dry, not green.
a plant whose leaves (or stems, if leafless) are hard in texture, usually having thick cuticle and containing many fibres. cf. xeromorph.
a cross-wall or partition.
of a leaf margin, notched on the edge with asymmetrical teeth which point forward.
without a stalk.
covered with bristles.
a pasture phase as part of a sequence of crops for nitrogen replenishment and disease break.
a woody plant, usually less than 3 m high, with many stems from the base.
conserved fodder, harvested while green, and preserved by the formation of organic acids (mainly lactic) in anaerobic fermentation. cf. haylage.
a measure of exchangeable sodium in relation to other exchangeable cations. Plant species vary in their tolerance of sodicity.
the capacity for water to pass through the soil profile.
the ability of a soil to hold and release nutrients for plant growth. In the "Selection Tool", the ratings refer to fertility conditions of the soil as applied in the system, not the natural fertility. "High fertility" relates to those soils that can sustain good plant growth of fertility-demanding species with the addition of little or no Fertilizer. By contrast, "low fertility" relates to those soils requiring significant Fertilizer inputs to achieve productive growth in fertility-demanding species.
process by which salts such as sodium chloride accumulate in a soil profile.
a measure of the total amount of soluble salt in soil, usually measured in terms of conductivity of an extracted solution and expressed in terms of decisiemens per metre (dS/m). See also saline soil , E.C.
a unit of the inflorescence in grasses, consisting of one to many flowers (florets) and associated glumes.
one of the male organs of a flower, consisting typically of a stalk (filament) and a pollen bearing portion (anther ). adj. staminate.
the main axis or a branch of the main axial system of a plant, typically bearing leaves.
a supporting structure or stalk.
having stolons; trailing over the soil surface and rooting at the nodes.
of a leaf; a pore in the epidermis or other aerial organ, providing for gaseous exchange between the tissues and the atmosphere. pl. stomata.
the dried stalks and leaves of a field crop (especially maize) after the grain has been harvested, which can be used as animal fodder.
marked with long narrow ridges or depressions.
with short, stiff hairs lying close to the surface.
narrow and tapering gradually to a fine point. ® Illustration.
of pods, a line of junction or dehiscence between fused carpels.
a relationship between two organisms of different species living together in close association for their mutual benefit.
naturally occurring, astringent tasting plant polyphenols that bind and precipitate proteins. They are found in many legumes and can have a large influence on their nutritive value.
the main, descending root of a plant that has a single, dominant root axis.
a group or category, at any level, in a system for classifying plants or animals. pl. taxa.
cylindrical, circular in cross-section, sometimes in the sense of tapering.
the outer coat of a seed.
of a leaf, having four leaflets.
a response, by movement or growth, to a mechanical stimulus, e.g. leaves of Mimosa spp. closing when touched. adj. thigmotactic.
densely covered with short matted hairs.
a woody plant, at least 3 metres high, usually with an evident trunk.
an epidermal outgrowth, e.g. a hair (branched or unbranched), a papilla.
having three leaves. Sometimes used incorrectly in place of "trifoliolate ".
of a leaf, having three leaflets.
terminating more or less squarely at the end, as though cut off.
a small swelling or rounded protuberance, sometimes found at the base of a hair.
extensively weathered, strongly acid soils of tropical and subtropical climates; often with high levels of exchangeable aluminium.
terminating in a hooked point.
a hoofed animal.
reduced from the ancestral condition and no longer functional.
a measure of the potential for seeds to germinate and grow.
of seed, capable of germination.
colloquial South African term for wetland.
saturated state of a soil profile due to poor drainage.
a ring of leaves, bracts or floral parts borne at the same level on an axis.
a landscape designed with drought -tolerant plants, to eliminate the need for supplemental watering.
vascular tissue that conducts water and mineral salts throughout the plant and provides it with mechanical support.
a more or less massive underground storage structure formed from stems and/or roots allowing resprouting after fire (= lignotuber).