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Imperfectly developed, indimentary, non-functional.
Natural separation of leaves, flowers and fruits from plants. Generally associated with deterioration of a specialized layer of thin-walled cells.
To record in order of acquisition; in the case of seed sources, a numbered seed lot.
Dry, indehiscent fruit containing only one seed.
A soil having a pH less than 7.0 degrees of soil acidity are recognized. Soil is regarded as 'very acid' when the reaction is less than pH 5.0.
actinomorphic ( of flower)
Tapering to a point
adnate See also connate
Joined or attached to; applied to different organs fused during development.
Pressed closely together but not joined. (for example, conifer leaves may be pressed close to the stem of the plant).
Growing from an unusual position (for example, roots from a leaf or stem).
afforestation See also reforestation
1. Conversion of bare land into forest land by planting of forest trees.
2. The planting of a forest crop on land that has not previously, or not recently, carried a forest crop.
A system for mixed arable farming and forestry that has been practised in many parts of the tropics. Tree crops are interspersed with food-crop patches on a continuous basis, sometimes as hedge (often called alley cropping)
agronomic variety See also variety, cultivar
A distinctive seedling popular or clone with enough favourable characteristics to warrant cultivation. Agronomic varieties are given non-Latin names according to priority rules which vary among different crops.
That part of agriculture devoted to the production of crops and the management of the soil on which they are grown. The scientific utilization of agricultural land.
A land-use system in which crops and livestock (but not trees) are the only components.
An agroforestry system for the concurrent production of agricultural crops (including woody perennial crops) and forest crops. The forest crops serve either a productive or a service role. Woody perennial and agricultural crops are chosen first for their productive capacity.
Any agroforestry system that includes trees or shrubs and herbaceous food crops and pastures and animals.
A technique of propagating using an undetached stem to which the rooting medium is applied by securing it in an appropriate container, for example, a polythene bag.
air-dry soil See also oven-dry soil
Soil that has been spread out to dry, usually in thin layers in the shade, until it reaches a constant weight. Final water content may vary somewhat with environmental conditions. Applies also to plant materials that often can be sun dried.
1. A soil having a high degree of alkalinity (pH of 8.5 or higher) or having a high exchangeable sodium content (15% or more of the exchange capacity) or both. When saline soils are leached, and if calcium levels are low, exchangeable calcium is replaced by sodium and the soils become highly alkaline and deflocculate.
2. A soil that has such a high a degree of alkalinity or percentage of exchangeable sodium, or both, that the growth of most crop plants is reduced. This is true if the pH is 8.5 or higher, or if the percentage of exchangeable sodium is 15% or more. Such soils are highly dispersed so that air and water movements are very slow. In popular usage, saline soils have been called 'white alkali' soils. True alkali soils, because of dispersion of the organic matter, have been called 'black alkali' soils.
alkalinity See also salinity
Amount of cations balanced by weak acids expressed as milli-equivalents of neutralized hydrogen ions in 1 litre of water.
Applied to a stand in which, theoretically, trees of all ages are found, including those of felling age.
1. An interaction between different plants or between plants and micro-organisms in which substances (allelochemicals) produced by one organism affect the growth of another (usually adversely).
2. The suppression of germination or growth or the limiting of the occurrence of plants, as a result of the release of chemical inhibitors by some plants.
3. The influence of plants (other than microorganisms) upon each other arising from the products of their metabolism.
An agroforestry intercropping system in which species of shrubs or trees are planted at spacings relatively close within row and wide between row, that is, in the 'alleys', to leave room for herbaceous cropping between.
Soil developed from transported and relatively recently deposited material (alluvium) characterized by little or no modification of the original material by soil-forming processes.
1. Clay, silt, sand, gravel pebble or other detrital materials deposited by water.
2. A sediment deposited by streams and varying widely in particle size. The stones and boulders, when present, are usually rounded or subrounded. Some of the most fertile soils are derived from alluvium of medium or fine texture.
The application of horticulture practices for leisure-oriented or aesthetic purposes.
The biochemical process in which ammonical nitrogen is released from organic compounds containing nitrogen.
androecium See also gynaecium
A collection of stamens that form the male reproductive organs of a flowering plant. These may be borne together with the female reproductive organs within the same flower of an individual plant
annual plant See also seasonal plant
A plant that completes its life cycle within 1 year.
The opening of a flower bud; the exposure of stamens and stigmas to pollinating agents; the span of life of a flower.
The pigment usually responsible for pink, red, purple, violet and blue colours in flowering plants.
Irregular dead areas on leaf margin, between and across and/or along veins, often moving onto the shoots and small twigs; sometimes whole leaves are engulfed.
apex (adj. apical)
The tip of an organ; the growing point.
The control of tree crown development in which interactions between shoots determine branch elongation.
The control over lateral bud or shoot development exerted by plant growth regulators from a shoot apex in the current year of growth.
The growing point of the plant. The tissue at the tip of the stem or root in which cells undergo division.
With carpels free from each other.
Reproduction in which sexual organs or related structures develop as seeds but fertilization does not occur, so that the resulting seed is vegetatively produced.
Fish farming. In a broad sense, producing any product under water, for example, algae (seaweed), crustaceans (shrimp).
See arable land.
Refers to land under crops, land under temporary meadows for mowing or pasture, land under market and kitchen gardens (including cultivation under glass) and land temporarily fallow or lying idle. Hence 'arable farming'.
A general term for the cultivation of trees.
A fleshy or sometimes hairy outgrowth from the hilum or funicle of a seed.
asexual, asexual regeneration
Propagation of plants from vegetative parts, such as stems, leaves or roots; or from modified stems such as bulbs, tubers, rhizomes and stolons. This is accomplished without union of gametes.
In plant morphology: growing narrower toward the base, or sometimes toward the tip.
auricle (adj. auriculate)
Small ear-like projections at the base of a leaf or leaf blade or bract.
Self-fertilization in plants.
A phytohormone involved in many physiological processes including root and stem elongation, fruit set, cambium activity and sex determination. Indoleacetic acid (IAA) is the major naturally occurring auxin.
Growing in the axil, which is the angle between the upper side of the leaf and the stem.
axillary bud See also axillary
A bud borne laterally on the stem in the axil of a leaf.
The main or central stem of a herbaceous plant or of an inflorescence.
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