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Extended glossary


Extended glossary

This glossary gives brief definitions of all the key terms used in the book.


A | B | C | D | E | F | G | H | I | J | L | M | N | O | P | R | S | T | U | V | W | X | Z

A


abscission layer The corky layer that forms at the base of the leaf stalk on deciduous trees sealing off the sap flow in the autumn ready for leaf fall.

achene A non-fleshy single seeded indehiscent fruit

activator A nitrogenous substance that is applied to a compost heap to speed up decomposition. They include poultry manure, horse manure, urine and sulphate of ammonia as well as proprietary products.

adenosine triphosphate (ATP) The major source of usable energy in metabolism. During hydrolysis ATP loses one phosphate to become adenosine diphosphate (ADP) which releases usable energy to the plant.

aeration The permeation of soil by air. Cultivation allows air into the soil and when maintaining turf spiking, slitting or aeration is carried out to allow gaseous exchange between the soil air and atmosphere.

after ripening Where metabolic changes must occur in some dormant seeds before germination will happen. Stratification helps this after ripening to take place.

aggregate fruit A fruit composed of many small fruitlets such as a blackberry, Rubus fruticosus, or raspberry, Rubus idaeus. The fruit develops from several separate carpels of the same flower.

air layering A method of propagating certain plants where a portion of the stem is partially cut or twisted to wound it and then wrapped in a growing medum which is covered with an outer sleeve of polythene tied into place with tape. Once rooted the layer is removed and potted up or planted out.

albino Part of a plant or shoot lacking in chlorophyll that appears a white or bright cream in colour. It is unlikely to survive as a pure albino plant as it cannot photosynthesise its own food.

alien A plant that has been introduced to an area by man and has now become naturalised there.

allotment A small portion of rented land where the tenant can grow flowers, fruit and vegetables for home use. Modern allotments tend to be smaller than during the early 20th century.

alluvial soil One that has formed from the silt left behind by rivers or streams.

alpine plant Originally a plant growing at higher altitudes on mountains, but now used more loosely as plants suitable for rock gardens or similar situations.

alternate host Where a pest or pathogen uses two separate species of plant to complete its life cycle. An example being the black bean aphid that overwinters on Euonymus and its summer host is the broad bean, Vicia faba.

alternation of generations The reproductive cycle in which the haploid (n) phase (the gametophyte) produces gametes which after fusion in pairs form a zygote which germinate to produce the diploid (2n) phase (the sporophyte). Spores produced by meiotic division from the sporophyte give rise to the new gametophytes which completes the cycle.

amino acids Organic acids containing nitrogen in a certain configuration and are used in the construction of protein in the plant as well as other functions.

annual ring The ring of wood developed during each growing season in woody plants; it can be used to estimate the age of the plant.

anthocyanin The pigment in plants that gives the pink, red, purple and blue shades.

antipetaly Where the stamens are arranged opposite to the petals.

areole Small swelling on the surface of plants in the Cactaceae family from which spines, hairs, bristles or wool grow. They arise from a leaf axil and are a modified stem.

aril The fleshy covering of some seeds such as yew, Taxus baccata and spindle, Euonymus europaeus. It is usually brightly coloured to attract birds which eat the flesh and spread the seeds.

awn A bristle-like growth usually hairy that grows from certain parts of the plant like the tips of achenes or sepals e.g. Geranium spp.

axil The upper angle between a branch or leaf and the stem from which it grows.

 

B


bacillus A rod shaped bacterium. These are likely to become widely used as a form of biological control of many pests and possible some diseases. The bacillus kills the pest and lives off the remains.

back cross When crossing the hybrid with one of its parents to ensure certain characteristics are retained in the next generation.

batter Where the face of a hedge slopes inwards from bottom to top which allows the lower leaves to get sufficient light and gives better stability to the hedge.

blanching A practice used to prevent light getting to part or all of the plant which makes it lose its green colour and become white. It is used when growing leeks, Allium porrum and celery, Apium graveolens, to achieve longer white barrels and also when growing chicory, Cichorium intybus, to reduce the bitter taste of the leaves

bract A specialised leaf that performs another function such as protecting a bud or is colourful to attract pollinating insects as in the case of Euphorbia pulcherrima.

brutting The breaking but not severing of young one-year-old shoots of fruit trees to restrict late growth.

bur A growth usually barbed on a fruit or seed that assists with the dispersal of the seed. The bur catches onto the fur or clothing of passing animals or humans; examples being burdock, Arctium spp. and cleavers Galium aparine.

 

C


calcareous and calcicoles Plants that prefer to grow on limey or chalky soils; they have adapted to grow in high pH soils.

calcifuges Plants that prefer to grow in acid soils such as many members of the Ericaceous family.

carotene A yellow or orange pigment in plant tissues which belongs to the carotenoids group and which is found, e.g. in carrots Daucus carota.

catch crop A quick-maturing crop grown on land where a later and usually slower crop is to be planted later in the year.

catkin A spike like inflorescence consisting of unisexual flowers and only found in woody plants such as trees and shrubs.

cellulose The main component of the cell wall of plants which helps to give them some structure and support.

certified stock Plant material (mainly fruit) that has been inspected and is guaranteed to be free from virus infection and other diseases and also true to type.

chipping The damaging of the hard seed coat (testa) before sowing using a knife or file to improve germination. It is used with some cultivars of Sweet pea, Lathyrus spp. and Canna spp.

chitting 1. The sprouting of seed potatoes prior to planting.  The potatoes are placed in trays in a light room with a temperature of approx.10◦C to allow them to sprout ready for planting. 2. Also the partial germination of seed before sowing. This is sometimes carried out with grass seed to get a quicker germination when sowing at the end of a football season to speed up the renovation of the turf. It is done when fluid drilling seeds, again for quicker germination and plant establishment..

chlorosis Where leaves lose all or some of their green colour and usually become yellow or creamish; caused by the loss or reduced development of chlorophyll. It is often caused by nutrient deficiency or diseases and is common in Ericaceous plants growing on soils with a high pH which causes lime induced chlorosis.

cleistogamy Flowers that remain closed in a bud-like state but pollination still takes place within the bud; this can occur in violets. Pollination happens as the anthers and stigmas are close together and the flowers self-pollinate.

cilia Fine hairs on leaves.

coleoptile The outer leaf sheaf of a young grass seedling which protects it as it emerges through the soil.

coleorhiza The protective sheaf around an emerging root of a young grass seedling.

contractile roots Roots that grow down usually from the base of a corm. At the end of the season these roots shrink and pull the new corm that has grown on top of the old one down into the soil. This ensures the corms do not move up to the surface over time.

controlled release A type of fertiliser that releases its nutrients over a set period of time. The time period can vary and is usually indicated on the packet.

cordon A bush or tree trained as a single stem often used in fruit crops. They can be grown upright or at an angle. These types of plants are used in intensive methods of fruit production.

corolla tube Where the petals fuse along their edges to produce a tube like structure as in Narcissi species.

cryptogram A non-flowering plant.

cupule The sheaf of bracts protecting some fruits. Also the cup like structure that holds the nut fruits of the hazel, Corylus avellana and oak, Quercus spp.

 

D


dard A lateral shoot no more than 7.5cm in length on an apple or pear tree with a fruit bud at the tip. The cultivar Bramley’s Seedling is known for producing dards.

day neutral plants Plants that flower regardless of the day length.

deficiency This occurs when the plant or growing media are short of essential nutrients which means the plant cannot sustain healthy growth.

denitrification The conversion of nitrate to gaseous nitrogen which is carried out in the soil by certain bacteria.

determinate Where the main stem ends in a terminal flower or truss which stops the further development of the main stem.

disc flowers The flowers in the centre of many inflorescences of the family Asteraceae; the common daisy, Bellis perennis, being a typical example, the outer florets are made up of ray flowers (the white part) and the inner part being the yellow disc florets.

dot plant A plant used in formal bedding schemes that gives height and contrast to the display.  Plants often used include Fuchsia, Pelargonium, heliotrope, Canna and Eucalyptus.

drought A period of dry weather that can have a negative effect on plants. In Britain it is officially a period of 14 days without measurable rainfall.

drupe A type of fleshy fruit derived from a single carpel and usually contains one seed.

drupelet The individual segment of a raspberry, Rubus idaeus, blackberry, Rubus fruticosus,  or related fruit.

 

E


emasculation The removal of the anthers of a flower to prevent self-pollination.

endocarp The inner most layer of the ovary wall of a fruit which often becomes hard as in the plum, Prunus spp., stone.

epiphyte Plants that attach themselves to other plants but are only using them for support not food sustenance.

espalier A tree, mainly fruit trees, trained against a wall or along horizontal wires. The tree will have one vertical stem with the lateral branches spaced out horizontally approx. 30 cm apart along the wires to the left and right side of the main stem.

 

F


family tree A fruit tree, mainly apples, Malus spp., onto which several cultivars have been grafted.

fan shaped A method of training fruit trees and bushes to keep them restricted and make picking easier. They can be grown against walls or wires supported by stakes.

fasciation Stems become wider and flattened in cross section and sometimes growth is distorted. It is more common in some species than others, Forsythia is fairly commonly affected. It does not appear to do the plant any serious harm and can be pruned out if necessary.

filial generation The hybrid offspring of a cross-bred generation in which the first crossing is denoted as the F1 and the second as the F2 generations.

flocculation Where clay particles come together (flocculate) into crumbs; this happens after an application of lime, calcium sul

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