Glossary - Principles of Horticulture - page 278

larva immature stage of some insect

lateral meristem area of cell division within the stem and root responsible for increase in

width

lateral root roots branching from a taproot

lime requirement the quantity of calcium carbonate required to raise the soil pH to 6.5

liquid feed describes a fertilizer solution watered on to soils or composts

manure a source bulky organic matter comprising animal faeces and bedding

molluscicide a pesticide effective against slugs and snails

monoculture where only one species of plant is present

monoecious plants with separate male and female flowers on the same plant

mulches materials applied to the surface of the soil to suppress weeds, modify soil

temperatures, reduce water loss, protect the soil surface and/or reduce
erosion

mutualism a relationship between two organisms which is beneficial to both

mycelium a mass of fungal tissue

native plant present at the end of the last Ice Age when Britain and Ireland separated

from the rest of Europe

naturalized plant introduced by humans and now reproduces in the wild

niche the position or role of each species within a habitat

nymph immature stage of some insect

oedema a dry, corky spotting on leaves and petals of some greenhouse plants caused

by excess root water-pressure

organ a collection of plant tissues carrying out a particular function

osmosis the movement of water from a high water (low solute) concentration to

a low water (high solute concentration) across a selectively permeable
membrane

parasite an extreme form of predation where the predator often lives within the host/

prey

parent material the rock from which a soil is made

perennating organ a storage organ which enables a plant to survive unfavourable seasons e.g.

bulb, corm, tuber

perennial a plant living through several growing seasons

Permanent Wilting Point (PWP) the water content of the soil when a wilted plant does not recover overnight

pesticide a chemical product used to control weeds, pests , and diseases

phloem the tissue which transports sugars made in photosynthesis from the leaves

to other plant organs

photosynthesis the process in the chloroplasts by which green plants trap light energy from

the sun, convert it into chemical energy and use it to produce food in the
form of carbohydrates such as sugars and starch

phyllosphere a community of bacteria and fungi that live on the leaf surface

physical control a material, mechanical or hand control where the weed, pest or disease is

directly blocked or destroyed

pioneer community the first community in the successional sequence

plant disorder a plant condition caused by a non-living factor (such as low temperature)

pollination the transfer of pollen from stamen to stigma of a flower or flowers

population a group of individuals of one species which interbreed

predation a relationship between two organisms which is beneficial to one partner (the

predator) and harmful to the other (the prey)

prickle a sharp pointed outgrowth of the epidermis modified for defence

primary root see taproot