Glossary of terms

Calcareous soils: Soils containing large amounts of lime, usually calcium and magnesium carbonates.

Chlorophyll: Green pigments located in the chloroplasts of the plant; responsible for the absorption of light energy which is essential for photosynthesis.

Chlorosis: Reduced development or loss of chlorophyll.

Dry weight: Moisture-free weight obtained by oven drying.

Essential elements: Inorganic elements of the soil and air required by plants for healthy growth and development.

Hydroponics: Growth of plants in water to which essential elements have been added.

Internode: The region of the stem between any two nodes.

Interveinal: Between the veins.

Leaf: Single member of plant foliage consisting of a green blade and petiole.

Macronutrient A chemical element essential for healthy plant growth and

(or major element): required in the tissues in relatively large amounts (0.1 per cent of the dry matter or greater).

Metabolism: The sum total of the chemical processes that occur in the plant.

Micronutrients A chemical element essential for healthy plant growth and

(minor elements required in the tissues in relatively small amounts (less than

or trace elements): 1000 ug/g dry matter).

Midrib: A ridge of tissue occurring along the main vein of the leaf.

Necrosis: Death of a section of tissue.

Node: The region of the stem where one or more leaves are attached. Buds are commonly borne at the node in the axils of the leaves (see Internode).

Petiole: The stalk of the leaf.

Phloem: Tissue located in the bark and associated with the transport of sugars and some mineral elements from one part of the plant to another.

Phloem - immobile Inorganic elements that do not move readily in the phloem.

elements: Examples include calcium, boron, copper, iron, manganese and zinc.

Phloem - mobile Inorganic elements which can be transported in the phloem such

elements: as from leaves to fruit or from old leaves to young leaves. Examples include nitrogen, phosphorus, potassium, and magnesium.

Photosynthesis: The production of sugar from carbon dioxide and water in the presence of chlorophyll using light energy and releasing oxygen.

Solution culture: See hydroponics.

Species: A group of closely related individuals; the unit of plant classification.

Translocation: The movement of sugars, water and elements from one part of a plant to another.

Transpiration: The loss of water from plant tissue in the form of vapour.

Turgor: The swollen condition of a cell caused by internal water pressure.

Variety: A subdivision of a species.

Vascular tissue: Tissue composed of xylem and/or phloem, the conducting tissues of the plant.

Vein: Vascular tissues forming part of the network of conducting and supporting tissues of the leaf or other expanded organs.

Veinal: On or associated with the veins.

Wood: The rigid portion of the vascular tissue containing the xylem.

Xylem: Tissue associated with the movement of water and mineral nutrients from roots to leaves, and fruit. All inorganic elements move freely in the xylem.