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Glossary
of terms: ABCD
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| Acid: |
a
bitter or sharp substance, having a pH less than 7 e.g. soil that
has a pH of less than 7.5 is considered to be acidic. |
| Aeration: |
providing
air or oxygen to soil and roots. |
| Aeroponics: |
the
cultivation of plants by misting the roots suspended in the air.
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| Air
roots: |
furry, hair-like white roots especially adapted to take up oxygen.
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| Alchemy: |
medieval
fore-runner of chemistry particularly in the conversion of common
elements into gold. |
| Algae:
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collective
name given to plants that grow extensively in water. |
| Alkaline: |
having a pH greater than 7, e.g. soil that has a pH of 7 or greater
is considered to be alkaline. |
| Alkaloids: |
basic organic compounds containing nitrogen. |
| Alternating
current (AC): |
an
electrical current that alters direction several times a second.
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| Amino
acid: |
building
block of protein. |
| Ampere
(amp): |
the
unit used to gauge the strength of an electrical current. |
| Annual:
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a plant that germinates from seed, matures and produces new seeds
in a year or growing season e.g. tomatoes are annuals. |
| Apical: |
of,
at, or being the apex. |
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Aquaculture: |
another
term for hydroponics. |
| Atom: |
the smallest particle of matter possessing the properties of an
element. |
| Auxin: |
plant growth-regulating substance which, among other things, encourages
cell growth by elongation, stimulates cell division thereby encouraging
growth, promotes phototropism by growth towards a light source,
stimulates fruit development, encourages callouses or basal swelling
in wounds, promotes rooting of cuttings, regulates plant height
and induces flower formation. |
| Axillary: |
arising in the angle of a leaf or a bract. |
| Bacteria: |
tiny, unicelled organism. |
| Ballast: |
a
unit that controls the current of electricity and fires up a HID
lamp. |
| Biosynthesis: |
the production of a chemical compound by a plant. |
| Blight: |
diseases
caused by micro organisms where the entire plant is infected and
dies. |
| Blind
water or salts: |
background
conductivity of normal water. |
| Bloom
Boost: |
plant
food that is high in phosphorous and increases yields. |
| Bolt: |
an
unusual lengthening of plant stems due to elongation of cells. |
| Bonsai: |
a
very short or dwarfed plant. |
| Bud
Root: |
a
wasting disease that affects buds. |
| Buffer
7: |
calibration
solution for digital pH meters. |
| Buffering: |
a
chemical substance that stabilizes the pH of a solution. |
| C3,
C4: |
a grouping of higher plants related to the carbon content of the
compound produced when carbon dioxide is fixed during photosynthesis. |
| Calibrate: |
1)
mark a gauge or instrument. 2) compare the readings of an instrument
with those of a standard. |
| Calyx: |
the
pod containing the female ovule and 2 prominent pistils, or seed
pod. |
| CAM: |
crassulacean acid metabolism; a method of photosynthesis found in
certain succulent plants that live in hot, dry climates and close
their stomata during the day to avoid excessive water loss, and
open them at night. |
| Cambium: |
a group of actively dividing cells found in the vascular bundles
of roots and stems whose function is to produce new plant tissue
for lateral growth. |
| Carbon: |
the element which is the basis of organic structure. |
| Carbon
Dioxide: |
(CO2) a colourless, odourless gas, heavier than air which is vital
to plant life. |
| Carbohydrate: |
a
family of organic molecules made up of carbon, hydrogen and oxygen
and include sugar, starch and cellulose. |
| Casparian
Strip: |
a waterproof thickening of the radial (side) and end walls of endodermal
root cells which is thought to influence the route by which water
passes from the cortex into the vascular bundle of the stele. |
| Caustic: |
able to burn or destroy living tissue by chemical activity. |
| Cell:
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the
structural unit of most organisms, cells are bound by a membrane
and contains a nucleus. |
| Cellulose: |
the main constituent of plant cell walls and the most common organic
compound on earth. It fortifies a plant; tough stems contain a lot
of cellulose. |
| CF: |
conductivity
factor of dissolved salts or nutrients expressed as a digital reading. |
| CFM: |
cubic feet per minute. |
| Chelate: |
the
ability for plants to take up metal ions such as iron,. |
| Chemiculture: |
another
term for hydroponics. |
| Chlorophyll: |
a
group of pigments giving a green colour to most plants, which is
found in any part of the plant exposed to light. Clorophyll plants
are usually contained in the chloroplasts of cells. It has the vital
function of absorbing light energy. |
| Chlorine: |
containing chlorophyll and found within the cells of plants leaves
and stems. |
| Chlorosis: |
a
yellowing of leaves caused by lack of chlorophyll pigment due to
a mineral deficiency, usually iron or magnesium, or by disease (virus)
which results in a decrease in photosynthetic rate. |
| Chlorotic: |
describing
a plant that has the condition of chlorosis. |
| Clone: |
1)
a rooted cutting of a plant. 2) 2 or more plants with identical
genetic make-up produced from one parent by asexual propogation. |
| Combination
roots: |
a
mixture of tap water roots and furry air roots. |
| Concentrate: |
very refined chemical which needs dilution on application. |
| Conductivity
Standard: |
calibration solution for digital CF meters. |
| Cork
Cambium: |
a specific cambium that contributes towards the production of bark. |
| Cortex: |
the
layer of plant tissue outside the vascular bundles but inside the
epidermis. |
| Cotyledon: |
first
leaves that appear on a plant after germination. |
| Cross-pollinate: |
the
transfer of pollen from the anthers of one flower to the stigma
of another by the action of wind, insects, etc… with the subsequent
formation of pollen tubes. |
| Crystal:
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1)
the appearance resin has when located on leaves. 2) many compounds
come in soluble crystal form. |
| Cultigens: |
type of plant that depends on human assistance for it’s procreation. |
| Cuticle: |
a thin non-cellular layer secreted by the epidermis and prevents
water loss. |
| Cutting: |
a method of artificial propagation of plants where a small stem,
with attached leaves, is removed at a node from a parent plant,
and placed in water or a moist growing medium. |
| Cystine: |
an
amino acid residue formed by oxidation |
| Damping
off: |
a disease caused by a fungus e.g. pythium in which young seedlings
rot and fall over at ground level in overcrowded, damp conditions,
over-watering is the main cause of damping off. |
| Dead
Salts: |
background water reading of dissolved salts in normal water. |
| Diapause: |
a period of arrested growth and development in insects which is
under the control of the endocrine system. |
| Dioecious: |
in
plants, it is having male flowers carried by one individual and
female flowers carried by another. |
| Direct
current: |
(DC)
an electrical current flowing in one direction only. |
| Drainage: |
removal of excess water, water travels evenly through the growing
medium thereby encouraging plant growth. The opposite is where water
stagnates in the medium effectively drowning the roots. |
| Drip system: |
an
efficient watering system that utilises a hose with small water
emitters. Water is dispensed a drop at a time via the emitters. |
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