Horticulture Principles and Practices

Cellulose A complex carbohydrate that forms a major
part of plant cell walls and provides strength to
stems and other parts.
Central leader A training method for trees in which a
central axis is maintained.
Certified seed An increase in quantity of foundation
seed certified by an approved certifying agency.
Chilling injury Direct and or indirect injury to plants
or plant part from exposure to low, but abovefreezing
temperatures.
Chlorosis A mineral deficiency symptom in which
affected plants show yellowish or greenish-yellow
coloration in their leaves.
Clay One of the three primary soil particles; it has
extremely small particles with colloidal properties.
Climacteric The period in the development of some
plant parts involving a series of biochemical changes
associated with the natural respiratory rise and
autocatalytic ethylene production.
Clod A hard, artificially produced (e.g., by tillage)
lump of soil that is difficult to break.
Clone A plant that is asexually propagated from
another; both plants are genetically identical.
Cold frame An enclosed, unheated structure covered
on top with glass or plastic used to harden off plants
or protect tender plants during the early spring.
Cold-hardiness The minimum temperature at which a
plant can survive (tolerance).
Cole crop Vegetables of the genus Brassica.
Colloid Very fine organic or inorganic particles that
are interspersed.
Common name The English name of a plant that may
differ in various localities (e.g., maize and corn).
Compaction Excessive packing or settling of a
growing medium.
Companion crop A crop planted along with another
but harvested separately. The two crops positively
impact each other.
Compatibility Ability of different species to be sexually
or physically united and grow together as one.
Compensation point (light) The light intensity at
which the rates of photosynthesis and respiration are
equal.
Complete fertilizer A compound fertilizer containing
a mixture of nitrogen, phosphorus, and potassium.
Complete flower A flower with both male and female
parts; sexually complete.
Compost A soil amendment consisting primarily of
decomposed organic matter.
Compound leaf A leaf composed of more than one
distinct leaflet.
Container growing Growing plants to mature size in a
container; also called pot gardening.
Cool-season plant A plant species that is frost tolerant
and prefers daytime temperatures ranging from 15 to
18°C (60 to 65°F).
Cork cambium The layer of meristematic cells that
produces bark on woody plants.
Corm A short, swollen, and vertically growing
underground stem that stores food.
Cormel A young offshoot produced by a larger corm.
Corolla The collective term for all petals on a flower.
Cotyledons Leaflike structures at the first node of the
seedling stem.
Cover crop A fast-growing crop grown primarily for
the purpose of covering a bare soil.
Crop rotation Planting different species of crops in an
area in a planned sequence, year after year, to
prevent buildup of diseases or insects associated
with particular crops.
Cross-pollination The transfer of pollen from the
stamen of one flower to the stigma of a flower on
another plant.
Crown The root-stem junction of woody plants; also
the region at the base of the stem of herbaceous
species from which branches or tillers arise.
Cultivar Derived from the words cultivated and
variety, often designating a product of plant
breeding.
Cultural control A method of pest control involving
manipulation of the growing conditions of the plant.
Cut flower A flower grown for the sole purpose of
cutting and displaying in a vase or other
arrangement.
Cuticle An impermeable surface layer on the
epidermis of plant organs.
Cutting A vegetative plant part used for propagation.
Cytochrome A class of several electron-transport
proteins serving as carriers in mitochondrial
oxidation and in photosynthesis electron transport.
Cytokinesis The division of the cytoplasmic
constituents during cell division.
Cytokinin A naturally occurring plant hormone
involved in activities such as cell division, organ
initiation, breaking dormancy, and other activities.
Cytoplasm The living material of the cell, exclusive of
the nucleus, consisting of a complex protein matrix
or gel.
D
Damping-off A disease in which a soilborne fungus
attacks seedlings soon after germination at the soil
line and kills the plants.
Day-neutral plant A species that flowers regardless of
the dark to light ratio.
Deciduous A plant that sheds its leaves in fall.
Decomposition The breakdown or rotting of plants or
animals.
Defoliation The dropping of most or all leaves from a
plant.
Dehiscence The splitting open of mature pods.
Desuckering The removal of suckers from a plant.
Glossary 747