Agriculture Reference
In-Depth Information
Capsule. A dehiscent fruit with a dry pericarp usually containing many seeds.
Carpel. Female reproductive organ of lowering plants. One or more carpels may be united to form the
pistil.
Caruncle. A fragile appendage or outgrowth of the outer integument of the seed of some species (e.g., leafy
spurge).
Caryopsis. A dry, indehiscent one-seeded fruit (as in grasses) in which the pericarp and integuments are
tightly fused.
Catalase. An enzyme that catalyzes the degradation of hydrogen peroxide to water and the oxidation by
hydrogen peroxide of alcohols to aldehydes during seed germination.
Catkin. A spike inlorescence with a single unisexual lower arising from the peduncle, as in Alnus rubra
(red alder).
Caveat emptor. A Latin expression meaning “let the buyer beware,” often applied to seed marketing prior
to the consumer protection era.
Cellular endosperm. A type of endosperm in which the early development is characterized by cell wall
formation accompanying each nuclear division.
Cellulose. A long-chain complex carbohydrate compound (polysaccharide) with the general formula
(C 6 H 12 O 6 )n. It is the chief substance forming cell walls and the woody parts of plants.
Certiied seed. Seed produced under an oficially designated system of maintaining the genetic identity of,
and including provisions for, seed multiplication and distribution of crop varieties. It also refers to the
class of certiied seed which is the progeny of registered or foundation seed. It is identiied by a blue
tag; thus, it is sometimes called “blue-tag” seed.
Chalaza. The part of an ovule where the integuments originate. In orthotropous ovules the chalaza is
directly underneath the funicular attachment. In other types of ovule arrangement it can sometimes be
distinguished on the outside of the seed near the hilum (e.g., campylotropous (legumes)).
Chromosome. A rodlike bearer of hereditary material (genes) inside the nucleus of all cells.
Chenopodiad embryo type. A type of embryo classiication in which the terminal cell of the pro-embryo
divides by a transverse wall and both the basal and terminal cells contribute to embryo development.
Circadian rhythm. See endogenous rhythms. A type of rhythmic plant or animal growth response which
appears to be independent of external stimuli.
Circinotropous ovule. A type of ovule arrangement in which the funiculus is very long and completely
encircles the ovule, which otherwise has an orthotropous (straight) arrangement.
Circumscissle capsule. A capsule which at maturity splits open at the middle so that the top comes off like
a lid (e.g., plantain).
Cold test. A type of stress (vigor) test that tests the performance of seeds in cool, moist soil in the presence
of various soil microorganisms. The test is conducted by planting the seeds in moist, unsterilized ield
soil, exposing them to cool (5-10°C) temperatures for about a week, then allowing them to germinate
in the same soil at warmer temperatures.
Coleoptile. A transitory membrane covering the shoot apex of certain species that protects the plumule as
it emerges through the soil. The coleoptile is photosensitive and stops growth when exposed to light,
allowing the plumule to break through and continue growth.
Coleorhiza. A transitory membrane covering the emerging radicle (root apex) in some species. It serves the
same function for the root as the coleoptile does for the plumule.
Coma . A tuft of hairs attached to a seed (e.g., “brush” on wheat).
Complete lower. A lower that has pistils, stamens, petals and sepals.
Complete hybrid. A legal designation for a seed lot indicating that at least 95% of the seed represents
hybrid seed.
Compound cyme. A determinate inlorescence where there is secondary branching, and each ultimate unit
becomes a simple cyme (e.g., Sapanoria oficinales ) .
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