Glossary - Seed Testing - page 326

Seedborne. Carried on or in seeds.
Seed coat. The protective covering of a seed usually composed of the inner and outer integu ments. Also
called the testa.
Seed coating. Application of substances such as fungicides, insecticides, safeners, micronutri ents, etc.
directly to the seed that do not obscure its shape.
Seedling. A young plant grown from seed.
Seed pellet. Obscuring the shape of the seed with an amalgam of illers and cementing additives (some-
times containing other substances such as plant growth regulators, inoculants, fungi cides, etc.) to a
speciic size to enhance mechanical planting and seed performance.
Septum. A partition, as between the locules of a fruit.
Sillique (sillicle). A fruit, characteristic of the mustard family, which has two valves that at maturity split
away from a persistent central partition. If it is several times longer than wide it is termed a sillique. If
it is broad and short it is called a sillicle.
Simple cyme. The simplest branched determinant inlorescence where the lateral lowers de velop later than
the terminal lower (e.g., mouse-eared chickweed).
Simple fruits. Developed from a single pistil or ovary that may be simple or compound (e.g., berry, as in
blueberry).
Solanad embryo type. A type of embryo classiication in which the terminal cell of the proem bryo divides
by a transverse wall and in which the basal cell plays a minor part (or no part) in subsequent embryo
development.
Solid matrix priming. Hydrating seeds in low water potential solid carriers such as clays or vermiculite
followed by subsequent drying to enhance germination, stand establishment, and seedling growth
(also known as matriconditioning).
Solitary lower. The simplest expression of a determinant inlorescence.
Somatic cells. Pertaining to cells of the plant body other than reproduction tissue.
South Dakota blower. A popular type of seed blower used in purity testing of seeds. Air is passed through
plastic tubes to help in the separation of seeds according to their speciic gravity and resistance to air
low.
Sperm cell. The male generative cell that fertilizes the egg cell and unites with the polar nuclei.
Spadix. A special type of spike with a leshy inlorescence axis.
Spathe. A large bract surrounding an inlorescence, especially a spadix.
Spike. A basic type of inlorescence in which the lowers arising along the rachis are essentially sessile
(stalkless).
Spikelet. The unit of the grass lower that includes the two basal glumes subtending one to several lorets.
Spore. In seed plants, the spore is the irst cell of the gametophyte generation. The two kinds, microspore
and megaspore, produce male and female gametes, respectively.
Stamen. The part of the lower bearing the male reproductive cells composed of the anthers on the ilament
(stalk).
Stigma. The upper part of the pistil that receives the pollen.
Stratiication. The practice of exposing imbibed seeds to cool (5-10°C) temperature conditions for a few
days prior to germination in order to break dormancy. This is a standard practice in germination testing
of many grass and woody species.
Strophiole. A rare appendage arising from the seed coat of some species near the hilum area. It may be
variable in shape and has no apparent function.
Style. The stalk of the pistil between the stigma and the ovary.
Subsampling. The procedure (usually by halving methods) by which a smaller representative working
sample is obtained from the larger sample submitted for seed analysis.
Suspensor. The group or chain of cells produced from the zygote that pushes the developing proembryo
toward the center of the ovule in contact with the nutrient supply.