germination


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germination

 [jer″mĭ-na´shun]
the sprouting of a seed, spore, or plant embryo.

germination

/ger·mi·na·tion/ (jer″mĭ-na´shun) the sprouting of a seed, spore, or plant embryo.ger´minative

germination

[jur′minā′shən]
Etymology: L, germen, sprout
1 the initial growth and development of an organism from the time of fertilization to the formation of the embryo.
2 the sprouting of a spore or the seed of a plant. germinate, v.
Germinationclick for a larger image
Fig. 171 Germination . A typical seedling.

germination

the beginning of the growth of a seed, spore or other structure that is dormant. Seed DORMANCY can be broken by several factors, depending on the species:
  1. the removal of a germination inhibitor which can be leached out by water.
  2. a period of cold temperature (STRATIFICATION).
  3. exposure to the correct wavelength of light to stimulate PHYTOCHROMES in the seed, for example, lettuce seeds require red light for germination and are inhibited by far-red light.
  4. rupture of a thick testa by (i) microbial breakdown, (ii) abrasive action of soil (as in desert plants), (iii) heat from bush fires, (iv) the effect of digestive juices (as when eaten by birds), (v) the softening action of water. Once dormancy is broken a regular sequence of events takes place: water is imbibed which hydrates the tissues increasing enzymic action in the ALEURONE layer (when present), a process aided by the release of GIBBERELLIN from the embryo; food stores are mobilized by production of enzymes in the ENDOSPERM or within the COTYLEDONS; AUXINS and CYTOKININS are formed which promote cell division and enlargement, causing the embryo to grow and burst through the testa. See Fig. 171 .

There are two main types of germination, depending on whether the seed cotyledons are carried above the soil (EPIGEAL) or remain below ground (HYPOGEAL).

germination

the sprouting of a seed or spore or of a plant embryo.
References in periodicals archive ?
Increased salinity significantly affected seed germination of R.
First experiment: The germination responses from two seed lots harvested in 2011 and 2012 were evaluated to discriminate the samples with better percentages of seed germination.
Starting on the first day of imbibitions, counts of germinating seeds were made at 12 h intervals as far maximum germination was attained.
For germination, 4 temperature gradients: 15, 20, 25 and 30degC were cultured in the constant temperature incubator.
Therefore, specific stages throughout the ontogeny of the plant, such as germination and emergence, seedling survival and growth, and vegetative and reproductive growth, should be evaluated separately during the assessement of germplasm for salt tolerance.
being minute and containing very little to no nutrient reserve for seed germination (Arditti & Ghani, 2000), orchid seed germination and seedling development are dependent on association of appropriate mycorrhizal fungi as a carbon source.
The normal seedlings resulting from the germination test were used for the determination of seedlings fresh matter, by weighing on a precision scale (0.
In order to evaluate the effect of the pre-germinative treatments of the seeds, the germination test was used, using four replicates of 25 seeds, and the test was carried out according to the Rules for Seed Analysis (RSA) predicted for this species (BRASIL, 2009).
Temperature is another factor that influences the rate of seed germination, ynamics of water absorption, limits and speed of biochemical reactions, in addition to the physiological processes that determine germination (MARCOS FILHO, 2005; CARVALHO & NAKAGAWA, 2012).