germination

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germination,

in a seed, process by which the plant embryo within the seedseed,
fertilized and ripened ovule, consisting of the plant embryo, varying amounts of stored food material, and a protective outer seed coat. Seeds are frequently confused with the fruit enclosing them in flowering plants, especially in grains and nuts.
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 resumes growth after a period of dormancy and the seedling emerges. The length of dormancy varies; the seed of some plants (e.g., most grasses and many tropical plants) can sprout almost immediately, but many seeds require a resting stage before they are able to germinate. The viability of seeds (their capacity to sprout) ranges from a few weeks (orchids) to up to 1,200 years (sacred lotus) and 2,000 years (date palm). The percentage of viable seed decreases with age. Dormancy serves to enable the seed to survive poor growing conditions; a certain amount of embryonic development may also take place. Dormancy can be prolonged by extremely tough seed coats that exclude the water necessary for germination. Internally, growth is regulated by hormones called auxins. When the temperature is suitable and there is an adequate supply of moisture, oxygen, and light—although some seeds require darkness and others are unaffected by either—the seed absorbs water and swells, rupturing the seed coat. The growing tip (radicle) of the rudimentary root (hypocotyl) emerges first and then the growing tip (plumule) of the rudimentary shoot (epicotyl). Food stored in the endosperm or in the cotyledons provides energy for the early stages of this process, until the seedling is able to manufacture its own food via photosynthesisphotosynthesis
, process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g.
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.

Germination

 

the ability of a seed to yield normal sprouts after a set period of time in defined sprouting conditions. In the USSR seed germination is defined by state seed inspection in controlled seed analysis following a method prescribed by the All-Union State Standard (GOST 12038-66). The number of normally sprouted seeds is expressed as a percentage of the total number of seeds taken for analysis. In defining the usefulness of seeds for planting, germination is one of the most important qualities. This is of great productive importance. Seeds with high germination rapidly and conceitedly yield shoots, guaranteeing large harvests under proper conditions. High seed standards are required for norms of germination, so that first-class seeds of the basic grain crops except for hard wheat must have a germination not lower than 95 percent, and hard wheat must have one not lower than 90 percent. Seeds that do not meet the standard may not be used for planting. Germination depends to a great extent on the techniques of cultivation, method of harvesting, and storing conditions.

M. K. FIRSOVA

germination

[‚jer·mə′nā·shən]
(botany)
The beginning or the process of development of a spore or seed.
(petrology)
References in periodicals archive ?
RG = The Rate of germination, MTG = The Mean time of germination.
Uniformity of germination was calculated according to the following equation [11],
Lettuce germination was significantly affected by the aqueous extracts of C.
A correlation between the extract concentration and the germination percentage for both species, O.
For germination studies, 25 intact, full seeds were placed in a 9 cm plastic Petri dish on a double layer of number one Whatman(r) filter paper.
In general, plant seeds (diaspores) will respond to environmental conditions that favor germination and have a high probability of being followed by other conditions that are favorable for growth and survival of the seedlings (Fenner 1985).
In this equation, FGP is the percentage of marginal germination speed(the germination capacity) and "d" is the number of days before the maximum marginal germination (the duration of experiment).
This index is in contrast with the mean daily germination and is calculated by this formula (Maguire, 1962).
Seeds of certain species that mature in late summer or autumn may be nondormant, but germination may be suppressed by low winter temperature.
1981), suggesting germination occurred there in the past.
With respect to table (1) different aqueous extracts of pine needles had significantly effect on number of roots(NR), shoot length(SL), root length(RL), shoot/root ratio(S/R), seedling length(SeL), dry weight of root(RDW), dry weight of shoot(SDW), dry weight of seedling(SeDW), germination percentage(G), abnormal seedlings(AS), germination inhibition rate(GIR), seedling inhibition rate(SIR) and germination index(GI).