Epigeal Germination vs. Hypogeal Germination
Key Differences
Comparison Chart
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Cotyledon
Photosynthetic Cotyledons
Energy for the Embryo Development
Structure
Occurrence
Epigeal Germination vs. Hypogeal Germination
In epigeal germination, the cotyledons appear out of the soil during germination whereas, in hypogeal germination, the cotyledons stay inside the soil. Hypocotyl shows a more elongation in epigeal germination whereas the hypocotyl is short in hypogeal germination. The hypocotyl is lengthy in plants that show epigeal-germination while the hypocotyl is small in plants that show hypogeal germination. The upper part of the hypocotyl is curving down to keep the plumule in epigeal germination while hypocotyl in hypogeal germination does not show this curvature. The hypocotyl is elongating in epigeal germination whereas Epicotyl is extending in hypogeal germination. Epicotyl is short in plants that display epigeal germination while the epicotyl is long in plants that show hypogeal germination. The terminal of hypocotyl is curving to guard the cotyledon in epigeal germination whereas the terminal of the epicotyl is curving to protect the plumule from hypogeal germination. The cotyledons in epigeal germination turning green and undergo photosynthesis while the cotyledons in hypogeal germination do not experience photosynthesis. In epigeal germination, the energy originates from the cotyledons, while, in hypogeal germination, the energy originates from the endosperm. Epigeal germination occurs in beans and castor whereas the hypogeal germination occurs in pea, coconut, and maize.
What is Epigeal Germination?
Epigeal germination is the kind of germination in which the seed leaves and cotyledons increase out of the soil owing to the elongation of the hypocotyl along with the development of the shoot. The hypocotyl is the fragment of the stem of an embryo plant beneath the stalks of the cotyledons. During the epigeal germination, the hypocotyl raises quickly and actively and becomes curve or curl in appearance. After emerging out of the soil, change in the hypocotyl flattens which allows the seed leaves or the cotyledons to come on which become photosynthetic as well. This effect in the seed coat to fall off, the cotyledons seem to green. The second leaves derive from the plumule become true leaves. The epicotyl ultimately matures and give rise to complete green leaves, and the cotyledons fall off. The main features of epigeal germination are; the radicle develops first to form the hypocotyls, but the plumule develops late. The hypocotyl primarily forms a loop and then extends. The cotyledons are carrying to the surface and thereby produce the primary leaves follow by shoot development.
Examples
Epigeal germination occurs in cotton, onion, castor, papaya, etc. In addition to food storage, cotyledons experience photosynthesis and produce food for the development of the embryo.
What is Hypogeal Germination?
Hypogeal germination is the type of germination in which the cotyledons persist below the soil surface, and this is due to the fast development and elongation of the epicotyl. Therefore, its hypocotyl is short. The epicotyl primarily develops, and then it extends, follows by curling up and attaining a curve structure and results in the cotyledons to stay below the soil surface. The epicotyl, which is the area of an embryo plant above the cotyledon, grows elongating while pushing the plumule out of the soil. The main features of hypogeal germination are; It is the type of an in situation seed germination where the cotyledons stay in the soil. The radicle grows to form the root system. The plumule progresses into the shoot system.
Examples
All monocotyledons such as rice, wheat, maize, and coconut show hypogeal germination. Also some dicotyledons such as groundnut, gram and pea show hypogeal germination.
