explain the following terms
1. epicotyl
2.plumule
3.radicel
4.hilum
5.coleoptile
6.aleurone layer
7.testa
8. germination.
Answers
Explanation:
1. epicotyl - An epicotyl is important for the beginning stages of a plant's life. It is the region of a seedling stem above the stalks of the seed leaves of an embryo plant. It grows rapidly, showing hypogeal germination, and extends the stem above the soil surface. A common misconception is that the epicotyl, being closer to the apex of the plant, is the first part to emerge after germination - rather, the hypocotyl, the region of the stem between the point of attachment of the cotyledons and the root - forms a hook during hypogeal germination and pushes out of the soil, allowing the more delicate tissues of the plumules and apical meristem to avoid damage from pushing through the soil. The epicotyl will expand and form the point of attachment of the shoot apex and leaf primordia or "first true leaves". Cotyledons may remain belowground or be pushed up aboveground with the growing stem depending on the plant species in question.
2.plumule - 1: the primary bud of a plant embryo usually situated at the apex of the hypocotyl and consisting of leaves and an epicotyl
2: a down feather
Answer:
Epicotyl :- An epicotyl is important for the beginning stages of a plant's life. It is the region of a seedling stem above the stalks of the seed leaves of an embryo plant. It grows rapidly, showing hypogeal germination, and extends the stem above the soil surface.
Plumule :- Plumules are generally defined as the part of a seed embryo. It is a bud like or a small portion of the plant embryo giving rise to the first true leaves, especially above the cotyledons and is grown into a plant giving rise to several leaves, branches, flowers, and seeds.
Radicle :- In botany, the radicle is the first part of a seedling to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil. Above the radicle is the embryonic stem or hypocotyl, supporting the cotyledon. It is the embryonic root inside the seed.
Hilium :- In botany, a hilum is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus. On a bean seed, the hilum is called the "eye". For some species of fungus, the hilum is the microscopic indentation left on a spore when it separates from the sterigma of the basidium.
Coleoptiles :- Coleoptiles are cylindrical organs that ensheath the first leaf and shoot apex in grass seedlings. They help in the emergence of the first leaf (and shoot apex) by protecting it during its passage through the soil. On emergence, the first leaf breaks through the coleoptile tip.
Aleurone layer :- Aleurone is a protein found in protein granules of maturing seeds and tubers. The term also describes one of the two major cell types of the endosperm, the aleurone layer. The aleurone layer is the outermost layer of the endosperm, followed by the inner starchy endosperm.
Testa :- The product is a structure in which the embryo is protected from temperature extremes by its state of desiccation and is often guarded from further drying and from mechanical or biological degradation by the seed coats.
Germination :- Germination is usually the growth of a plant contained within a seed; it results in the formation of the seedling. It is also the process of reactivation of metabolic machinery of the seed resulting in the emergence of radicle and plumule.