Question

The part of the embryo between the cotyledons and the embryonic root (radicle) is caved
A. Hypocotyls
B. Epicotyls
C. Plumule
D. Coleorhiza

Answer 1

Hint: The three main portions of a seed are the egg, endosperm, and seed cover. The young multicellular organism produced when it emerges from the seed is an embryo. A seed is an immature plant that retains food and is protected by a protective outer shell, giving birth to a new plant. It is present above the radicle.

Complete answer: The hypocotyl is considered as the portion of the stem of an embryo plant under the stalk of the seed leaves or cotyledons and immediately above the base. The developmental axis that bears the seedling leaves is the hypocotyl in the developing embryo (cotyledons). Upon germination, the hypocotyl forces the cotyledons to grow above the ground. It becomes part of the plant stem ultimately. A mesocotyl spreads the shoot to the soil surface, where secondary roots grow from just below the plumule, the portion of the young plant that lies between the seed (which stays buried) and the plumule. The primary root may then struggle to grow further from the radicle. The mesocotyl is regarded as partially hypocotyl and partially cotyledon. As the cotyledon spreads, the seed coat and endosperm (stored food reserve) are drawn upwards. Later, from the node between the radicle and the cotyledon-like sheath, the first true leaf emerges, cutting through the cotyledon to expand past it.
Hence, the correct answer is option A.

Note: As a storage organ, the hypocotyl becomes swollen in certain plants. Cyclamen, gloxinia and celeriac are some of the examples. This storage organ is called a tuber in the cyclamen. One of the widely used assays in the field of photobiology is the investigation of the effect of changes in light quantity and quality on hypocotyl elongation.