Q.Differentiate between:

Let’s take each pair one by one, exactly as the NCERT textbook presents them.

1. Hypocotyl and epicotyl In a dicot embryo, the part of the embryonal axis below the cotyledons is the hypocotyl; it terminates in the radicle. The part above the cotyledons is the epicotyl; it terminates in the plumule. So the hypocotyl is below the cotyledonary node, the epicotyl is above it.
2. Coleoptile and coleorrhiza In a monocot embryo (e.g., grass), the plumule is covered by a protective sheath called the coleoptile. The radicle is similarly covered by a protective sheath called the coleorrhiza. Coleoptile protects the shoot tip; coleorrhiza protects the root tip.
3. Integument and testa The integument is the protective covering layer(s) that surround the ovule before fertilisation. After fertilisation, the integument(s) develop into the testa — the hard, protective outer covering of the seed. So integument is the pre-fertilisation structure; testa is its post-fertilisation derivative.
4. Perisperm and pericarp …

Let’s take each pair one by one, starting with the context of seed structure. A seed, in flowering plants, develops from the ovule after fertilisation. The embryo inside has several regions: the radicle (future root), the plumule (future shoot), and one or two cotyledons (seed leaves). The terms you’ve asked about relate to the embryo’s axis, protective sheaths, seed coverings, and nutritive tissues. NCERT is very precise about these, so we’ll stick to its definitions.

(a) Hypocotyl and Epicotyl

These are parts of the embryo’s axis — the central line that runs from the radicle to the plumule.

The hypocotyl is the portion of the embryo axis below the point where the cotyledons are attached. It terminates at the radicle. In a germinating seed, the hypocotyl elongates and pushes the cotyledons above the ground (in epigeal germination) or remains short (in hypogeal germination). Its key role is to connect the radicle to the cotyledons.

The epicotyl is the portion above the cotyledonary node — that is, above the attachment point of the cotyledons. It ends at the plumule. In germination, the epicotyl elongates to lift the plumule and the first true leaves above the soil.

(b) Coleoptile and Coleorrhiza

These are protective sheaths found in the seeds of monocotyledons (like maize, wheat, rice). NCERT describes them specifically in the context of the monocot embryo.

The coleoptile is a hollow, conical, protective sheath that covers the plumule (the young shoot). It is not a leaf but a specialised structure that guards the delicate shoot tip as it pushes through the soil. Once the shoot emerges, the coleoptile stops growing and the first true leaf breaks through its tip.

The coleorrhiza is a protective sheath that covers the radicle (the young root) in monocot seeds. It is a tough, root-like covering that helps the radicle penetrate the soil. The radicle eventually emerges by rupturing the coleorrhiza.

(c) Integument and Testa

These terms relate to the seed coat — the outer covering of the seed.

The integument is the protective layer that surrounds the ovule before fertilisation. In a typical angiosperm ovule, there are usually two integuments (outer and inner). They cover the nucellus except at the micropyle (a small opening). After fertilisation, the integuments undergo changes — they harden and become the seed coat.

The testa is the outer seed coat that develops from the integument(s) after fertilisation. It is the hard, protective covering of the mature seed. In some seeds, the testa may be thin (like in beans) or thick and woody (like in coconut). The testa is derived entirely from the integument(s) of the ovule. …