Q.Draw the labelled diagram of the following:

(i) Gram seed (dicot seed) — a seed with two cotyledons, enclosed by the seed coat and containing the embryo.

• Seed coat — the outermost covering, made of an outer testa and an inner tegmen.
• Hilum — a scar on the seed coat marking where the seed was attached to the fruit.
• Micropyle — a small pore lying just above the hilum.
• Embryo — consists of an embryonal axis and two thick, fleshy cotyledons which store food.
• Radicle and plumule — the two ends of the embryonal axis (radicle towards the micropyle, plumule at the other end).

(ii) V.S. of maize seed (monocot seed) — a one-cotyledon seed in which the food is stored in the endosperm.

• Seed coat (husk) — the membranous covering, fused with the fruit wall (as the maize 'seed' is really a fruit).
• Endosperm — bulk of the seed, a food-storing tissue; its outer proteinaceous layer is the aleurone layer.
• Embryo — small, lying to one side of the endosperm.
• Scutellum — the single shield-shaped cotyledon. …

(i) Labelled diagram of a gram seed (a dicotyledonous seed)

A gram seed is a good example of a non-endospermic (ex-albuminous) dicot seed, where the reserve food is transferred to and stored in the cotyledons. The parts to be labelled are:

• Seed coat — the outermost protective covering of the seed, differentiated into an outer, harder testa and an inner, thinner tegmen.
• Hilum — a scar on the seed coat through which the developing seed was attached to the fruit.
• Micropyle — a small pore present above the hilum.
• Embryo — made up of an embryonal axis and two cotyledons.
• Cotyledons — two thick, fleshy structures that store food for the developing seedling.
• Radicle — the lower end of the embryonal axis, lying towards the micropyle; it forms the future root.
• Plumule — the upper end of the embryonal axis; it forms the future shoot.

(ii) Labelled diagram of the V.S. of a maize seed (a monocotyledonous seed)

The maize grain is botanically a fruit in which the seed coat is fused with the fruit wall. It is a typical endospermic (albuminous) monocot seed where the food is stored in the endosperm. The parts to be labelled in a vertical section are:

• Seed coat / husk — a membranous covering that is generally fused with the fruit wall (pericarp).
• Endosperm — a large, food-storing tissue forming the bulk of the grain; its outermost layer is the proteinaceous aleurone layer.
• Embryo — small in size, located in a groove on one side of the endosperm and separated from it by the scutellum.
• Scutellum — the single, shield-shaped cotyledon of the maize embryo. …

Method: Building Each Seed Diagram by Answering Four Structural Questions

Instead of memorizing two separate lists of labels, draw each seed by answering the same four questions in sequence. The answers differ between gram and maize, but the questions are identical, which makes the two diagrams easy to compare and remember together.

Question 1, what covers the seed? Gram has a distinct seed coat (outer testa plus inner tegmen), visible with a hilum scar and a micropyle beside it. Maize has a thin, membranous covering fused to the fruit wall, because the maize "seed" is really a fruit, so draw one combined outer layer, not a separate testa/tegmen.

Question 2, where is the stored food? Gram stores food in the two cotyledons themselves, drawn thick and fleshy, filling most of the seed. Maize stores food in a separate endosperm tissue, drawn as the bulk of the grain, with a thin aleurone layer as its outer boundary.

Question 3, how many cotyledons, and what shape? Gram has two, roughly equal, fleshy halves. Maize has one, shield-shaped cotyledon called the scutellum, tucked to one side against the endosperm. …