Seed in plant

The ovules after fertilisation, develop into seeds. A seed is made up of a seed coat and an embryo.

The embryo is made up of a radicle, an embryonal axis and one (as in wheat, maize) or two cotyledons (as in gram and pea).

The Seed is primarily of two types as follows:

Monocotyledonous Seed (Monocot)

Dicotyledonous Seed (Dicot)

MONOCOT	DICOT

The monocotyledonous seed, has only one cotyledon. There is only one outer layering of the seed coat and seed has the following parts:

Seed Coat	In the seed of cereals such as maize, the seed coat is membranous and generally fused with the fruit wall, called Hull.
Endosperm	The endosperm is bulky and stores food. Generally, monocotyledonous seeds are endospermic but some as in orchids are non-endospermic.
Aleuron layer	The outer covering of endosperm separates the embryo by a proteinous layer called aleurone layer.
Embryo	The embryo is small and situated in a groove at one end of the endosperm.
Scutellum	This is one large and shield-shaped cotyledon.
Embryonal axis	Plumule and radicle are the two ends.
Coleoptile and coleorhiza	The plumule and radicle are enclosed in sheaths. They are coleoptile and coleorhiza.

The dicotyledonous seed, has two cotyledons and has the following parts:

Seed coat	This is the outermost covering of a seed. The seed coat has two layers, the outer testa and the inner tegmen.
Hilum	The hilum is a scar on the seed coat through which the developing seed was attached to the fruit.
Micropyle	It is a small pore present above the hilum.
Embryo	It consists of an embryonal axis and two cotyledons.
Cotyledons	These are often fleshy and full of reserve food materials.
Radicle and plumule	They are present at the two ends of the embryonal axis.
Endosperm	In some seeds such as castor, the endosperm formed as a result of double fertilisation, is a food storing tissue. Examples are bean, gram and pea, the endosperm is not present in the matured seed. They are also known as non-endospermous.

(Structure of Monocot)

(Structure of Diocot)

Structural and geometrical properties such as :

Mass, shape, volume, density, particle size, length, location, porosity, surface roughness and cellularity.