The document discusses the importance and structure of seeds. Seeds are economically and biologically important as they contain reserves that help with early plant growth. Seeds allow for reproduction and dispersal of plants. Structurally, seeds typically contain a seed coat, endosperm, and embryo. The seed coat protects the embryo, the endosperm stores nutrients, and the embryo develops into a new plant. Key parts of the embryo include the radicle, hypocotyl, epicotyl, cotyledons, and plumule. Seeds play a vital role in plant reproduction and agriculture.

1. Topic
on
Department of Plant Physiology
“ Importance of seed, seed structure & function ”

2.  IMPORTANCE OF SEEDS
1. Seeds are fertilized, mature ovules, the result of sexual reproduction
in plants.
2. Seeds are of immense biological and economic importance.
3. Seeds contain high protein, starch and oil reserves that help in the
early stages of growth and development in a plant.
4. Many cereals and legumes major food sources for a large proportion
of the world’s inhabitants. Rice, barley, wheat and maize are all
seeds.
5. Seeds are the first determinant of future plant development. the seeds
of the key to success in cultivation.
6. Seeds are crucial & essential inputs to increase crop yields per unit
area.
7. Green revolution was only possible with the production of generally
high quality seeds with other qualities, namely high germination , high
vigor, high physical purity & sound health. So the green revolution is
actually the seed revolution.

3. 8. Only seed of assured quality can be expected to respond to fertilizers &
other inputs in the expected manner, other wise the seed of hope may turn into
a seed of frustration.
9. Among the inputs used by farmers for the cheapest input of seed . These are
basic inputs & form a small part of the total cost of cultivation.
10.Quality seed eventually increase the performance of the crop production
factor.
11.Fruits and their seeds as a primary food source.
For example, the diet of many parrots consists predominantly of seed from
native plants such as Banksia, Dryandra and Eucalyptus.

4.  Importance of seeds :-
o Strong germination
o Rapid growth
o Increase crop yield per unit area.
o High vigor
o Tolerance pest & disease.
o Resistance to seed or soil born disease.
o Increase production
o Market value
o Good seed higher crop emergence.
o Good seed requried less seed rate
o Reduce replanting.

5.  Structure of Seed
 Seeds of different plants may vary in many ways, but the basic anatomy
remains the same. A typical seed consists of the following parts:

7.  Testa : It is the outer coat of the seed that protects the embryonic plant.
 Micropyle : It is a tiny pore in the testa that lies on the opposite of the tip of
the radicle. It permits water to enter the embryo before active germination.
 Hilum: Is a scar left by the stalk which attached the ovule to the ovary wall
before it became a seed.
 Cotyledon: In some plants, this contains high quantities of starch and will
provide a source of food for the developing embryo prior to germination, in
other plants this role is performed by an endosperm. In monocotyledons, there
is just one cotyledon whereas in dicotyledons there are two. Depending on the
type of germination (epigeous or hypogeous) the cotyledons may remain
below ground or be pulled above ground.
 Radicle: It is embryonic root which will develop into the primary root of the
plant. It is usually the first part of the embryo to push its way out of the seed
during germination.
 Plumule : This is the embryonic shoot. It appears as a bud which will give
rise to the shoot and the remaining structures in the plant.
 Endosperm: In many plants, a separate part for storage of starch develops and
this is called the endosperm. It is seen in maize and wheat.

8. Functions of Seeds
 They help in germination of the new plant.
 The seeds contain food reservoirs in the form of cotyledons and
endosperm.
 The seed coat is protective in nature which protects the embryo inside.
 Dormancy during unfavorable condition.
 Embryo nourishment :- seed protect & nourish the embryo or young plant.
 It gives seedling as faster start than a sporting of spore, because larger food
reserves in seed.

9. Parts of Seed and Their Functions
 A seed is a structure that encloses the embryo of a plant in a
protective outer covering. Under favorable conditions of growth, a
seed gives rise to a new plant, using the nutrients stored in them.
 The union of the male and female reproductive cells inside the
ripened ovule of a flower helps in the formation of seeds in a
plant. Different seeds have different sizes, shapes, and colors that
participate in the reproduction of flowering plants.
 A typical seed consists of three main parts:
1) seed coat
2) endosperm and
3) embryo.

10. 1. Seed Coat
• They are the protective outer covering of a seed that is usually hard, thick, and
brownish in color. The seed coat is formed from the outer covering of the
ovule called the integument.
• It usually contains two layers:
i) testa – the thick outer layer
ii) tegmen – the delicate inner layer.
• A seed coat has the following four parts:
a) Micropyle – the small opening present at one end of the seed coat,
b) Funiculus – the seed stalk with which the seed is attached to the fruit body,
the integument,
c) Hilum – the region from which the seed breaks off from the fruit, leaving a
scar, and
d) Raphe – the base of the funiculus that is fused with the integument
Functions
 Protecting the seed from physical and mechanical damage.
 Preventing the seed from germination even under favorable conditions of
growth (seed dormancy).
 Acting as a physical barrier against the entry of parasites.

11. 2) Endosperm
• It is a tissue that is rich in oil, starch, and protein. Depending on the presence or
absence of endosperm, seeds are of two types:-
i) Non-endospermic or exalbuminous seeds – Characterized by the complete
absence of the endosperm, such as the seeds of the pea plant, groundnut, and
gram.
ii) Endospermic or albuminous seeds – Characterized by the presence of the
endosperm, such as the seeds of millets, palms, and lilies.
Functions:-
•Storing of reserve foods that provide nourishment to the developing plant.
•Protecting the embryo, the next part of the seed, by acting as the mechanical barrier.

12. 3) Embryo
• They are the young plant that is developing inside the seed coat. An embryo
contains the underdeveloped tissues of leaves, stem, and roots of a plant.
• What are the Parts of an Embryo of a Seed
 Epicotyl – The tiny shoot of an embryo, from which the entire shoot system
develops. The tip of the epicotyl is called plumule.
 Hypocotyl – The stage of transition for the growing shoot and root of the
embryo
 Radicle – The tiny root of the embryo
 Cotyledons – They are the leaves of the embryo that provide nourishment to the
developing plant. There are two types of cotyledons present in flowering plants:
i) monocotyledonous or monocots – embryo with one cotyledon
ii) dicotyledonous or dicots – embryo with two cotyledons.
Functions
•Giving rise to a new complete new plant
•Storing food and nourishing the baby plant

13. .
• Related Articles:
• Howard C . Potts (1971) SEEDS - DEVELOPMENT , STRUCTURE
AND FUNCTION. Page.no.37-51.
• The Parts of a Seed and Their Functions in Seed and Plant Development –
Cropsreview.com