Anatomy of Seed
Anatomy of Seed:
• The seed consists of three components:
• embryo, endosperm (sometimes perisperm), and seed-coat.
• Both endosperm and embryo are the products of double
fertilization, whereas the seed-coat develops from the maternal,
ovular tissues.
• Seed:
• In botany, a seed is a plant embryo and food reserve enclosed in a
protective outer covering called a seed coat (testa).
Embryo:
• The embryo is the tiny, immature plant inside a seed, consisting
of:
1. Radicle (primary root): develops into the root system
2. Hypocotyl(stem): connects the radicle to
Functions of embryo:
1. Development into a new plant: The embryo contains the genetic
material and basic structures necessary for the formation of a new plant.
2. Germination: The embryo begins to grow and develop during
germination, breaking through the seed coat and emerging as a seedling.
3. Root development: The radicle (primary root) develops into the root
system, anchoring the plant and absorbing water and nutrients.
Endosperm:
• Endosperm is a tissue found in seeds of flowering plants.
• It serves as a food reserve for the developing embryo.
• It typically contains starch, proteins, and other nutrients that the
growing plant will use during germination and early growth.
Functions of endosperm:
1. Nutrient Storage: Endosperm stores reserves of starch,
proteins, lipids, and other nutrients that provide energy and
building blocks for the developing embryo.
2. Nutrient Provision: During germination, the endosperm
provides the necessary nutrients to support the growth of the
embryo until it can establish its own photosynthetic capabilities.
• Protection: Endosperm surrounds and protects the embryo, providing
a physical barrier against mechanical damage and pathogens.
• Regulation of Germination: Endosperm may also regulate germination
by releasing chemicals that inhibit or promote the process, ensuring
that germination occurs under optimal conditions.
• Protection: Endosperm surrounds and protects the embryo, providing
a physical barrier against mechanical damage and pathogens.
• Regulation of Germination: Endosperm may also regulate germination
by releasing chemicals that inhibit or promote the process, ensuring
that germination occurs under optimal conditions.
Seed coat:
• The outer covering of a seed is called the seed coat.
• Seed coats help protect the embryo from injury and also from
drying out.
• Seed coats can be thin and soft as in beans or thick and hard as in
locust or coconut seeds.
Functions of Seed Coat:
• The seed coat, also known as the pericarp, plays a crucial role in
plant reproduction and seed development. Its main functions
include:
• 1.Protection: The seed coat acts as a physical barrier, protecting
the delicate embryo and endosperm from mechanical damage,
water loss, and pathogens.
• 2. Water regulation: The seed coat helps regulate water uptake
and storage, preventing excessive water absorption and ensuring
proper germination.
• 3.Dormancy: The seed coat can impose dormancy, preventing
premature germination and allowing seeds to remain viable for
extended periods.
• 4.Dispersal: The seed coat can aid in seed dispersal by providing
structures that attract animals or facilitate wind or water
dispersal.
• 5.Nutrient supply: In some cases, the seed coat can provide
nutrients to the developing seedling.
