Practical - 4
Aim: Identification of the different parts of an embryo of a dicot seed (pea, gram or red
kidney bean).
Materials Required: water soaked dicot seeds (pea, gram or red kidney beans), cotton
petri dish forceps, needle, brush, simple microscope and slides.
Theory:
1. Seed:Seed is a small embryonic plant present in a safe coating of seed coat, it
stores food.
2. Seed formation:The male gamete of plant, i.e., pollen grains and female gamete
of a plant, i.e., egg cell fuse together to form seed. The seed formation takes
place due to fertilization, and it is the product of reproduction in plants. The
embryo of seed is formed from the zygote.
3. Food in seed:The food is stored in the cotyledons of embryo in some plants and
in the endosperm, a special tissue outside the embryo in other plants. Three
basic parts of a seed:
1. An embryo
2. Nutrient for embryo
3. Seed coat.
4. Cotyledons: It is the seed leaf present in seed. If the embryo has one seed leaf
it is monocotyledon and if it has two seed leaves it is dicotyledon.
Procedure:
1. Take 8-10 soaked seeds of pea gram/red kidney beans and place them on a wet
cotton in a petri dish overnight.
2. The seed coat becomes soft which helps in the opening of the seeds
3. With the help of a forcep, slowly remove the seed coat and study the different
parts of a seed embryo
4. Now, slowly remove the embryo axis with a needle and place it on the slide
5. Observe the different parts of a seed, record your observations and draw labeled
diagrams.
Observations:
1. There is a whitish scar on the darker concave side of a seed called Hilium.
2. The seed has a small dark black pore within the Hilium called micropyle
3. On opening the seed two fleshy leaves called cotyledons are found, i.e., it is a
dicot seed
4. The cotyledons are present inside the hard seed coat called testa and a thin
transparent layer, tegmen
5. Two cotyledons are seen attached at the point of attachment.
6. On the upper end of the embryo axis two very tiny folded green leaves are seen
called plumule (future shoot)
7. Embryo axis at the lower end also contain a outgrowth called radicle (future root)
8. Embryo axis has two parts between the point of attachment, plumule and radicle
which are termed as epicotyl and hypocotyl respectively.
Diagrammatic representation of Dicot seed
Conclusion:
The different parts of an embryo of a dicot seed were identified as plumule (future
shoot), radicle (future root), seed coat (outer covering) and cotyledons (food store)
Precautions:
1. The best quality seeds should be used for study.
2. Soak the seeds overnight to make the seed coal soft.
3. Observe the parts under a simple microscope and record your observations.
4. Remove the seed coat very gently.
