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Parts Of An Embryo Of Dicot Seed Class 10th Science Lab Manual CBSE Solution

Class 10th Science Lab Manual CBSE Solution

Lab Experiment 15
Question 1.

AIM

To identify the different parts of an embryo of a dicot seed (pea, gram or red kidney bean).


Answer:

MATERIALS REQUIRED:


Seeds of Bengal gram /red kidney bean, forceps, cloth, magnifying glass, Petri dish, water.


THEORY


1. A seed is a ripened ovule with a small embryonic plant enclosed in a covering called sees coat, usually with some stored food.


2. The gram seed is formed within a small pod or legume.


3. It is light brown in colour.


4. Its surface may be smooth or wrinkled.


5. The furrow in the middle of seed bears a dark oval patch called chalaza.


6. A seed has following parts, i.e., hilum, seed coat, an embryo, and endosperm.


7. The small oval scar present on the seed coat is called hilum.


8. In between the hilum and pointed end, a small pore called micropyle is present.


9. The seed soaks water through the micropyle during seed germination.


10. The labelled diagrams of pea seed, bean seed, and gram seed are shown below:





PROCEDURE


1. Take few dicot seeds like a pea or red kidney beans and leave them in water for overnight.


2. Next day, drain the excess water and cover the seeds with a moist cloth. Again keep the seeds aside for one day.


4. Then, peel off the seed coat carefully by using a pair of forceps.


5. Open the bean seed using a pair of forceps so that it falls into equal two halves.


6. Using a magnifying glass, try to locate the various parts of the beam embryo carefully.


7. Draw a labeled diagram of the inside of the dicot seed.




OBSERVATIONS

1. A seed coat encapsulates the various components of seed and provides physical protection from the environment.


2. Adjacent to hilum small pore is known as micropyle is present.


3. The embryo consists of two large, white and kidney-shaped cotyledons. The cotyledons are attached laterally to the curved embryonal axis.


4. The upper end of the embryonal axis is called plumule.


5. The part of embryo axis between radicle and attachment of cotyledon leaves is called hypocotyl. And, the part of embryo axis between plumule and attachment of cotyledon leaves is called epicotyl.


6. Rod-shaped and the slightly bulgy lower end of the embryonal axis which lies towards the micropylar end is called radicle.


RESULT



The embryo of dicot seeds consists of three main parts- plumule, radicle, and two cotyledons.
1. Plumule is the upper terminal part of the embryo which elongates and develop into the future shoot.
2. Radicle The lower end of embryo develops into the future root.
3. Cotyledons are also known as seed leaves and contain food for the baby plant.

PRECAUTIONS


1. The cloth which is used to cover seeds should be moist.

2. Seeds coat must be removed using a pair of forceps carefully so that the other part of the seed is not affected.

3. The seed after bisection must be handled with care. 




Viva Questions
Question 1.

Give the difference in seed on the basis of a number of cotyledons?


Answer:

The seed can be divided into two types on the basis of a number of cotyledons:

1. Monocot: having a single cotyledon. Example: corn seed.


Dicot: having two cotyledons. Example: bean seed.



Question 2.

What are the parts in the embryo is differentiated in?


Answer:

The embryo is differentiated in 3 parts:

1. Plumule


2. Radicle


3. Cotyledons
The diagram of a “bean seed” is shown below:



Question 3.

What is Germination?


Answer:

Germination is a process in which a plant emerges from seed and begins to grow.



Question 4.

Define Radicle?


Answer:

The radical is the lower end of the embryo, it develops into the future root.



Question 5.

Define cotyledons?


Answer:

The cotyledon is an embryonic leaf in seed-bearing plants.



Question 6.

What is epicotyl & hypocotyls?


Answer:

i. The part of the embryonic axis between the plumule and the point of attachment of cotyledons is called as epicotyls.


ii. The part of the embryonic axis between the radicle and the point of attachment of cotyledons is called as hypocotyls.


The diagram is shown here:



Question 7.

Why do we soak the seed overnight?


Answer:

Soaking helps the cotyledons to absorb water, and the embryo becomes active.



Question 8.

What is the function of cotyledons?


Answer:

Cotyledons contain food for the baby plant.



Question 9.

Define Plumule?


Answer:

The plumule is the upper terminal part of the embryo which elongates and develop into the future shoot.



Question 10.

What is the function seed coat?


Answer:

The function of seed coat is to protect the seed from harsh temperature & water conditions. Seed coat protects the cotyledons and the embryo during the dormant period.



Question 11.

What are the conditions required for the seed to grow into the complete plant?


Answer:

The condition required are:

1. Water


2. Oxygen


3. Temperature


4. Soil



Question 12.

Mention the different steps of germination of seed in the correct order?


Answer:

1. Absorption of water by seeds.


2. Rupture of the seed coat.


3. Emergence of radical


4. The emergence of plumule.


5. Development of radical into the baby plant.


6. Development of plumule into the shoot.


The diagram is given below:



Question 13.

Differentiate between plumule and radical.


Answer:




Question 14.

What is hilum?


Answer:

It is a scar which is present on the outer surface of a seed, this the point where seed stalk remains attached to the seed.