Seeds Structure and Germination Long Answer Biology Class-9 ICSE Selina Publishers

Seeds Structure and Germination Long Answer Biology Class-9 ICSE Selina Publishers Solutions Chapter-6. Step By Step ICSE Selina Concise Solutions of Chapter-6 Seeds Structure and Germination with Exercise-6 including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type and Structured/Application Questions Solved Visit official Website CISCE for detail information about ICSE Board Class-9.

Seeds Structure and Germination Exe-6 Long Answer Biology Class-9 ICSE Concise Selina Publishers

Board ICSE
Publications Selina Publication
Subject Biology
Class 9th
Chapter-6 Seeds-Structure and Germination
Book Name Concise
Topics Solution of D. Long Answer Type
Academic Session 2023-2024

D. Long Answer Type

Seeds Structure and Germination Class-9 Biology Concise Solutions  

Page 56

Question 1.

Distinguish between the following pairs :

(a) Monocotyledonous and Dicotyledonous seeds

(b) Epicotyl and Hypocotyl

(c) Epigeal and Hypogeal germination

(d) Radicle and Plumule

(e) Albuminous and Exalbuminous seeds

Answer:

(a) Difference between Monocotyledonous and Dicotyledonous seeds:

Monocotyledonous seed Dicotyledonous seeds
Single cotyledon Two cotyledons
Large endosperm No endosperm or less endosperm
Plumule leaves rolled Plumule leaves folded
Hilum and micropyle not visible. Hilum and micropyle visible.
Fruit wall and seed wall are fused. Seed are present inside the fruit separately.

(b) Difference between Epicotyl and Hypocotyl:

Epicotyl Hypocotyl
The segment of the embryo or axis between the plumule and the cotyledons is known as epicotyl. The segment of the embryo or axis between radical and the cotyledons is called Hypocotyl.
If the epicotyl elongates, the cotyledons remain underground and the germination is then called hypogeal germination. If the hypocotyl elongates, the cotyledons are pushed above the ground and the germination is then called epigeal germination.

(c) Difference between Epigeal and Hypogeal germination:

Epigeal germination Hypogeal germination
Cotyledons are pushed above the ground. Cotyledons remain underground.
Hypocotyl elongates faster. Epicotyl elongates faster.
Usually occurs in dicotyledonous seeds. Usually occurs in monocotyledonous seeds.

(d) Difference between Radicle and Plumule:

Radicle Plumule
Radicle is the part of embryo that gives rise to the root. Plumule is the part of embryo that give rise to the shoot.
Radicle is the first structure to emerge during germination. Plumule remains enclosed within the seed until germination occurs.
Radicle grows downward into the soil and anchors the plant, absorbing water and nutrients from the ground. Plumule emerges from the seed and grows upwards, eventually developing into the stem and leaves of the plant.

(e) Difference between Albuminous and Exalbuminous seeds:

Albuminous seeds Exalbuminous seeds
Cotyledons are thin and membranous. Cotyledons are thick and fleshy.
Endosperm persists. Endosperm does not persist.

 

Question 2.

What are the functions of the following in a seed?

(a) Seed coat

(b) Micropyle

(c) Cotyledons

(d) Radicle

(e) Plumule

Answer:

(a) Seed coat: It protects the delicate inner parts of the seed from injury and the attack of bacteria, fungi and insects.

(b) Micropyle: During germination, micropyle allows water to enter the seed through its pore.

(c) Cotyledons: They contain food for the embryo.

(d) Radicle: It forms the future root.

(e) Plumule: It forms the future shoot.

Question 3.

Suggest an experiment to prove that a suitable temperature is necessary for germination.

Answer:

Aim: To prove that a suitable temperature is necessary for germination.

Apparatus: Two beakers, wet cotton wool, refrigerator

Procedure:

(1) Take two beakers and label them as A and B.

(2) Place some gram seeds on wet cotton wool in each of the beakers.

(3) Keep beaker A at ordinary room temperature and beaker B in the refrigerator.

(4) In 1-2 days, the seeds in beaker A will germinate, showing the importance of a suitable temperature for germination. Seeds in beaker B may not show the signs of germination or may germinate after several days, though not to the extent as the seeds in beaker A.

Inference: Seeds require a suitable temperature for germination.

Question 4.

Sometimes the potatoes kept in a basket during the late rainy season start giving out small shoots. Would you call it germination? Give reason in support of your answer.

Answer:

Yes, we call it germination because all the changes leading to the formation of a seedling collectively constitute germination. During germination, either the epicotyl or the hypocotyl elongates.

(Seeds Structure and Germination Long Answer Class-9 ICSE)

Question 5.

Give two differences in each of the following pairs:

(a) Coleorhiza and coleoptile

(b) Bean seed and maize grain

(c)  Germination and vivipary.

Answer:


(a) differences between Coleorhiza and Coleoptile
Coleorhiza  Coleoptile 
1. Protective sheath of radicle 1. Protective sheath of plumule
2. Present towards the pointed end of embryonic region 2. Present towards the upper broader side of the embryonic region
(b) differences between Bean seed and Maize grain
Bean
seed
Maize
grain
1. Two cotyledons 1. One cotyledon
2. No endosperm 2. Large endosperm present
(c) Differentiate between germination and vivipary.
Germination Vivipary 
When the embryo in the seed becomes activated and begins to grow into a new plant, then it is known as germination. Vivipary is known as the germination of seed within the fruit, while it is still attached to the parent plant.

Question 6.

Justify the statement that the maize grain is a ‘one seeded fruit’.

Answer:

A fruit is the enlarged ripened ovary in which the ovarian wall forms the fruit wall and encloses the seed. The fruit protects the seed and helps in seed dispersal.

The maize grain is regarded as a ‘one-seeded fruit’ because the fruit wall and the seed coat are fused to form a protective layer. Such a fruit is called grain.


D. Long Answer Type

Seeds Structure and Germination Class-9 Biology Concise Solutions  

Page 57

Question 7.

What is the role played by the hypocotyl in epigeal germination?

Answer:

Germination of a seed which takes place above the ground is called epigeal germination. In epigeal germination, the hypocotyl grows forming a loop above the soil. It then straightens pushing the cotyledons above the ground.

Question 8.

Draw a neat and labelled diagram of :

(a) A twig of viviparous plant showing its germination.

(b) A seedling growing in soil.

Answer:

(a) Diagram of a twig of viviparous plant showing its germination:

(a) Diagram of a twig of viviparous plant showing its germination:

(b) Diagram of a seedling growing in soil:

(b) Diagram of a seedling growing in soil:

Question 9.

Draw a neat and labelled diagram of the ‘Experimental set-up of three-bean seed experiment’ and mention the necessity of each condition for the germination of seeds.

Answer:

Experimental set-up of three-bean seed experiment is shown in the diagram below:

Draw a neat and labelled diagram of the 'Experimental set-up of three-bean seed experiment' and mention the necessity of each condition for the germination of seeds.

The observations of the three-bean seed experiment are as follows:

  • The middle seed germinates. It gets both oxygen and water.
  • The bottom seed does not germinate or stops germinating after the emergence of a small radicle. It gets water but very little oxygen (from the air dissolved in water).
  • The top seed does not germinate at all. It gets only oxygen but no water.

Water, suitable temperature and air (oxygen) are necessary for germination.

(a) Water: Water is necessary because:

(i)By absorbing water, the seed swells and consequently the seed coat ruptures allowing the elongating radicle to come out and form the root system.

(ii)Water is essential for chemical reactions and enzyme action on stored food in cotyledons or endosperm, converting it into a diffusable (dissolved) form for the developing embryo.

(b) Suitable temperature: A moderately warm temperature (25°C to 35°C) is usually favourable for germination which is also called optimum temperature. A very low temperature inhibits the growth of the embryo and a very high temperature destroys its delicate tissues.

(c) Oxygen: Oxygen is needed for respiration that provides energy for the rapid cell division and cell growth during germination.

—  : End of Seeds Structure and Germination D. Long Answer Class-9 ICSE Biology Solutions :–

Return to  Return to Concise Selina ICSE Biology Class-9 

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