FRANK Solutions for Class 9 Biology Chapter 9 - Seeds: Structure and Germination
Enjoy non-stop access to Frank Solutions for ICSE Class 9 Biology Chapter 9 Seeds: Structure and Germination at TopperLearning. Understand chapter-related terms such as epigeal germination, dormancy, coleoptile. Get complete answers to all MCQs and short answers questions for a quick revision.
This ICSE Class 9 Biology chapter also covers the three beans experiment. Revise the answers given by our experts to learn about the important concepts related to germination and structure of a seed. To boost your exam score, explore our video lessons, mock exam question papers and more.
Chapter 9 - Seeds: Structure and Germination Exercise 78
(b) The process by which the dormant embryo of the seed resumes active growth and forms a seedling is known as germination.
food is stored mainly in the endosperm. Such seeds are called albuminous seeds. Example - Seeds of castor, cereals and grasses.
(b) Dormancy - Seed dormancy is a condition of plant seeds that prevents germination under optimal environmental conditions. Here the seed is in a state of apparent inactivity and will not grow even if favorable conditions are provided, until a definite time has elapsed.
(c) Hypogeal germination - In this germination, the seed remains inside the soil since epicotyl elongates faster than hypocotyl. Hence the cotyledons remain inside the soil. Example - Wheat, rice, pea, mango.
(d) Epigeal germination - It is a type of germination in which cotyledons are pushed above the soil into the air and light. This occurs due to rapid growth and elongation of the hypocotyl. Example - Bean, cotton, castor, papaya, onion, tamarind.
(b) Micropyle allows entry of water into the embryo.
(c) Endosperm contains stored food mostly as starch.
(d) Cotyledons store food material for the embryo.
(e) Root and shoot
(g) Epigeal germination
(h) Hypogeal germination
(i) Orchis seed
(j) Seed of Lodoicea moldivica
Chapter 9 - Seeds: Structure and Germination Exercise 79
(b) grasses, wheat
(c) pea, mango
(d) wheat, rice
(i) Water - Water is essential for seed germination since protoplasm becomes active only when saturated with water. Water facilitates the necessary chemical changes in food material. Also enzymatic reaction occurs only in the water medium. Water when imbibed by the seed coat makes it soft and swollen. Then the seed coat bursts open, helping the embryo come out easily.
(ii) Temperature - A suitable temperature is essential for seed germination since many physiological processes occur within the seed during germination. Seeds fail to germinate below 0?C or above 45?C. Optimum temperature for seed germination is 15-30?C.
(iii) Oxygen - During germination, embryo resumes growth and for this energy is required. This energy comes from the oxidation of food material stored in the endosperm or cotyledons. This process requires oxygen.
The air-dried seeds are attached to a piece of wood, one at each end and one in the middle. This is then placed in a beaker and water is poured into it till the middle seed is half immersed in it. The beaker is then left in a warm place for a couple of days. From time to time, water is added to maintain the original level.
It is observed that after a couple of days that the bean in the middle germinates normally since it has sufficient water, oxygen and temperature. The bottom seed gets sufficient water and temperature but not oxygen hence it may develop a radicle but doesn't grow further. The upper seed gets oxygen and temperature but not water and hence fails to germinate.
This experiment shows that water, temperature and oxygen are essential for seed germination and that germination will not occur if any one of these factors are absent.
(ii) (d) castor bean
(iii) (d) all the above
(iv) (d) maize
(v) (a) double coconut
(vi) (b) germination
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number