Page 86 - Biology - XII

Q14. You might have seen potato and sweet potato and eaten it also. Which structure is correct for
potato tuber?
(a) It is oval, circular, and has ‘eyes’ on it. (b) It is spherical and does not have ‘eyes’ on it.
(c) It is under the ground modifi cation of root. (d) I have no idea about it.

Q15. What is the origin/position of thorn and tendril?

(a) Thorn is terminal and tendril is axillary in position.
(b) Thorn and tendril both are axillary in position.
(c) Thorn and tendril both are terminal in position.

(d) I have no idea about it.

Answer key
1. (a), 2. (d), 3. (b), 4. (a), 5. (a), 6. (b), 7. (b), 8. (a), 9. (c), 10. (a), 11. (c), 12. (d), 13. (d),
14. (a), 15. (b)

EXPERIMENT - 16

Objective
To study the reproductive parts of commonly available fl owers.

Principle/Theory
The male reproductive parts of a fl ower are the stamens collectively called androecium and the female
reproductive parts are the carpels/pistils collectively called gynoecium. The individual units of stamen
consist of a fi lament which supports the anther lobes. Gynoecium consists of stigma, style, and ovary.
Many variations are found in diff erent characteristics of both the stamens and carpels. We shall try to study
these variations in the reproductive parts of fl owers in the exercise.

Materials Required
Commonly available fl owers, needles, forceps, razor/scalpel blade, brush, slides, cover slip, watch glass,
magnifying lens, dissecting microscope, compound microscope, etc.

Procedure
1. Observe the fl ower with the naked eye, hand lens, or under a dissecting microscope. Study their
reproductive parts and count the number of stamens and record their cohesive and adhesive features.
2. Cut L.S. of the fl ower and place it on a slide to observe the following characters:
(a) Placement of anthers
(b) Position of the ovary: epigynous/perigynous/hypogynous

3. Mount one stamen on a slide and study the following characters:
(a) Attachment of fi lament to anther
(b) Dehiscence pattern of the anther lobes for discharge of pollen
4. Cut T.S. of anther lobe to observe the number of pollen sacs.

5. Mount the pistil on a slide and study style, stigma, and ovary. Record the number of stigma and nature
of pistil.

85