1. What is the general name of chemical substances which bring about control and coordination in plants?

2. Which plant hormone is responsible for the wilting and falling of leaves?

3. Which plant hormone makes a stem (or shoot) bend towards light?

4. Where is the auxin hormone made in a plant stem?

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5. What is the scientific name of sensitive plant?

6. Name one plant hormone that promotes growth and another plant hormone which inhibits growth.

7. Name one example of the movement of a plant part which is very quick and can be observed easily.

8. Name the type of chemical substances that control the growth in plants.

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9. What is the stimulus in?

(a) phototropism? (b) geotropism?

(c) chemotropism? (d) hydrotropism? (e) thigmotropism?

10. Give the scientific terms used to represent the following:

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(a) Bending of a shoot towards light.

(b) Growing of roots towards the earth.

(c) Growth of a pollen tube towards ovule.

(d) Bending of roots towards water.

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(e) Winding of tendril around a support.

11. Give one example of the movement of a plant part which is caused by the loss of water (or migration of water).

12. Give one example each of a plant part:

(a) which is positively hydrotropic as well as positively geotropic.

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(b)which is positively phototropic but negatively geotropic.

13. Which of the following is a growth movement and which is not?

(a) folding up of leaves of sensitive plant on touching with hand.

(b)folding up of petals of dandelion flower when light fades.

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14. Name the plant part:

(a) which bends in the direction of gravity but away from light

(b)which bends towards light but away from the force of gravity

15. To which directional stimuli do:

(a) roots respond?

(b)shoots respond?

16. Fill in the following blanks:

(a) A plant’s response to light is called……

(b) A plant’s response to gravity is called……

(c) Plant shoot grows upward in response to….

(d) Plant roots grow downward in response to…..

(e)Tendrils wind around a support in response to…

(f) Plant roots grow towards and in the direction of force of……..

(g) A root of a plant grows downward. This is known as…

(h) ……..is the hormone that causes phototropism in plants

(i) The response of leaves to the sunlight is called……..

Answers:

1. Phytohormones (or Plant hormones) 2. Abscisic acid 3. Auxin 4. In the tip of plant stem, 5. Mimosa pudica 6. Promotes growth : Gibberellin ; Inhibits growth : Abscisic acid 7. Folding up of the leaves of a sensitive plant on touching 8. Plant hormones 11. Folding up of the leaves of a sensitive plant on touching 12. (a) Root (b) Stem (or Shoot) 13. (a) Not a growth movement (b) It is a growth movement 14. (a) Root (b) Stem (or Shoot) 15. (a) Light, Gravity and Water (b) Light and Gravity 16. (a) phototropism (b) geotropism (c) sunlight (d) gravity (e) touch (f) water ; gravity (g) positive geotropism (h) Auxin (i) phototropism