BIO XI 4.5

BIO XI 4.5

CHAPTER15. PLANT GROWTH & DEVELOPMENT

 KEY TERMS:

Growth, differentiation, growth regulators, sigmoid growth curve, auxins, Gibberellins, cytokinins, ethylene, abscisic acid, abscission, photoperiodism, phytochrome, vernalisation, rosette, bolting, senescence, dormancy quiescence, 

BIO XI 4.5.1

Q.1. Define the following terms:

(a)growth

(b) differentiation

(c) development

(d) redifferentiation

(e) dedifferentiation

Q.2. Name the three  phases of growth?

Q.3. Write any three differences between arithmetic growth and geometric growth.

Q.4. Write equations for arithmetic growth and geometric growth.

Q.5. Draw a graph to show sigmoid growth curve and label the three phases of this curve.

Q.6. Define development. What are intrinsic and extrinsic factors which determine the growth of a plant? 

BIO XI 4.5.2

Q.7. Name scientists who discovered the following

 (a).auxins (b) gibberellins (c) cytokinins (d) ethylene (e)abscisic acid

Q.8. Name the following plant hormones:

(a) Root Promoting hormone.

(b) Stem elongating hormone

(c) Tumour  or gall forming hormone

(d) Fruit ripening hormone/ gaseous hormone

(e) Stress hormone

(f) Hormone causing apical dominance

(g) Hormone causing bolting in rosette plants.

(h) Hormone speeding up malting on breweries.

(i) Delay senescence

(j) Induce parthenocarpy

(k) Closing of stomata

Q.9. Briefly describe the natural and/or synthetic forms, physiological effects, and agricultural uses of each one of the following:

 (a).auxins (b) gibberellins (c) cytokinins (d) ethylene (e)abscisic acid

Q.10. What is meant by photoperiodism ?what are long day plants, short day plants, day neutral plants? Give two examples of each type.

Q.11. Name the chemical which is responsible for photoperiodism in plant.

Q.12. What is vernalisation?

BIO XI 4.5.3

Q.13. Describe briefly (a) arithmetic growth (b) geometric growth (c) sigmoid growth curve

Q.14. Name the fungus from which gibberellins were extracted.

Q.15. Who discovered auxins, gibberellins, cytokinins and ethylene?

Q.16. Why ABA is termed dormin or stress hormone.

Q.17. ABA is a growth retardant still it is useful for plant. How?

 COMPETITION POINT:

1. Write precursor molecules, site of synthesis and bioassay of following plant hormones:

  (a).auxins (b) gibberellins (c) cytokinins (d) ethylene (e)abscisic acid

2. Differentiate between seed dormancy and quiescence.

3. What causes seed dormancy in plants?  How it can be overcome?

4. Which mineral ion is necessary for auxin synthesis?

5. What are climacteric fruits? Give examples.