NCERT Class 11 Biology Plant Growth and Development

PLANT GROWTH AND DEVELOPMENT

VERY SHORT ANSWER TYPE QUESTIONS

1. Fill in the places with appropriate word/ words.

a. A phase of growth which is maximum and fastest is __________.

b. Apical dominance as expressed in dicotyledonous plants is due to the presence of more ________ in the apical bud than in the lateral ones 

c. In addition to auxin, a ________ must be supplied to culture medium to obtain a good callus in plant tissue culture.

d. ________ of a vegetative plants are the sites of photoperiodic perception.

2. Plant growth substances (PGS) have innumerable practical applications. Name the PGS you should use to

a. Increase yield of sugar cane.

b. Promote lateral shoot growth.

c. Cause sprouting of potato tuber.

d. Inhibit seed germination.

3. A primary root grows from 5 cm to 19 cm in a week. Calculate the growth rate and relative growth rate over the period.

4. Gibberellins were first discovered in Japan when rice plants were suffering from bakane (the foolish seedling disease) caused by a fungus Gibberella fujikuroi.

a. Give two functions of this phytohormone.

b. Which property of Gibberellin caused foolish seedling disease in rice?

5. Gibberellins promote the formation of ______ flowers on genetically _____ plants in Cannabis whereas ethylene promotes formation of _______ flowers on genetically ______ plants.

6. Classify the following plants into Long-Day Plants (LDP), Short Day Plants (SDP) and Day Neutral Plants (DNP) Xanthium, Henbane (Hyoscyamus niger), Spinach, Rice, Strawberry, Bryophyllum, Sunflower, Tomato, Maize.

7. A farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant growth regulator can be applied to achieve this?

8. Where are the following hormones synthesized in plants

a. IAA

b. Gibberellins

c. Cytokinins

9. In botanical gardens and tea gardens, gardeners trim the plants regularly so that they remain bushy. Does this practice have any scientific explanation?

10. Light plays an important role in the life of all organism. Name any three physiological processes in plants which are affected by light.

11. In the figure of Sigmoid growth curve given below, label segments 1, 2 and 3.

12.Growth is one of the characteristic of all living organism? Do unicellular organism also grow? If so, what are the parameters?

13. The rice seedlings infected with fungus Gibberlla fujikuroi is called foolish seedlings? What was the reason behind it?

SHORT ANSWER TYPE QUESTIONS

1. Nicotiana tabacum, a Short Day Plant, when exposed to more than critical period of light fails to flower. Explain.

2. What are the structural characteristics of

a. Meristematic cells near root tip

b. The cells in the elongation zone of the root

3. Does the growth pattern in plants differ from that in animals? Do all the parts of plant grow indefinitely? If not, name the regions of plant, which can grow indefinitely.

4. Explain in 2-3 lines each of the following terms with the help of examples taken from different plant tissues

a. Differentiation

b. De-differentiation

c. Redifferentiation

5. Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth, flowering and rooting. Write a line to explain the meaning of the following terms related to auxins.

a. auxin precursors

b. anti-auxins

c. synthetic auxins

6. The role of ethylene and abscissic acid is both positive and negative. Justify the statement.

7. While experimentation, why do you think it is difficult to assign any affect seen to any single hormone?

8. What is the mechanism underlying the phenomenon by which the terminal/apical bud suppresses the growth of lateral buds? Suggest measures to overcome this phenomenon.

9. In animals there are special glands secreting hormones, whereas there are no glands in plants. Where are plant hormones formed? How are the hormones translocated to the site of activity?

10. Many discoveries in science have been accidental. This is true for plant hormones also. Can you justify this statement by giving an example? Also what term is used for such accidental findings?

Please refer to attached file for NCERT Class 11 Biology Plant Growth and Development