Chapter 15 : Plant Growth and Development

How is growth measured in plants?

Write the principal characteristics of PGR’s.

What is apical dominance name the hormone that controls it.

Name any two synthetic auxins. How are they used in agriculture.

What is ‘Bioassay’?

Explain the role played by phytohormone in seed germination.

Mention the names of two such substances that cause seed dormancy?

Would a defoliated plant respond to photoperiodic cycle? Why?

Name the hormone which is responsible for elongation of intermodal regions of
green plants.

i) What do you understand by the tem Development?
ii) Explain the sequence of development process in a plant cell.

Discuss the statement : ‘The growth is measurable’

Differentiate between photoperiodism and vernilisation?

Why is the term short plants a misnomer?

What is bolting? Which hormone is responsible for it?

‘Both growth and differentiation in higher plants are open’ comment.

What is the full form of IAA?

Name the growth regulator which was first isolated from corn kernel and
coconut milk?

What is aleurone layer?

What does the sigmoid growth curve of a population mean?

What are the conditions necessary for growth?

What is heterophylly?

Define vernalization?

What would happen to tissue culture of parenchyma ifa)
Auxin and cytokinin were present in equal quantities.
b) More cytokinin than auxin was present.
c) More auxin than cytokinin was present

Name a non-acidic growth substance.

Which hormone act as “stress hormone”?

What is growth?

What would be expected to happen if:

(a) GA3 is applied to rice seedlings

(b) dividing cells stop differentiating

(c) a rotten fruit gets mixed with unripe fruits

(d) you forget to add cytokinin to the culture medium

Would a defoliated plant respond to photoperiodic cycle? Why?

Which one of the plant growth regulators would you use if you are asked to:

(a) induce rooting in a twig

(b) quickly ripen a fruit

(c) delay leaf senescence

(d) induce growth in axillary buds

(e) ‘bolt’ a rosette plan

t (f) induce immediate stomatal closure in leaves

‘Both a short day plant and a long day plant can produce can flower simultaneously in a given place’. Explain.

‘Both growth and differentiation in higher plants are open’. Comment

Why is abscisic acid also known as stress hormone?

What do you understand by photoperiodism and vernalisation? Describe their significance.

List five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agricultural/horticultural applications of any one of them.

Describe briefly: (a) Arithmetic growth (b) Geometric growth (c) Sigmoid growth curve (d) Absolute and relative growth rates

Why is not any one parameter good enough to demonstrate growth throughout the life of a flowering plant?

Define growth, differentiation, development, dedifferentiation, redifferentiation, determinate growth, meristem and growth rate.