Biology

Plant Growth and Hormones

695 Questions

Plant growth and hormones is a vital topic in biology that covers the physiological effects of different plant regulators like auxins, gibberellins, and cytokinins. These concepts are frequently tested in various general science sections of competitive exams. Practicing these questions helps clarify complex mechanisms like vernalisation, senescence, and tropism for test takers.

Abscisic acid effectsCytokinin functionsAuxins and tropismPlant tissue cultureSenescence in plantsNatural plant hormones

Plant Growth and Hormones Questions

Multiple choice

Which of the following is not a plant hormone?

  1. Abscisic acid

  2. Cytokinin

  3. Auxin

  4. Ascorbic acid

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct option as ascorbic acid is not a plant hormone. Ascorbic acid is a naturally occurring organic compound with antioxidant properties.

Multiple choice

Match the following:

 
a. Auxins 1. It promotes the dormancy in seeds and buds as well as promotes the closing of stomata.
b. Gibberellins 2. It is the plant hormones that promote cell enlargement and cell differentiation in plants.
c. Abscisic acid 3. It help in breaking the dormancy in seeds and buds and is also involved in shoot extensions.

  1. a - 2, b - 3, c - 1

  2. a - 2, b - 1, c - 3

  3. a - 3, b - 2, c - 1

  4. a - 1, b - 2, c - 3

  5. a - 1, b - 3, c - 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option. Auxins are the plant hormones that promote cell enlargement and cell differentiation in plants. Gibberellins help in breaking dormancy in seeds and buds, and are also involved in shoot extensions. Abscisic acid promotes dormancy in seeds and buds as well as promotes the closing of stomata.

Multiple choice

In unisexual plants, sex can be changed by application of

  1. Auxins (or Ethylene)

  2. ABA

  3. Ethanol

  4. Cytokinins
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In unisexual plants, sex expression can be modified by applying plant growth regulators, particularly auxins and ethylene. These hormones can influence the development of male or female flowers. For example, applying auxins or ethylene often promotes femaleness in certain species, while gibberellins may promote maleness.

Multiple choice

Which of the following is not a hormone?

  1. GA3

  2. Ethylene

  3. Phytochrome

  4. Auxins
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phytochrome is a pigment found in plants that acts as a photoreceptor, not a hormone. GA3 (gibberellin), ethylene, and auxins are all well-known plant hormones.

Multiple choice

Movement of auxin is

  1. centripetal

  2. basipetal

  3. acropetal

  4. both 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Auxin transport in plants is polar, specifically moving from the shoot tip downwards toward the roots, which is known as basipetal transport.

Multiple choice

The substance which induces shoot in callus is called __________.

  1. kinetin

  2. GABA

  3. auxin

  4. ABA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Kinetin is part of a group of similar plant hormones, called cytokinins. Its primary role is to extend plant life by promoting cell division and cell enlargement. It is also involved in apical dominance. Kinetin is also called 6-Furfurylaminopurine.