Biology

Plant Growth and Hormones

727 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 sentences are in accordance with direct inhibition hypothesis?

  1. Auxins from axillary buds travel up to apical buds to stimulate bud growth.

  2. Cytokinins move from roots to shoot signalling lateral bud growth.

  3. Cytokinins move from shoot to root to induce root morphogenesis.

  4. Auxin from apical buds travel down shoots to stimulate auxiliary bud growth.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is true. Cytokinin moves from the roots into the shoots, eventually signalling lateral bud growth.

Multiple choice

What is the primary action of brassinosteroids?

  1. Control agents for pollen leaf incompatibility

  2. Seed germination inducers

  3. Plant defence substances

  4. Plant strengthening substances
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Brassinosteroids are a class of polyhydroxysteroids, a group of plant growth regulators. 

Multiple choice

Which of the following is not an effect produced by abscisic acid in plants?

  1. Inhibition of fruit ripening

  2. Inhibition of synthesis of kinetin nucleotide

  3. Inhibition of short day induced flower initiation in Pharbitus nil

  4. Action on endodermis to prevent growth of roots when exposed to salty conditions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Abscisic acid does not inhibit short day induced flower initiation in Pharbitus nil.

Multiple choice

Pyrabactin (a pyridyl-containing ABA activator) is a naphthalene sulphonamide hypocotyl cell expansion inhibitor. Which of the following sentences are true with respect to pyrabactin?

  1. It is very sensitive to light.

  2. It is a naturally produced stress hormone.

  3. It is an antagonist of ABA.

  4. It is an agonist of the seed ABA signalling pathway.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is true. Pyrabactin is an agonist of the seed ABA signalling pathway.

Multiple choice

Auxanometer is used to detect :

  1. respiration

  2. transpiration

  3. plant movement

  4. growth

  5. excretion
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An auxanometer is an apparatus for measuring increase or rate of growth in plants.