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

Why does shoot of a plant bend towards light?

  1. Due to phototaxis

  2. Due to increase in auxin in its shaded area

  3. Due to presence of cells on the illuminated side

  4. Due to presence of gibberellin

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Shoot of a plant bends towards light due to increase in auxin in the shaded area.

Multiple choice

Which of the following sets contains only cytokinins?

  1. Indole-3-butyric acid, Indole-3-acetic acid, 1-Naphthaleneacetic acid

  2. N6-furfuryladenine, zeatin, benzyl adenine

  3. N6-furfuryladenine, Indole-3-butyric acid, Indole-3-acetic acid

  4. N6-furfuryladenine, zeatin, Indole-3-butyric acid

  5. Zeatin, Indole-3-butyric acid, 1-Naphthaleneacetic acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Kinetin (N6-furfuryladenine) is a type of cytokinin, a class of plant hormone that promotes cell division. Zeatin is a plant hormone derived from the purine adenine. It is a member of the plant growth hormone family known as cytokinins. Benzyl adenine or 6-Benzylaminopurine (BAP) is a first-generation synthetic cytokinin that elicits plant growth and development responses, setting blossoms and stimulating fruit richness by stimulating cell division.

Multiple choice

Polyploidy in plants are introduced using

  1. tryptophan

  2. colchicine

  3. chymosin

  4. gibberellins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 Colchicine is a chemical widely used to double chromosome number and thus introduce polyploidy in plants.

Multiple choice

Astringent makes biological tissue to contract or come closer. Among the following ---------------- is an astringent.

  1. aluminium acetotartrate

  2. aluminium borohydride

  3. aluminium carbide

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

Aluminium acetotartrate (or ALSOL) is an organic acid, astringent, and disinfectant. It is the aluminium salt of acetic acid and tartaric acid. It is employed in 0.5-2% solutions as a nasal douche in affections of the respiratory tract.

Multiple choice

Process of vernalization can be induced by

  1. cytokinin

  2. auxin

  3. phototropin

  4. GA

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

The cooling of seed during germination in order to accelerate flowering when it is planted is called as vernalization. Gibberellic acid controls vernalization.

Multiple choice

Auxin causes

  1. growth of apical bud

  2. growth of lateral bud

  3. seed dormancy

  4. fall of leaf

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Auxin is a plant hormone which causes the elongation of cells in shoots and is involved in regulating plant growth. It also causes growth of apical bud.

Multiple choice

The highest concentration of auxin is found in

  1. root and shoot tips

  2. leaves and fruits

  3. mid stem portion

  4. None of the above

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Depending on the specific tissue, auxin may promote axial elongation (as in shoots), lateral expansion (as in root swelling) or isodiametric expansion (as in fruit growth).

Multiple choice

Ethylene is used for

  1. decreasing senescence

  2. increasing height of stem

  3. ripening of fruits

  4. preventing leaf fall
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethylene is an important natural plant hormone that is used in agriculture to force the ripening of fruits.

Multiple choice

Which of the following is the bioassay of auxin?

  1. Avena geo-curvature test

  2. Callus formation

  3. Culture of fungus

  4. Seed dormancy

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Avena geo-curvature test is a bioassay for auxin-type growth regulators. Much of our current knowledge of auxin was obtained from its applications.

Multiple choice

Leaf abscission is caused by which of the following?

  1. ABA

  2. Gibberellin

  3. Auxin

  4. Cytokinin

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Abscisic acid (ABA) plays a central role in many aspects of plant growth, including seed development, dormancy and germination. It also causes abscission of leaves.