Plant Growth and Development

Auxin was discovered by

• Charles Darwin

• F.W. Went

• Francis Darwin

• F. Skoog

Answer explanation

F.W. Went is credited for discovery of auxin and coined the term as well. C. Darwin and F. Darwin only experimented and found there was something that was responsible for growth on unidirectional illumination of plant stem.

Precursor of Auxin is

• Tryptophan

• Acetyl Co-A

• Zinc

• N-acetyl glcosamine

Select the odd one out with respect to Auxin

• Naphthalene Acetic Acid

• 2,4-Dichloro phenoxy acid

• Indole Propionic Acid

• Indole Butyric Acid

Answer explanation

NAA, 2,4-D and IPA are synthetic auxins whereas IBA is a natural auxin.

Decapitation is done in tea plantation to promote lateral growth. This fact is related to:

• Gibberallin

• Auxin

• Cytokinin

• Ethylene

Answer explanation

Apical Dominance, i.e. apex grows first due to higher concentration of auxin produced by shoot apex. But if decapitation occurs, the concentration of auxin falls which is suitable for lateral growth.

Shoot initiation is promoted mainly by-

• Auxin

• Cytokinin

• Gibberallin

• Ethylene

Callus is-

• Ethylene derivative

• Auxin derivative

• Gibberellin derivative

• None of these

Answer explanation

Callus is mass of undifferentiated cells in culture medium.

Which of the following can be used in plant propagation to promote root growth-

• Auxin

• Cytokinin

• Gibberellin

• Ethylene

Which of the following promotes senescence mainly?

• Auxin

• Cytokinin

• Gibberellin

• ABA

Abscission is promoted mainly by-

• Auxin

• Cytokinin

• Giberellin

• ABA

Simultaneous leaf senescence is found in-

• Annuals

• Biennials

• Perennials

• Evergreen plants