Biology : Plant Growth and Development

Which of the following is a day neutral plant

• Helianthus annuus

• Euphorbia pulcherrima

• Avena sativa

• Beta vulgaris

Which of the following is an antigibberellin

• Auxin

• Ethylene

• ABA

• Cytokinin

Identify the incorrect statement about ABA growth regulator

• It increases the tolerance of plants against different stresses.

• It acts as general plant growth inhibitor and inhibitor of metabolism.

• It helps in seed maturation and dormancy.

• It promotes morphogenesis and differentiation of shoots.

2,4- D is an effective

• fungicide

• weedicide

• rodenticide

• wormicide

Assertion: Secondary metabolites are produced in small quantities and their extraction from the plant is difficult and expensive.

Reason: Secondary metabolites can be commercially produced by using tissue culture technique.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Yeasts are unicellular fungi that are used in bakery and brewery industries.

Reason: Potato spindle tuber disease is caused by viroids

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

One hormone hastens maturity period in juvenile conifers, a second hormone controls xylem differentiation, while the third hormone increases the tolerance of plants to various stresses. They are respectively

• Gibberellin, Auxin, Ethylene

• Auxin, Gibberellin, Cytokinin

• Gibberellin, Auxin, ABA

• Auxin, Gibberellin, ABA

Gibberellins can promote seed germination because of their influence on

• rate of cell division

• production of hydrolysing enzymes

• synthesis of abscisic acid

• absorption of water through hard seed coat.

Assertion: Plant growth regulators (PGRs) are very important for plant growth and development.

Reason: Auxins do not induce flowering in gymnosperms

• If both assertion and reason are true and reason is the correct explanation of assertion. 

• If both assertion and reason are true but reason is not the correct explanation of assertion. 

• If assertion is true but reason is false. 

• If both assertion and reason are false.

Assertion: A correct concentration of auxin and cytokinin is required for the development of root and shoot in a callus.

Reason: When the ratio of kinetin to auxin is high, then only shoots develop. But when the ratio is low then only roots develop.

• If both assertion and reason are true and reason is the correct explanation of assertion. 

• If both assertion and reason are true but reason is not the correct explanation of assertion. 

• If assertion is true but reason is false. 

• If both assertion and reason are false.