Multiple Choice Questions

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Ageing is retarded by

  • ABA

  • CKN

  • GA

  • C2H4


B.

CKN

Cytokinins are a class of plant growth substances (phytohormones) that promote cell division or cytokinesis, in plant roots and shoots. They are also involved in cell growth and differentiation but also affect apical dominance, axillary bud growth and leaf senescence.

Eg, degradation of protein and chlorophyll was delayed in the detached leaves of Xanthium, if cytokinin was used in a medium.


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Which of the following is a day neutral plant

  • Helianthus annuus

  • Euphorbia pulcherrima

  • Avena sativa

  • Beta vulgaris


Agricultural chemicals include

  • growth regulators

  • fertilizers

  • pesticides

  • all of these


2,4- D is an effective

  • fungicide

  • weedicide

  • rodenticide

  • wormicide


Pencils are prepared from the wood of

  • Pinus vinaster

  • Juniperus virginiana

  • Chamaecyparis piscifera

  • Abies pindrow


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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.


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.


The dormancy of seed is regulated by

  • ABA

  • Ethylene

  • GA- 3

  • Dihydrozeatin


Which of the following is an antigibberellin

  • Auxin

  • Ethylene

  • ABA

  • Cytokinin


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Auxin in plant means for

  • cell elongation

  • fruit ripening

  • cell division

  • inhibit the root growth


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