Multiple Choice Questions

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Which chemical is used for induction of polyploidy?

  • Cytokinin

  • Nitrous acid

  • Colchicine

  • IAA


C.

Colchicine

Colchicine is an alkaloid obtained from the plant. Colchicum autumnale and is found to prevent the formation and organization of spindle fibres. It induces polyploidy in many plant and animal cells.


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Ethylene is a

  • gaseous hormone

  • gaseous enzyme

  • liquid-gas mixture

  • solid hormone


The plants respond to photoperiods due to the presence of :

  • enzymes

  • stomata

  • phytochromes

  • phytohormones


Cork cambium results in the formation of cork which becomes impermeable to water due to the accumulation of

  • resins

  • lignins

  • suberin

  • tannins.


Avena curvature test is a bioassay for examining the activity of

  • auxins

  • cytokinins

  • gibberellins

  • ethylene.


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In a plant organ which is covered by periderm and in which the stomata are absent, some gaseous exchange still takes place through

  • aerenchyma

  • trichornes

  • pneumatophores

  • lenticels.


Pruning of plants promotes branching because the axillary buds get sensitized to

  • ethylene

  • gibberellin

  • cytokinin

  • indole acetic acid.


Tendrils exhibit/twining of tendrils is due to

  • thigmotropism

  • seismonasty

  • heliotropism

  • diageotropism


Gibberellins can promote seed germination because of their influence on

  • rate of cell division

  • production of hydrolyzing enzymes

  • synthesis of abscisic acid

  • absorption of water through hard seed coat


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'Climacteric' is

  • a phenomenon related to fruit ripening

  • the condition of a plant when all its fruits are almost ripe

  • the condition of a plant when most of its leaves have turned yellow

  • none of the above


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