Multiple Choice Questions

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

  • resins

  • lignins

  • suberin

  • tannins.


B.

lignins

Cork is impervious to water because it has deposition of suberin. The thin walls of those cells are saturated with fatty waxy substance, called suberin which makes cork almost impervious to water and air.


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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


Which chemical is used for induction of polyploidy?

  • Cytokinin

  • Nitrous acid

  • Colchicine

  • IAA


Ethylene is a

  • gaseous hormone

  • gaseous enzyme

  • liquid-gas mixture

  • solid hormone


Avena curvature test is a bioassay for examining the activity of

  • auxins

  • cytokinins

  • gibberellins

  • ethylene.


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

  • ethylene

  • gibberellin

  • cytokinin

  • indole acetic acid.


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.


Tendrils exhibit/twining of tendrils is due to

  • thigmotropism

  • seismonasty

  • heliotropism

  • diageotropism


The plants respond to photoperiods due to the presence of :

  • enzymes

  • stomata

  • phytochromes

  • phytohormones


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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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