Multiple Choice Questions

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

  • ethylene

  • gibberellin

  • cytokinin

  • indole acetic acid.


D.

indole acetic acid.

“It has been known since the 1930s that the plant hormone auxin is released by the plant’s actively growing tip and is transported down the main stem where it has an indirect effect on buds to inhibit branching. There are a number of ways in which the hormone exerts this effect and we have discovered a new path by which it works.”

The research suggests that for a shoot tip to be active, it must be able to export auxin into the main stem. But if substantial amounts of auxin already exist in the main stem, export from an additional shoot tip cannot be established


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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


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.


The plants respond to photoperiods due to the presence of :

  • enzymes

  • stomata

  • phytochromes

  • phytohormones


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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


Ethylene is a

  • gaseous hormone

  • gaseous enzyme

  • liquid-gas mixture

  • solid hormone


Which chemical is used for induction of polyploidy?

  • Cytokinin

  • Nitrous acid

  • Colchicine

  • IAA


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.


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Tendrils exhibit/twining of tendrils is due to

  • thigmotropism

  • seismonasty

  • heliotropism

  • diageotropism


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