Avena curvature test is a bioassay for examining the activity of

• auxins

• cytokinins

• gibberellins

• ethylene.

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

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.

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

• resins

• lignins

• suberin

• tannins.

'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

The plants respond to photoperiods due to the presence of :

• enzymes

• stomata

• phytochromes

• phytohormones

109.

Which chemical is used for induction of polyploidy?

• Cytokinin

• Nitrous acid

• Colchicine

• IAA

Tendrils exhibit/twining of tendrils is due to

• thigmotropism

• seismonasty

• heliotropism

• diageotropism