Gibberellins can promote seed germination because of their influence on

(1) rate of cell division

(2) production of hydrolyzing enzymes

(3) synthesis of abscisic acid

(4) absorption of water through hard seed coat

One hormone hastens maturity period in juvenile conifers, a second hormone controls xylem differentiation, while the third hormone increases the tolerance of plants to various stresses.They are respectively:-

(1) Gibberellin, Auxin, Ethylene

(2) Auxin, Gibberellin, Cytokinin

(3) Gibberellin, Auxin, ABA

(4) Auxin, Gibberellin, ABA

Identify the incorrect statement about ABA growth regulator.

(1) It increases the tolerance of plants against different stresses.

(2) It acts as general plant growth inhibitor and inhibitor of metabolism.

(3) It helps in seed maturation and dormancy.

(4) It promotes morphogenesis and differentiation of shoots.

Which of the following plant growth hormone increase the yield of sugar by increasing the length of stem in sugarcane?
(1) Cytokinin

(2) Ethylene

(3) Gibberellic acid

(4) Auxin

In the process of apical dominance, lateral buds are unable to grow in the presence of apical bud. This is due to:-
(1) less amount of cytokinins in lateral buds

(2) more amount of cytokinins in lateral buds

(3) less amount of auxin in lateral buds

(4) more amount of auxin in lateral buds

Refrigerated fruits maintain flavour and taste for longer period due to:-
(1) non-availability of O₂

(2) the presence of excess of CO₂

(3) the presence of excess humidity

(4) slower rate of respiration

The biological clock measures the length at each night by the?

(1) relative amount of red absorbing and far-red absorbing phytochrome present at dawn

(2) amount of far-red absorbing phytochrome at dusk

(3) relative amount of red absorbing and far-red absorbing phytochrome at mid day

(4) rate at which are kind of phytochrome is converted to the other

A physiological response of plants to the duration of light and darkness is a:-

(1) daily phase cycle

(2) circadian rhythms

(3) biological clock

(4) photoperiodism

ABA is involved in?
(1) shoot elongation   

(2) increased cell division

(3) dormancy of seed 

(4) root elongation

Hypothetical plant hormones are:-
(1) florigen                   

(2) vernalin

(3) florigen and vernalin 

(4) auxin