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

The application of synthetic plant hormone like IAA, IBA and NAA are best described as:-

(1) prevent early fruit fall before harvesting and is used to produce parthenocarpic fruit

(2) prevent early fruit fall only

(3) to produce both seed less fruits and fruits with seeds

(4) to produce larger fruit

Organogenesis or morphogenesis in tissue culture is controlled/regulated by phytohormones the credit of this important discovery goes to

(1) Skoog and Miller (1957)

(2) Guha and Maheswari (1964)

(3) Calvin and Benson (1894)

(4) Halperin and Wetherall (1964)

Which one plant movement is unidirectional?

(1) Phototaxis

(2) Chemotaxis

(3) Both (a) and (b)

(4) Thigmotrophism

Natural cytokinins are synthesized in tissue that are:-

(1) senescent

(2) dividing rapidly

(3) storing food material

(4) differentiating

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

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

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