Physiological dormancy inhibits embryo growth and seed germination until chemical changes take place. It is an endogenous dormancy.

Secondary dormancy occurs in some non-dormant and post dormant seeds that are exposed to conditions that are not favorable for germination, like high temperatures. It is caused by conditions that occur after the seed has been dispersed.

This plant hormone restricts shoot branching in the plant.

In certain angiospermic herbaceous perennials, like banana and gladiolus, above the ground part of the shoot dies each year after flowering and fruiting, but the underground parts (stem and roots) survive and put out new shoots the next year.

This particular movement is observed in twiners and climbers. This results in curvature and helps in twinning around the support.

The delay of senescence of leaves and other organs of the plants by cytokinins is called Richmond Lang effect.

Morphactins include several synthetic fluorine-containing compounds that tend to produce morphological changes and suppress the growth in plants.

Auxin is synthesised in apical meristems of shoots. 

 Gibberellic acid was first isolated from Giberella fujikuroii.

The correct answer is option 2.

 The correct answer is  Impatiens.

 The phenomenon of responding to an external stimulus like light is known as phototropism.

  90 gibberellins have been isolated so far.

 Increase in length of a plant can be measured by an instrument called auxanometer.

Ethylene is widely used in the ripening of fruits.