Question

Hormone involved in breaking dormancy of winter bud is
A.Ethylene
B.Gibberellin
C.Auxin
D.Cytokinin

Answer 1

Hint: Dormancy period is important because it has many roles in the growth and development of the plant. Seed and bud dormancy can be terminated with the help of plant growth regulators. Seed dormancy is a condition in which seed is not able to germinate even if it encounters favorable conditions.

Complete step by step answer:Bud dormancy is an important stage in perennial plants. It is a temporary stage in which metabolic activities slow down in a bud. When favorable conditions are provided, these buds exit dormancy. We commonly use certain plant growth regulators in order to break bud dormancy.
Gibberellins and abscisic acid are the plant growth regulators that are antagonistic in their functions in most situations. Gibberellins break the dormancy of seeds and winter buds. Abscisic acid is the stress hormone and it induces dormancy in seeds and buds.
Other than breaking dormancy and promoting growth, gibberellins perform several functions like delaying senescence of fruits, increasing axis length in grapes, improving the shape and structure of fruits, early seed production, etc.
Other than using plant growth hormones, there are several methods to break the dormancy of seeds. Seed can exit the dormant stage on its own and can start growing. It is also possible to break seed dormancy by certain methods.
The main reason that seed remains dormant is due to the hard impermeable seed coat. We can make the seed coat permeable to water and moisture by breaking the seed coat.
We can also break dormancy by the application of plant growth hormones. By giving exposure to warmth and moisture, we can break dormancy and allow the hard seed coat to break.
Hence the correct option is B.

Note: Know that ethylene is an example for plant growth regulator which is also used for breaking seed and bud dormancy. Note that it is a gaseous regulator and is naturally synthesized in plants in tissues undergoing senescence and ripening fruits. Keep in mind that Abscisic acid helps to induce dormancy.