Question

A method of breaking dormancy and allowing ample absorption of water is called
(A) Stratification
(B) Scarification
(C) Vernalization
(D) Devernalization

Answer 1

Hint: Under optimum conditions, the seed coat breaks open to give rise to a young seedling. This process is called germination. Seeds require specific conditions to germinate if those conditions are not met the seed remains dormant. Any part of the seed could sense unsuitable conditions and remain dormant; it could be the seed coat or even the embryo.

Complete answer:
In a controlled environment, the seeds are subjected to various techniques that simulate natural conditions that will initiate the germination of the seeds. This process is called stratification. The stratification technique includes- cold stratification and warm stratification. A sterile medium called the stratifying medium is used. The medium is a mixture of peat sand and vermiculite. It’s mainly used for the cold stratification process. Mainly seeds with embryonic dormancy are subjected to this process.
Scarification involves the use of thermal, mechanical, or chemical means to reverse seed coat dormancy. These methods are employed to weaken or break open the seed coat to initiate germination. Mechanical scarification is the most common method. A knife or sandpaper is rubbed on the seed coat, the coat breaks open and moisture and air enter the seed. The thermal method involves placing the seeds in hot water. The water absorbed aids in the germination.
Vernalization involves subjecting the seeds or plants to low temperatures to initiate germination. Using this method germination can be induced even in warm climates.
Seeds that have undergone vernalization are subjected to very high temperatures to reverse the effects of vernalization. This way the seeds of the plant can again be stored. This process is known as devernalization.

The correct option is (B). A method of breaking dormancy and allowing ample absorption of water is called scarification.

Note: The main factors that affect germination are- water availability, oxygen requirement for metabolic activities, and optimum temperatures. Seed dormancy is classified into two groups- exogenous dormancy and endogenous dormancy. Dormancy caused by factors outside of the embryo is called exogenous dormancy. Seed coat dormancy is an exogenous dormancy. When the embryo is responsible for dormancy it is called endogenous dormancy.