Question

Mechanical injury of seed cost to break dormancy is called
A) Scarification
B) Stratification
C) Impaction
D) Compaction

Answer 1

Hint:Seed dormancy is one of the methodology applied by seeds in order to protect plants from the adverse external conditions as they undergo dormant stage or resting stage until and unless a suitable environmental change is sensed.

Complete answer:
Seed dormancy is one of the evolutionary adaptations developed by seeds. One there is a suitable environment there must be a process which helps in breaking dormancy stage and become active. This can happen naturally by leaching and other processes and can be done artificially by following scarification, stratification, impaction and compaction.

Stratification is a process where the seeds are exposed to cold and moist conditions which makes oxygen available to it before germination of seeds begin, thus helps in breaking dormancy in seeds. Impaction is once off the artificial methodology of breaking seed coast by shaking the seeds and by altering the temperature from low to light or vice Vera.

Impaction also included changing of artificial external conditions such as light, temperature, humidity, pressure which lead to the germination of seeds and exit dormancy. Compaction is also one of the artificial methods to exit dormancy of seeds where the soil conditions are changed in order for the nutrients to initiate germination. Scarification is one of the processes which involves mechanical injury of seed coat and thus stimulates germination.

Hence the correct answer is option A.

Note:Above given forms are artificial methods to exit dormancy, natural methods for the same includes, leaching, action of microbes, completion of over ripening period, attaining maturity of embryo and finally by growth hormone.