Question

By which of the following method or methods seed dormancy can be broken or its duration can be reduced?
A. Scratching of seed coat
B. Layering of seeds
C. Change in the light, pressure and temperature
D. All of the above

Answer 1

Hint: Seed dormancy is an adaptation that stops seeds from germinating during unfavourable ecological conditions. Dormant seeds are the seeds which fail to germinate. This can be overcome by several artificial methods.

Complete step by step answer: Seed dormancy can be broken by several methods;
Artificial methods for breaking the seed dormancy consistS of several methods as mentioned below:
a. Scarification - It is the weakening of seed coats by a mechanical scrape. Sometimes for weakening seed coats, chemical treatments are given. Mechanically, vigorous shaking breaks the dormancy. Chemically, the seeds are treated with chemicals like ethylene, thiourea, potassium nitrate it makes the seed coats soft and weak.
b. Seed layering is an important technique to reduce seed dormancy.
c. Chilling treatment - The dormancy can be broken by chilling treatments, just above freezing point.
d. Alternating temperatures - Seeds are exposed to irregular high and low temperatures to reduce the effect of the inhibitory substances.
e. Running water treatment - Running water can wash off the inhibitors from the seeds and breaks dormancy.
f. Soaking in water - Before sowing, seeds are soaked in water overnight, as a result of which, It softens the outer seed coat. The phenomenon of imbibition helps to break seed dormancy.
So, the correct answer is option D.

Note: Plant hormones are also used to break dormancy. Examples are gibberellin and cytokinin.
Dormancy can be a physical dormancy or a morphological dormancy. In some plants, dormancy can be broken by exposing them to bright light.