Seeds of some plants germinate immediately after shedding from the plants,while in other plants,they require a period of rest before germination. The latter phenomenon is called dormancy. Give the reasons for seed dormancy and some methods to break it.

(N/A) $\rightarrow$ Dormant seeds do not germinate for a specific period. This duration can range from days to months,and this specific time is called the $\text{Dormancy period}$.
$\rightarrow$ Reasons for $\text{Dormancy}$:
$(a)$ $\text{Impermeable seed coat}$: In many plants,the seed coat is impermeable to water (e.g.,$\text{Chenopodium}$,$\text{Trigonella}$,$\text{Melilotus}$),oxygen (e.g.,$\text{Brassica alba}$,$\text{Pyrus malus}$),or chemicals (e.g.,$\text{Xanthium}$).
$(b)$ $\text{Mechanical inhibition}$: In some plants,the seed coat is very hard,providing mechanical resistance to embryo development (e.g.,$\text{Capsella}$,$\text{Lepidium}$).
$(c)$ $\text{Chemical inhibitors}$: Some seeds produce inhibitors like $\text{Abscisic acid (ABA)}$,phenolic acids,coumarin,or short-chained fatty acids that obstruct germination. These can be present in the fruit (e.g.,$\text{Ferulic acid}$ in tomato juice),endosperm (e.g.,$\text{Xanthium}$),or seed coat (e.g.,$\text{Cucurbita}$).
$(d)$ $\text{Immature embryo}$: Seeds like wheat,barley,and oats require a period of rest to mature and develop the ability to germinate. During this time,they synthesize necessary hormones.
$\rightarrow$ Methods to break $\text{Dormancy}$:
$(1)$ $\text{Temperature treatment}$: Exposure to specific heat or cold to deactivate growth inhibitors.
$(2)$ $\text{Scarification}$: Weakening the hard or impermeable seed coat through mechanical abrasion.
$(3)$ $\text{Biological action}$: Microorganisms in the soil decompose and weaken the hard seed coat.
$(4)$ $\text{Leaching}$: Removing inhibitors using rain or irrigation water.
$(5)$ $\text{After-ripening}$: Allowing time for the embryo to reach maturity.