What is seed dormancy? State the methods to overcome it.

(N/A) Definition: Seed dormancy is a condition in which seeds fail to germinate even when external conditions (moisture,temperature,oxygen) are favorable for germination.
Explanation: This state is controlled by internal factors rather than external environmental conditions. The seed remains in a resting phase for a specific period.
Factors causing dormancy:
$1$. Impermeable and hard seed coat.
$2$. Presence of chemical inhibitors like $ABA$ (Abscisic Acid).
$3$. Presence of phenolic acids and para-ascorbic acid.
$4$. Immature embryo.
Methods to overcome seed dormancy:
$1$. Mechanical scarification: Rubbing the seed coat with sandpaper or using a knife to make it permeable to water and gases.
$2$. Chemical treatment: Using chemicals like $GA_3$ (Gibberellic acid) or nitrates to neutralize the effect of inhibitors.
$3$. Stratification: Exposing seeds to specific low-temperature conditions to break dormancy.
$4$. Environmental manipulation: Changing light and temperature conditions to trigger germination.
$5$. Natural processes: Microbial action or passage through the digestive tract of animals can also break the seed coat.