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What are the artificial methods of breaking the seed dormancy?

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Some of the artificial methods of breaking the seed dormancy are:

  1. Scarification: The process of removing or mechanically disrupting the seed coat so as to accelerate seed germination is called as the scarification. In the laboratories the scarification is done with the help of files or sandpaper or soaking in the concentrated sulphuric acid for some times. It process of scarification also occurs naturally by abrasion by sand, microbial action or when the seed passes through the animal gut (acidic condition in the gut). The seed dormancy as a result of resistant or impermeable seed coat can be overcome by scarification.
  2. Low temperature or Stratification: Seed stratification is the technique used to break dormancy. The seeds are treated in moist medium at low temperature for a period of time. It is a special treatment to overcome the internal dormancy. Stratification involves the cold and warm stratification. The double dormancy is overcome by doing the seed stratification after the seed scarification process. The cold treatment destroys the inhibitors present in the seed coat.
  3. Alternating temperatures: The seeds are usually incubated at low temperature these seeds require a specific temperature for germination. The difference between the two temperatures should not be more than 10°C or 20°C. Hot water treatments is also a method to break the seed dormancy.
  4. Hormone treatment and chemicals: Application of low level growth regulators like gibberellins, cytokinins and ethylene, chlorohydrins etc. will help to break seed dormancy. Some chemicals such sulphuric acid, potassium nitrate, ethylene, chlorohydrine and thiourea are widely used for breaking seed dormancy.
  5. Pressure: The germination of certain seeds can be improved when the seeds are subjected to hydraulic pressure of 2000 atm. At 18°C for 5-20 minutes.
  6. Light: In certain varieties of seeds the germination does not occurs in the darkness. But when the seeds are exposed to sun light the germination occurs very quickly. Such seeds are called as the light sensitive seeds. It also acts an important factor that triggers the germination process. The dormancy due to the positively photoblastic seeds can be broken by exposing them to red light.