Sometimes seeds of some plant species do not germinate even after obtaining favorable conditions. This condition of a seed is called dormancy. The reason behind this state is that they require a period of rest before being capable of germination. This state may vary from days to years.These conditions are complicated combination of light, water, temperature, gases, seed coats and hormone structures.
The different methods of breaking dormancy are mentioned below:Natural breaking of dormancy – Nature of dormancy stops when the embryo gets appropriate environment such as adaptive moisture and temperature. The seed coat that exists in many species becomes permeable due to due to the rupturing of smoothing action of natural agents like microorganism, temperature, and abrasion by the digestive tract of birds and animals that feed on these seeds.
Treatment to break dormancy – The separate treatments to overcome dormancy can be divided into three groups.
a.Seed coat treatment – These treatments make a hard seed coat permeable to water or gases either by softening or cracking. This process is called as scarification. The treatment can be either chemical or physical in nature.
Stratification: The incubation of seeds at an appropriate low temperature over a moist layer before transferring to a temperature suitable for germination.
High-temperature treatment: Incubation at 40-500C for a few hours to a few days may have an effect in overcoming dormancy in some species. For instance, rice seeds treated in hot water of 400C for at least 4 hours.
Chemical treatments: Growth regulators or other chemicals can be used in induced germination growth regulators.
Dormancy of seeds is for a long time, which acts as a survival mechanism. Seed can adapt to the adverse situations and resist inappropriate germination. But there is no uniform germination. Dormancy makes it difficult to maintain plant population and interferes in seed testing procedure.
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