Question

Name two methods for breaking the seed dormancy.​

Answer 1

Explanation:

Methods of Breaking Seed Dormancy

The different methods of breaking dormancy are mentioned below:

The natural breaking of Seed 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 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. Other natural methods include:

Completion of the over-ripening period.

Leaching of inhibitors present in the seed coat.

Inactivation of inhibitors by the supply of cold, heat, and light.

Leaching of the excess and highly concentrated solutes from the seeds.

Production of growth hormones which can neutralize the effect of inhibitors.

Artificial Overcoming of Seed Dormancy

Some of the artificial methods used for breaking seed dormancy are listed below:

Action with hot water for termination of waxes, surface inhibitors, etc.

Rupturing of seed coats by filing, chipping, or threshing through machines.

Exposure to heat, cold or light, depending upon the type of seed dormancy.

By applying Hydraulic pressure for 5 to 20 minutes in order to weaken the tough seed coats.

Seed coats are treated with concentrated sulphuric acid for removing all traces of the mineral acid.

Answer 2

Answer

Methods for breaking the seed dormancy :

Scarification :

$\bigstar$ Seeds with hard seed coats may remain impermeable to water and oxygen thereby remaining dormant.

$\bigstar$ The seed coat of such seeds is either broken mechanically or by treatment with strong acids like H₂SO₄.

Impaction :

$\bigstar$ The treatment given to seeds when they are shaken vigorously is called Impaction.

Stratification :

$\bigstar$ The practice of layering th seeds during winter in layers of moist sand and peat is called stratification.

Light treatment :

$\bigstar$ Those seeds whose germination is affected by light are said to be photoblastic.

$\bigstar$ If their germination is inhibited, they are called negatively photoblastic. but if they are induced to germinate they are known as positively photoblastic.

Chemicals :

$\bigstar$ There are several chemicals which promote seed germination such as KNO₃, cytokinins, ethylene etc.