Breaking Seed Dormancy for Better and Enhanced Germination
|Major subject||Plant physiology|
What is dormancy?
Dormancy is the hindered development and reversible rest period of plant organs either of a seed or any vegetative part.
What is seed dormancy?
Seed dormancy is a biological condition where a seed is fail to germinate due to unfavourable circumstances, eg., winter period or hot summer. Some seeds like seeds of Solanum torvum are unable to germinate during summer season without chemical treatment. During this period, there is very poor or total suspension of respiration or rather anaerobic respiration with higher respiration quoteint.
Ranil et al. (2015) found that treatments with GA3 and KNO3, among others, such as immersion in water for 24 h and light irradiation, have highly positive effects on Solanum torvum seed germination.
Cause of dormancy in seeds
The formation of dormant structure is a commonly associated cause with the suspension of metabolic, synthetic and morphogenetic activities that are associated with the minimum physiological and minimum moisture content.
The inactivity of hydrolytic enzymes is the cause of dormancy.
Role of plant hormones
Gibberellin(s): It is the predominant germination agent. Gibberellins are present in the germination phase during the food reserve degradation stage.
Cytokinin(s): Cytokinin shows its influence later on the initiation of cell proliferation and expansion.
Role of light
- Red light: 660 mu red light promotes seed
- Blue: Blue specially far-red light (735 mu) inhibits seed germination.
How to break the dormancy of seeds?
Methods of breaking seed dormancy
- Physical treatment
- Chemical treatment
- High temperature treatment: Temperature should be 40-45°C. The duration of heat treatments should be different.
- Low temperature treatment: Soak the seeds in water for 36 hours. Now keep it in 2-8°C for 12-24 hours.
- Alternate heating: Follow alternate heating and cooling for several times.
- Drying and wetting: Follow alternate drying and wetting practice for several times.
- Red light treatment: Soak the seeds in water for 24 hours. Expose the seeds to red light for 1-2 hours at 15-25°C.
- Seed scarification: Dehusk or remove seed coat by rubbing. This practice will make it permeable to water.
- Inorganic chemicals
- Organic chemicals
01: Inorganic chemicals
- Acid treatment: Dilute solutions of HNO3, HCL or H2SO4 (0.1-0.5%) for different durations in minutes.
- Potassium nitrate (KNO3, 1-3%): It is the strongest chemical. You can use it for immediate dormancy break after harvesting. NH4NO3 (1-3%). H2O2, H3BO4 etc.
- Use of gases: By increasing O2 concentration.
02: Organic chemicals
- Non hormonal: Thiourea and ascorbic acid are examples of non hormonal organic chemicals.
- Hormonal: GA3 (1-1000 ppm). Gibberellic acid ot GA3 is a very common seed dormancy breaker. It is very easy to use.
- Other chemicals: Kinetin (1-100 ppm), Ethylene (ethrel solution of 100-300 ppm).
Methods of checking seed germination
- Dehumidification: Removal of water-vapour from the air in storage. Silica gel is the most common desiccant.
- Tempering: Process of bringing grains or other products to desired moisture or temperature for processing.
Frequently asked questions
Where can I get these chemicals?
You can get it at any agricultural shop. Always buy it from a genuine store.
Which is the best chemical to break seed dormancy?
GA3 is the most common and the best chemical to break seed dormancy.
Which is easily available?
GA3 or Gibberellic Acid is easily available PGR.
Can you send me GA3?
Yes. For this go to contact. Make us a call and place your order.
PPM: It stands for Part Per Million
RANIL, R. H. G. et al. Improving seed germination of the eggplant rootstock Solanum torvum by testing multiple factors using an orthogonal array design. Scientia Horticulturae, v. 193, n. 9, p. 174-181, 2015.