What is seed dormancy discuss its types and control measures?
Seed dormancy can be defined as the state or a condition in which seeds are prevented from germinating even under the favourable environmental conditions for germination including, temperature, water, light, gas, seed coats, and other mechanical restrictions.
Is seed germination controlled by hormone signaling?
Seed germination is regulated by endogenous hormonal cues and external environmental signals such as water, low temperature and light, which influence whether an imbibed seed completes germination or remains dormant (reviewed in refs.
How is seed dormancy regulated?
Induction and release of seed dormancy is mainly under the control of abscisic acid (ABA) and gibberellic acid (GA). ABA promotes seed dormancy and germination inhibition. Action of ABA is counteracted by GA, which promotes seed germination at appropriate time.
What are the two types of seed dormancy?
There are two different categories of seed dormancy: exogenous and endogenous (Scarification). Exogenous dormancy is caused by conditions outside of the seed’s embryo. An example of exogenous dormancy is when the seed coat is too durable for moisture to infiltrate, effectively preventing germination.
What is dormancy and its types?
There are two types of seed dormancy in general: seed coat (physical) dormancy and internal dormancy. In seed coat dormancy, the seed coat prevents oxygen and/or water permeating into the seed. Sometimes, dormancy is caused by inhibiting chemicals inside the seed.
Which growth hormone is responsible for breaking of seed dormancy?
Gibberellins
Gibberellins break the dormancy of seeds and winter buds. Abscisic acid is the stress hormone and it induces dormancy in seeds and buds.
What are the disadvantages of seed dormancy?
There are many disadvantages to seed dormancy. Dormancy prevents prompt and uniform emergence of seedlings; interferes with planting schedules; contributes to “volunteering” of crops; and causes problems to the seed analyst.
How do you overcome seed dormancy?
Treatments to Overcome Seed Dormancy
- Mechanical Scarification.
- Hot Water Scarification.
- Drop into hot water (77 to 100oC), remove from heat, allow to cool and soak for 24 hours.
- Acid Scarification.
- Seeds, in small batches, are brought into contact with 93% Technical Grade sulphuric acid.
- Warm Moist Scarification.
What is the importance of seed dormancy?
Seed dormancy allows seeds to overcome periods that are unfavourable for seedling established and is therefore important for plant ecology and agriculture. Several processes are known to be involved in the induction of dormancy and in the switch from the dormant to the germinating state.
What are the types of dormancy?
There are three types of dormancy based on their mode of action: physical, physiological and morphological.
What is the process of dormancy?
Dormancy is a period in an organism’s life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions.
What are the hormones of seed germination and dormancy?
Most recent findings regarding seed germination and dormancy are reviewed. The significance of plant hormones including abscisic acid, ethylene, gibberellins, auxin, cytokinins and brassinosteroids, with reference to proteomic and molecular biology studies on germination, is also discussed.
How is the dormancy of a seed determined?
Seed dormancy is an innate seed property that defines the environmental conditions in which the seed is able to germinate. It is determined by genetics with a substantial environmental influence which is mediated, at least in part, by the plant hormones abscisic acid and gibberellins.
What is the role of ABA and gas in seed dormancy?
A dynamic balance of synthesis and catabolism of two antagonistic hormones, abscisic acid (ABA) and giberellins (GAs), controls the equilibrium between seed dormancy and germination. Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth.
What are the hormones that affect plant growth?
The significance of plant hormones including abscisic acid, ethylene, gibberellins, auxin, cytokinins and brassinosteroids, with reference to proteomic and molecular biology studies on germination, is also discussed. This review article contains almost a complete set of details, which may affect seed biology during dormancy and growth.