Seeds are protected by a seed coat (testa). In some species this physical barrier requires scarification (scratching, etching, or burning) or passage through an animal gut where acids or digestive enzymes can dissolve the barrier. These seeds have what is called 'physical dormancy.
Seed coat (external dormancy) results from a seed's hard seed coat that is impervious to water and gases. The seed will not germinate until the seed coat is altered physically. Any process of breaking, scratching, or mechanically altering the seed coat to make it permeable to water and gases is known as scarification.
Stratification is the mechanism of putting seeds under moist cold conditions for a specific period of time in order to overcome internal dormancy while scarification is the mechanism of scratching or removing seed coat in order to overcome physical dormancy.
Seed scarification methods have been developed and modified over time to make these more practical and effective. Important methods of seed scarification include heat, freeze-thaw, mechanical and acid scarification.
A dormant seed will not germinate when it will be exposed to the right environmental conditions (light and water). Seed dormancy can be broken by dry storage or by a cold imbibition (stratification). Seed germination in Arabidopsis is two-step: testa rupture followed by endosperm rupture.
Aestivation, also spelled estivation, is an example of consequential dormancy in response to very hot or dry conditions. It is common in invertebrates such as the garden snail and worm but also occurs in other animals such as lungfish, salamanders, desert tortoises, and crocodiles.
Seed dormancy is the state in which seed is unable to germinate, even under ideal growing conditions (Merriam-Webster). Because dormancy can be broken by most ideal growing conditions (different and specific for each species), the seeds germinate when they are the most likely to flourish.
Scarification is the cutting, burning, or branding of the skin to create scars in a set pattern or design. Some indigenous cultures have used scarification for centuries as a ritualistic practice. People in Western practices may choose the practice as a body modification method for aesthetic or self-expression reasons.
Scarification in botany involves weakening, opening, or otherwise altering the coat of a seed to encourage germination. Scarification is often done mechanically, thermally, and chemically. The seeds of many plant species are often impervious to water and gases, thus preventing or delaying germination.
noun. The act or result of making scratches or superficial incisions in the skin to produce an immune response or administer certain injections: Scarification is a common method of sensitizing the skin for contact with an allergen.
Scarification methods such as heat, mechanical, and acid scarification are useful tools to soften hard seed, improve germination, and enhance seedling establishment. The most effective scarification technique that can be used for the growth of long bean seeds is heating using an oven at 55oC (P5).
Artificial Overcoming of Seed Dormancy
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.
So, the correct answer is 'Scarification'.
Stratification is accomplished by placing seeds in moist planting medium in a cold environment for a period of time (two weeks to three months). Seeds require moisture, cold and oxygen. In general, this period of time allows an undeveloped embryo to mature.
Dormancy is classified into three types based on its mode of action: physical, physiological, and morphological. Physical dormancy is the most common type of seed dormancy found in the tropics.
Stratification is a general term that refers to a range of processes used to simulate natural conditions (typically temperature and moisture) that seeds require before germination can occur. Scarification refers to various techniques used to break physical dormancy (explained below).
Seed scarification is the process of altering the seed coat to allow quicker water absorption and improve rates of germination. The seed or caryopsis of eastern gamagrass needs scarification because it is encased in a thick hull (called a cupule) that is only slowly permeable to water.
Seed Scarification: nicking, breaking, softening, or otherwise weakening of the seed coating meant to speed up germination. You can see the hard, almost walnut-like seed coating on these Nasturtium seeds. For best germination, you can nick the outer coating and soak the seeds overnight before planting.
The main point of African scarification is to beautify, although scars of a certain type, size and position on the body often indicate group identity or stages in a person's life. Among the Dinka of Sudan facial scarification, usually around the temple area, is used for clan identification.
Heat, freeze-thaw, mechanical and acid scarification are among the most popular methods.
Types of Scarification
Mechanical involves physically opening the seed coating to allow air and water to enter. Chemical involves the use of chemicals to weaken the seed coating and encourage germination. Sulfuric acid is a commonly used chemical for this method.
Endogenous dormancy (inside the seed, related to the seed embryo), and. Exogenous dormancy (outside the seed, related to the seed coat or other surrounding tissue).
Dormancy. a period in which a plant does not grow, awaiting necessary environmentalconditions such as temperature, moisture, nutrient availability, etc. A state of quiet (but possibly temporary) inaction; the volcano erupted after centuries of dormancy. Quiet and inactive restfulness.
Dormancy is defined as the temporary inability of a viable seed to germinate under favorable environmental conditions (Simpson, 1990). Dormancy helps the seed to survive adverse environmental conditions and at the same time helps in seed dispersal (Snape et al., 2001).