– Types of Scarification:
– Scarified seeds do not store well and need quick planting.
– Mechanical scarification is the most common type.
– Methods include filing, rubbing, nicking, cracking, or weakening seed coats.
– Temperature scarification involves hot water or thermal treatment.
– Chemical scarification mimics natural processes using acids, bases, or chemicals.
– Mechanical Scarification:
– Involves physically opening the testa for moisture and air.
– Methods include filing, rubbing, nicking, cracking, or weakening seed coats.
– Common type of scarification.
– Ensures seeds are more permeable to water.
– Facilitates controlled and uniform germination.
– Temperature Scarification:
– Hot water treatment accelerates sprouting for some species.
– Seeds are soaked in boiling water and cooled before sowing.
– Hot water treatment can kill pathogens.
– Thermal scarification may require fire for germination.
– Buoyancy of seeds can be overcome using gravity.
– Chemical Scarification:
– Mimics natural stomach acids to promote germination.
– Involves soaking seeds in acidic or basic solutions.
– Chemicals like sulfuric acid or potassium nitrate can be used.
– Artificial process to soften seed coats.
– Chemical scarification increases germination rates significantly.
– Common Uses of Scarification:
– Scarified seeds germinate faster and more frequently.
– Widely used in industry and small-scale gardening.
– Facilitates germination of difficult-to-grow seeds.
– Helps in controlled and uniform germination.
– Speeds up natural germination processes.
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. Any process designed to make the testa (seed coat) more permeable to water and gases is known as scarification.
Scarification, regardless of type, works by speeding up the natural processes which normally make seed coats permeable to water and air. For drupes (stone fruits), scarification also extends to weakening or removal of the hard endocarp shell around the seed.