Seed Germination and Dormancy

SEED GERMINATION AND SOWING OPTIONS

• Seed dormancy is an adaptation ensuring germination only under favorable conditions for survival. This variability is advantageous, as it ensures germination at different times, exposing some to favorable conditions for survival.
• Horticultural practices can discourage or encourage dormancy.
• Plant species experience different types of dormancy (internal and/or external).
• Internal dormancy can be physiological, morphological, or both.
• Physiological dormancy is overcome by environmental conditions like cold and moisture.
• Morphological dormancy is overcome when the embryo fully matures through a period of after-ripening.
• Nondormant seeds germinate immediately after maturation and dispersal.
• Dormant seeds may take months or even years to germinate.
• Dormancy can be influenced by internal or external factors, sometimes both (double dormancy).

TYPES OF SEED DORMANCY

• Nondormant seeds germinate immediately after dispersal.
• Dormant seeds will not germinate, even under ideal conditions, and may take months or years before germinating.

TREATMENTS TO OVERCOME DORMANCY AND ENHANCE GERMINATION

• Various treatments (e.g., temperature, water, smoke) are employed to break dormancy.
• These treatments vary by species, reflecting species-specific needs and environmental responses
• Treatments for species with hard seed coats (e.g., sulfuric acid).
• Heat treatments (e.g., dry/wet).
• Gibberellic acid, ethylene, and even smoke are used to enhance germination in many plant species.

GERMINATION STIMULATORS

• Gibberellic acid, a plant hormone, is often used to regulate internal dormancy.
• Ethylene gas can be used to stimulate germination in certain species.
• Smoke treatments, common in ecosystems, are used.
• Chemical treatments are used to break dormancy in species with thick seed coats.

ENVIRONMENTAL FACTORS INFLUENCING GERMINATION

• Light, water, oxygen, and temperature are crucial factors for germination.
• Species-specific requirements exist.
• Specific germination requirements (e.g., temperature ranges, oxygen availability, humidity) should be considered.
• Mulch is used to create optimal conditions.

VEGETATIVE PROPAGATION

• Many species reproduce vegetatively.
• Vegetative propagation involves propagating species without seeds.
• Several methods exist for vegetative propagation (e.g., cuttings, tubers, rhizomes).
• Several factors influence choice of propagation method (i.e plant species, desired characteristics)

CUTTING STRIKING

• Cuttings are parts of plants used for vegetative propagation,
• Types of cuttings (e.g., shoot, stem, root).
• Considerations using cuttings: seasonal timing, plant characteristics (species-specific needs).
• Factors influencing success: environmental conditions, correct handling.

This quiz explores the concepts of seed germination and dormancy. It covers types of dormancy, factors affecting germination, and horticultural practices that influence these processes. Test your knowledge of how seed dormancy ensures survival and the different mechanisms involved.