Seed Physiology and Germination

Study Notes

Seed Physiology

Seed formation involves several steps, including the development and maturation of the embryo.
Seed development is influenced by physiological processes, leading to seed ripening and maturation.
Seeds are composed of various chemical components, including carbohydrates, lipids, proteins, and other compounds.
Storage reserves like lipids, proteins, and carbohydrates are synthesized and accumulated within the seed.
Seeds develop desiccation tolerance, a crucial adaptation for survival.
Hormones play a vital role in regulating fruit and seed development.

Seed Germination and Metabolism

Seed germination is influenced by both external and internal factors.
External factors include environmental conditions like temperature, moisture, and light.
Internal factors encompass seed characteristics like seed maturity, dormancy, and viability.
Germination involves a series of physiological processes: water imbibition, enzyme activation, embryo growth, seed coat rupture, and seedling emergence.
Seedling establishment is the final stage of germination, where the seedling begins to grow independently.
The embryonic axis plays a critical role in germination, along with growth hormones and enzyme activities.
Seed age, size, and position can influence germination.
During germination, storage reserves (carbohydrates, lipids, proteins) are metabolized to provide energy for the developing seedling.
Respiration is an indicator of overall metabolic activity in germinating seeds.

Seed Germination and Dormancy

Seeds exhibit different germination patterns, categorized as epigeal (cotyledons above the ground) and hypogeal (cotyledons remain below the ground).
The morphology of dicotyledonous and monocotyledonous seedlings differs, reflecting their unique developmental patterns.
Seed germination patterns vary across species, as exemplified by pea, chickpea, castor, soybean, radish, maize, and wheat.
Seed dormancy is a state of arrested development, preventing germination despite favorable conditions.
Dormancy is classified into different types, each with its own significance and underlying mechanisms.
Both endogenous (internal) and exogenous (external) factors regulate dormancy.
Impermeable seed coats can contribute to seed dormancy.
Phytochrome, a light-sensitive pigment, and plant growth regulators (PGRs) play a role in dormancy.
Genetic factors also influence seed dormancy.

Seed Viability and Deterioration

Seed viability refers to the ability of a seed to germinate under optimal conditions.
Pre- and post-harvest factors impact seed viability, influencing its longevity.
Seed deterioration is a gradual decline in seed quality, manifested by reduced germination potential and vigor.
Symptoms of seed deterioration include decreased germination rate, abnormal seedling growth, and reduced field emergence.
Seed deterioration results from various causes, including aging, improper storage, and environmental stress.
Lipid peroxidation is a key process involved in seed deterioration.
Various theories attempt to explain seed viability and deterioration.
Maintaining optimal storage conditions and adopting specific techniques can prolong seed viability.
Seed longevity is influenced by factors like species, variety, and storage conditions.
Desiccation sensitivity and recalcitrance are crucial considerations for seed longevity.

Seed Vigor and Longevity

Seed vigor is a measure of seed quality, encompassing its ability to germinate rapidly and produce strong, healthy seedlings.
Seed vigor is influenced by factors like genetics, seed maturity, and storage conditions.
Longevity refers to the duration for which a seed remains viable and capable of germination.
Seed longevity is influenced by species, variety, genetics, and storage conditions.
Maintaining high levels of seed vigor and longevity is essential for successful crop production.

Description

Explore the intricacies of seed formation, development, and germination in this informative quiz. Learn about the physiological processes that influence seed maturity, the chemical composition of seeds, and the factors that affect germination. Test your knowledge on how hormones and environmental conditions play a critical role in these processes.