**Group 1: Seed Germination Process**
– Germination is the growth of a plant contained within a seed, resulting in the formation of a seedling.
– Seeds contain an embryo and food reserves wrapped in a seed coat.
– Dormant seeds require specific stimuli to resume growth.
– Seed germination depends on internal and external conditions.
– Water, oxygen, temperature, and light are crucial for seed germination.
– Seeds need water for imbibition, which leads to the breaking of the seed coat.
– Water activates hydrolytic enzymes that break down food reserves for growth.
– Oxygen is required for seed metabolism and energy until leaves grow.
– Temperature affects metabolic and growth rates in seeds.
– Seed dormancy involves changes in membranes and plant hormones.
– Radicle appearance marks the end of germination and start of establishment.
**Group 2: Factors Affecting Germination**
– Water, nutrients, and light are essential for seedling growth.
– Oxygen in soil pore spaces is essential for seed germination.
– Some plants like rice can undergo anaerobic germination in waterlogged conditions.
– Seeds have specific temperature ranges for germination.
– Cold stratification breaks dormancy for some seeds.
– Scarification weakens seed coat for germination triggers.
– Light is an environmental factor that stimulates the germination process.
– Seeds sense environmental cues to determine the perfect time to germinate.
– The balance between gibberellin (GA) and Abscisic acid (ABA) is crucial for seed dormancy and germination.
**Group 3: Germination Rate and Capacity**
– Germination rate indicates the likelihood of seeds to sprout over a specific period.
– It is expressed as a percentage and influenced by genetic, morphological, and environmental factors.
– Useful for determining seed quantity needed for planting.
– Seed germination rate is the reciprocal of the time taken for germination.
– Germination capacity refers to the number of seeds in a population able to complete germination.
**Group 4: Repair of DNA Damage during Germination**
– Seed quality declines with age due to genome damage accumulation.
– Repair processes are activated during germination to address DNA damage.
– DNA single- and double-strand breaks can be repaired.
– The DNA damage checkpoint kinase ATM plays a crucial role in germination and repair.
– Aging seeds accumulate DNA damages that need repair during germination.
**Group 5: Types of Germination (Dicot and Monocot)**
– Germination stages include radicle emergence, cotyledon growth, and shoot development.
– Epigeal germination occurs above ground, with the hypocotyl forming a hook.
– Hypogeal germination involves the elongation of the epicotyl.
– Monocot seeds have coleorhiza and coleoptile covering the embryo.
– Coleorhiza emerges first, followed by the radicle and coleoptile.
– Precocious germination skips some seed development stages.
Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ferns, bacteria, and the growth of the pollen tube from the pollen grain of a seed plant.
