Seed germination - types and phases of germination.pptx

Seed germination - types and phases of germination

1. Seed germination - types and phases of germination 1 . Seed: A seed is a ripened ovule, which consists of an embryo and stored food supply surrounded by protected seed coverings. 2. Embryo: A miniature plant within a seed, produces by the union of male and female gamete. 3. Germinate: To being to grow. 4. Germination: The process in which seed embryo starts growing, which leads to the development of seedling. 5. Dicots: Plants having two cotyledons in their seeds.

2. P hases of germination Activation or awakening stage : Water absorption : Imbibition/Osmosis (Seed coat rupture) Synthesis and activation of enzymes Cell elongation : Emergence of radicle is the first visible symptom of germination, which results from the elongation of cells rather than from the cell division Translocation and conversion stage: food translocation to growing embryo Fat/oils------Fatty acids------Sugars Storage proteins-------AAs----Nitrogen Starch----- simple sugars increase in respiration and assimilation Seedling growth stage: The Development Of The Embryonic Axis Into A Seedling increase in cell division and enlargement and vii. differentiation of cells into tissue and organs of a seedling.

3. The radicle, the growing point of root emerges from the base of the embryo axis and the plumule , the growing point of shoot is at the upper end of embryo axis, above the cotyledons. The section of seedling stem above the cotyledons is called as epicotyl and below the cotyledons is called as hypocotyl.

4. Types of seed germination : Seed germination in dicots in which the cotyledons remain below the soil surface . Example: gasses, maize, sorghum, rabi pulses Seed germination in dicots in which the cotyledons come above the soil surface . Examples: beans, groundnut, kharif pulses