Reproduction in lower and higher plants notes part 3
Microsporogenesis - 1. Process of formation of Microspores by meiosis from MMC - Microspore Mother Cell 2. Pollen grain- Non-motile with single nucleus. 3. Pollen wall, double layered - Sporoderm 4. Pollen wall- Exine (outer wall) Intine (inner wall) Exine (outer wall) Thick Composed of non- biodegradable sporopollenin Protective layer Smooth or variously sculptured, spiny Presence of thin areas germ pores for emergence of pollen tube Intine (inner wall) Thin Cellulose and pectin Forms pollen tube Smooth 5. Pollen Viability : It is the ability of pollen grain to germinate and develop male gametophyte. Depends on environment factors – Temperature and humidity. It lasts for few minutes (Grasses, Wheat, Rice) to months (Members of Rosaceae, Solanaceae, Fabaceae, Leguminosae) 6. Development of male gametophyte : It is considerably reduced. Develops in flower. Pollen grain (n) is first cell of gametophyte. 7. Pollen grain- 1. First mitotic division → 2 unequal cells → Ve...
