Angiosperm Plant Reproduction (Chap. 28)

1. Angiosperm Plant Reproduction (Chap. 28) Know the following in a typical plant: • sepal, petal, stamen, anther, filament, pollen, pistil, stigma, style, ovule, and ovary

2. Sexual Reproduction Pollination • the transfer of pollenfrom an anther to a stigma • some flowers’ color, shape, and fragrance attract pollinators and others simply use wind

3. Fertilization • a zygote is formed by the fusion of a male gamete (a pollen grain produced by the anther) and a female gamete (ovules in the ovaries) • Process • after pollination, one cell in the pollen grain called the tube cell makes enzymes that digest the tissue ahead of it and the pollen grain progresses through the style towards the ovary

4. two other cells in the pollen grain called sperm cells finally penetrate the ovule (various maternal cells) in the ovary in a process called double fertilization • one sperm fertilizes the egg cells that eventually becomes the zygote • other sperm fertilizes the central cell that produce the endosperm (nutritive tissue in seeds)

5. (sperm cell)

8. Seed Dormancy and Dispersal • lose most of their water and can lie dormant up to 10,000 years • primarily dispersed by wind, water, and animals (inside and outside)

9. Germination of the Seed Conditions needed for germination • Waterto re-hydrate the dry tissue and the hydrolysis of storage compounds such as starch into their simple monomers such as glucose. • Oxygenis needed for aerobic respiration • Seeds have an optimum temperature for enzymatic activity leading to germination.

10. Metabolic events of germination • Absorption of water to rehydrate living cells in the seed and cause it to burst • Water activates a plant hormone gibberellin • Gibberellin stimulates the production of amylase (that catalyzes the digestions of starch into maltose) and then maltose is hydrolyzed by maltase into glucose.

11. 4. The embryo absorbs glucose and uses it for respiration 5. Cell division, growth and elongation occur in the embryo . The radicle starts growing downwards into a root and the plumule starts growing upwards into a shoot. 6. As the nutrients in the cotyledons are consumed and exhausted, the first leaves start to appear and the plant starts to photosynthesize and make its own food.

12. Asexual Reproduction Vegetative propagation • the development of new individuals from a fragment of the plant • genetically identical to the parent plant • ensures desirable qualities of a crop • 5 types that occur in some plants 1. cuttings – cut and put pieces of stem in water

13. 2. adventitious buds (suckers) – buds form on underground roots or stems 3. leaf generation – shoots emerge on the margins of a leaf

14. 4. runner or stolons – wispy stems that snake away from the parent plant and eventually develop roots and stems. ex) strawberries 5. tubers – thick underground stems. ex) potatoes

15. Apomixis • seeds produced without the union of sperm and egg • egg fails to under go meiosis and diploid condition is retained • occurs naturally in about 400 plant species • can be good in extreme environmental conditions however lack the variability that is necessary for evolution of the plant