1. Chapter 38 n Plant Reproduction and Development

2. Sexual Reproduction n Alternation of generations: haploid (n) and diploid (2n) generations take turns producing each other n Sporophyte (2n): produces haploid spores by meiosis; these spores divide by mitosis giving rise to male and female haploid plants called…. n Gametophytes (n): develop and produce gametes

3. Floral variations n Floral organs: sepals, petals, stamens (male ), carpels (female) n complete: all 4 floral organs n incomplete: lacking 1 or more floral organs n perfect: both stamens and carpels on 1 flower n imperfect: lacking either a stamen or carpel n monoecious: staminate and carpellate flowers on 1 plant) n dioecious: staminate and carpellate flowers on separate plants

4. Gametophyte development n Male gametophyte: microsporocyte (in pollen sacs of anther) divides by meiosis into 4- 1N microspores; mitosis produces a generative cell (sperm) and a tube cell (pollen tube)= a pollen grain n Female gametophyte: megasporocyte (in ovule) divides by meiosis to 4 cells, only 1 survives to a 1-N megaspore; 3 mitotic divisions forms the embryo sac; includes: 1 egg cell (female gamete) and 2 polar nuclei (synergids)

5. Double fertilization n Pollination (pollen grain lands on a receptive stigma) n Tube cell (pollen tube produced down the style) n Generative cell (2 sperm by mitosis) n Enters ovary through micropyle n 1 sperm fertilizes egg to form zygote; other sperm combines with 2 polar nuclei to form 3n endosperm (food-storing tissue)

6. Plant fertilization n http://youtube.com/wa tch?v=AWXb6z1eD0o http://youtube.com/wa tch?v=AWXb6z1eD0o http://youtube.com/wa tch?v=AWXb6z1eD0o

7. The seed n From fertilized ovule….. n The mature seed: n seed coat (protection) n cotyledons (seed leaves) n hypocotyl (lower embryonic axis) n radicle (embryonic root) n epicotyl (upper embryonic axis) n plummule (shoot tip) n coleoptile (sheath for embryonic shoot)

8. Seed development n http://www.youtube.co m/watch?v=3ZAMLej Nj- 4&feature=PlayList&p =00F901E6FF1C8B21 &playnext=1&playnex t_from=PL&index=26 http://www.youtube.co m/watch?v=3ZAMLej Nj- 4&feature=PlayList&p =00F901E6FF1C8B21 &playnext=1&playnex t_from=PL&index=26 http://www.youtube.co m/watch?v=3ZAMLej Nj- 4&feature=PlayList&p =00F901E6FF1C8B21 &playnext=1&playnex t_from=PL&index=26

9. The fruit n From ovary…. n Fruit protects seeds and aids in their dispersal n Pericarp (thickened wall of fruit from ovary wall) n Fruit types: nsimple (1 ovary/1 flower)~ cherry, soybean naggregate (1 flower with many carpels/ovaries)~ blackberry nmultiple (inflorescence; group of flowers/ovaries) ~ pineapple

10. Fruit development n http://www.youtube.co m/watch?v=bwCpQfl mQG4 http://www.youtube.co m/watch?v=bwCpQfl mQG4 http://www.youtube.co m/watch?v=bwCpQfl mQG4

11. Seed germination n Seed dormancy (low metabolic rate and growth suspension) n Imbibition (uptake of water) n Radicle 1st, then shoot tip (hypocotyl); stimulated by light n Germination