1. Chapter 38
Angiosperm Reproduction

2. Angiosperm Reproduction
Angiosperms have 3 unique features:
Flowers, Fruits, & Double Fertilization
Microsporangia
Pollen sacs in the anther
Diploid cells = meiosis  male gametophyte (pollen)
Pollen has 2 haploid nuclei
Tube nucleus – 1 sperm develops into a pollen tube
Generative nucleus – divides into 2 sperm cells which remain inside the pollen tube

4. Ovary Ovules form with a diploid cell Soon 4 haploid megapsores form
Eventually get 8 haploid nuclei, but only 3 are most important
1 haploid nucleus = egg
Will combine with sperm nucleus to form the zygote
2 other nuclei are called polar nuclei
Polar nuclei will fuse with sperm nucleus to make 3n endosperm

5. Watch Animation
38-01.swf

8. Pollination Pollen lands on stigma Pollen tube made from pollen grain
Pollen tube grows down into the ovary
When pollen tube reaches ovule, double fertilization occurs

9. Double Fertilization
Double fertilization is the union of 2 sperm cells forming zygote & endosperm
Unique to angiosperms
1 sperm fertilizes the egg  zygote
Zygote develops into the embryo  sporophyte
Other sperm combines with both polar nuclei = 3n nucleus
This 3n tissue  endosperm
Endosperm – food storing tissue in the seed

10. After double fertilization
Ovule develops into a seed
Ovary develops into fruit which encloses the seed
Fruit protects the enclosed seed
Fruit aids in dispersal by wind or animales
Seed coat – protects embryo & its food supply
Radicle – embryonic root
Epicotyl – shoot tip with pair of miniature leaves

12. Seed As the seed matures, It goes dormant
Low metabolic rate, growth and development are suspended
Seed resumes growth given suitable environmental conditions for germination

13. Asexual Reproduction in Plants
Asexual reproduction in plants is called vegetative reproduction
Fragmentation
Type of vegetative reproductive
When a part of the parent plant is separated and then generates into a new plant, genetically identical to parent plant
Self-fertilization is another means of asexual reproduction