1. Flowering Plants - Reproduction
Chapter 35

2. Angiosperms The largest and most successful group of plants
Can reproduce both sexually and asexually
Advantages:
Sexual – genetic variation
Asexual – rapid and efficient
Disadvantages:
Sexual – requires time and energy
Asexual – lack of genetic variation

3. Alternation of Generations
Diploid sporophyte generation – larger and nutritionally independent
Produces haploid spores by meiosis
Haploid gametophyte generation – located in the flower; microscopic and totally dependent on the sporophyte
Gives rise to the gametes by mitosis

5. Flower structure Complete flowers: All four whorls
Sepals (all together = calyx)
Petals (all together = corolla)
Stamen – male flower part
Filament, anther
Carpel (a.k.a. pistil) – female flower part
Stigma, style, ovary

7. Pollination
Self-pollination – within the same flower or another flower on the same plant
Cross-pollination – pollen grains travel to another plant
Insects, birds, small mammals, wind and water can all serve as agents

8. Tricks to prevent inbreeding
Self-pollination reduces genetic variation and may concentrate ‘bad’ genes
Incomplete flowers – separate male and female flowers
Timing variation – pollen is shed at a time when stigma is not receptive
Self-incompatibility – a plant has the ability to identify and reject its own pollen

9. Coevolution
Plants and their animal pollinators are usually closely adapted to each other
Colors, scents
Animals may also have adaptations
Physical features and even behavior

10. Fertilization Pollen grains lands on stigma
One cell grows a thin pollen tube through the style to the ovary
The 2nd cell in the pollen grain divides to form 2 sperm cells which travel down the tube to the ovule
One sperm cell fertilizes the egg and form a zygote
The other sperm cell joins with 2 polar nuclei and forms a triploid endosperm which will nourish the embryo
This process is called double fertilization

11. Seeds
Contain an embryonic plant and food stored in the cotyledons or endosperm
Surrounded by a protective seed coat
Germination – seed sprouts and relies on stored food until leaves are functional
Fruits are mature, ripened ovaries

13. Asexual reproduction
Rhizome – horizontal, underground stem that can branch in many directions
Bulb – underground bud with thick leaves that store food
Runners – horizontal, aboveground stems
Suckers – shoots that branch off of underground roots