1. Angiosperm Reproduction
Chapter 38
Angiosperm Reproduction

2. What you need to know: The relationship between seed and fruit.
How temperature and moisture determine seed germination.
How different modes of plant reproduction affect their genetic diversity.

3. Angiosperms have 3 unique Features:
Flowers
Fruits
Double Fertilization

5. SYMMETRY
OVARY LOCATION
FLORAL DISTRIBUTION
Bilateral symmetry
(orchid)
Lupine inflorescence
Superior
ovary
Radial symmetry
(daffodil)
Sunflower
inflorescence
Semi-inferior
ovary
Inferior
ovary
Sepal
Fused petals

6. REPRODUCTIVE VARIATIONS
Maize, a monoecious species
Dioecious Sagittaria latifolia (common
arrowhead)

7. Pollination: transfer pollen from anther to stigma
Pollen tube grows down into ovary for 2 sperm to travel to egg

8. “Pin” and “thrum” flower types reduce self-fertilization
Some plants are self-pollinated
Cross-pollinated plants:
Self-incompatibility: plant rejects own pollen or closely related plant
Maximize genetic variation
Stigma
Pin flower
Anther
with
pollen
Thrum flower
“Pin” and “thrum” flower types reduce self-fertilization

9. The development of a plant embryo

10. Fruit Egg cell  plant embryo Ovules inside ovary  seeds
Ripe ovary  fruit
Fruit protects enclosed seed(s)
Aids in dispersal by water, wind, or animals

11. Types of Fruit

12. Seeds Mature seed  dormancy (resting) Low metabolic rate
Growth & development suspended
Resumes growth when environmental conditions suitable for germination

13. Seed Structure

16. Germination
Seed take up water (imbibition)  trigger metabolic changes to begin growth
Root develops
Shoot tip emerges above ground
Stimulated by light
Foliage leaves expand & turn green  photosynthesis
Very hazardous for plants due to vulnerability
Predators, parasites, wind

17. Seed Germination

18. (Vegetative Reproduction)
Plant Reproduction
Sexual
Asexual
(Vegetative Reproduction)
Flower  Seeds
Runners, bulbs, grafts, cuttings
vegetative (grass), fragmentation, test-tube cloning
Genetic diversity
Clones
More complex & hazardous for seedlings
Simpler (no pollinator needed)
Advantage in unstable environments
Suited for stable environments

19. Asexual reproduction in aspen trees

20. Test-tube cloning of carrots
Just a few parenchyma cells from a carrot gave rise to this callus, a mass of undifferentiated cells.
The callus differentiates into an entire plant, with leaves, stems, and roots.

21. Humans Modify Crops Artificial selection of plants for breeding
Plant Biotechnology:
Genetically modified organisms
“Golden Rice”: engineered to produce beta-carotene (Vit. A)
Bt corn: transgenic – expresses Bt (bacteria) gene  produces protein toxic to insects
Biofuels – reduce CO2 emissions
Biodiesel: vegetable oils
Bioethanol: convert cellulose into ethanol