1. 9.4 Reproduction in Angiospermophytes

2. I. Flower Structure & Function
Flowers are the reproductive structure of plants (4 parts)
1. sepals
2. petals
3. stamens
4. carpels
Flowering involves a change in gene expression in the shoot apex.
The switch to flowering is a response to the length of light and dark periods in many plants.

3. B. All 4 floral parts are important but only stamens (“male” organs) and carpels (“female” organs) produce gametes
C. A flower with all 4 parts is called “Complete”, if it doesn’t have all 4 parts it is called “incomplete”
D. A flower with both stamens & carpels is said to be “perfect”, whereas an “imperfect” flower has one or the other but not both
Complete flower

4. E. Functions of flower parts
Sepal
Protect flower
Petals
Colored leaves that attract pollinators
Anther
Male part of the flower that produces pollen
Filament
Males part of flower that hops up the anther
Stigma
Female part that contains sticky substance that pollen adheres to
Style
Female part that holds up the stigma and transfers sperm from pollen grain to ovary
Ovary
Female part that holds ovules (eggs)
Stamen
Collective male parts of the flower: anther and filament
Pistil
Collective female parts of the flower: stigma, style and ovary

5. Male & Female Flower Parts

6. II. Pollination & Fertilization
Pollination: placement of pollen onto the stigma of a carpel by wind, water or animal carriers; a pre-requisite to fertilization
1. Self Pollination
2. Cross pollination

7. B. Fertilization: the union of haploid gametes (pollen and egg) to produce a diploid gamete 1. Occurs within the ovary of a plant 2. Pollen tube grows down from the stigma to the ovary through the style 3. the gamete is now the seed

8. C. Seed Dispersal: action of the seed moving from its place of origin to another site where it will grow

9. III. Seed Structure Seed Part Function Testa (seed coat)
Tough, protective outer coat
Cotyledons
Embryonic leaves that function as nutrient storage structures
Micropyle
Scar of the opening where the pollen tube entered the ovule
Embryonic root
Becomes plants root system
Embryonic shoot
Becomes plants first leaves
Hilum
Scar left on seed from where it is attached to the ovary

11. IV. Germination Germination is the development of a new plant
Conditions needed for Germination
1. water to rehydrate dried seed tissues
2. Oxygen aerobic respiration to produce ATP.
3. Ideal temperature and pH for enzyme activity
4. Some seeds need special conditions to germinate
a. fire
b. testa disruption
c. freezing

12. 5. Seeds do not carry out photosynthesis
Seeds use used energy stored in cotyledons for cellular processes
This is in the form of amylose
Seed Germination

13. V. Seed Metabolism during Germination
Water is absorbed & activates cells
Synthesis of gibberelins (plant growth hormones)
Gibberelins cause synthesis of amylase
Amylase hydrolyses stored starch to maltose
Maltose is further broken down into glucose which is used for cellular respiration and converted into cellulose

15. VI. Phytochrome & Flowering
A. Photoperiodism: reaction of plants to the length of daylight (night is the critical time).
Plant Type
Flowering & Light
Examples
Long-Day Plants
Bloom when days are longest and nights shortest (midsummer)
Radishes, spinach and lettuce
Short-Day Plants
Bloom in spring, late summer and autumn when days are shorter
Poinsettias, chrysanthemums, and asters
Day-Neutral Plants
Flower without regard to day length
Roses, dandelions and tomatoes

16. B. Phytochrome: photoreceptor, a pigment in plants used to detect light. Sensitive to light in the red and far-red region -inactive form by red light (Pr) (660nm) -active form by far-red light (Pfr) (730nm) -moonlight produces a greater percentage of far-red light than sunlight, so during the night the phytochrome is slowly converted to its inactive form -more phytochrome is converted in a longer night, allowing the plant to measure the length of the night.

18. Monocots
Dicots
One cotyledon
Two cotyledons (embryonic leaves)
Parallel veins in leaves
Netlike veins in leaves
Floral organs in multiples of 3
Floral organs in multiples of 4 or 5
Vascular tissue in stems scattered
Vascular tissue in stems distributed in rings
Fibrous roots
Taproots with lateral branches
One pollen grain opening
3 pollen grain openings