Plant Biology

1. Plant Biology

2. Plant Reproduction BPS5

3. Objectives LESSON OBJECTIVE ENABLING OBJECTIVES • Diagram the processes of plant reproduction • Select proper sowing techniques to promote germination After completing this lesson on reproduction, students will demonstrate their ability to apply the concept in real-world situations by obtaining a minimum score of 80% on the How-To Demonstration evaluation. 01 02

4. Ponder This! How do we go from a seed to this plant and flower? How do these items represent the life cycle of plants? If this were the last plant or flower of its kind, how would we produce more?

5. Objective 1Diagram the processes of plant reproduction

6. Pollination • Process plants use to sexually reproduce • Transfer of pollen from the stamen to the pistil • Two types: • Cross-pollination • Self-pollination

7. Cross-Pollination When pollen from the stamen of one flower moves to the pistil of another flower

8. Self-Pollination When pollen from the stamen of a flower moves to the pistil of the same flower

9. Objective 2Select proper sowing techniques to promote germination

10. Sowing Techniques • Reproduction through seed • Also known as sexual propagation • Sowing is the act of placing the seeds in a growing media • Two types: • Direct • Indirect

11. Direct Sowing • Seeds are planted directly where they will grow • No transplanting • Example: corn or soybeans in field rows

12. Indirect Sowing • Seeds are planted and then transplanted to the final growing place • Transplanting can happen just once or multiple times • Example: Petunia seed sown in seedling flat, transplanted into 806 cell pack, transplanted into outdoor garden

13. Germination • Germination is the growth of the plant embryo • Germination factors: • Temperature • Light • Air • Moisture

14. Dormancy • Resting stage for seeds • Prevents seeds from germinating • Breaking dormancy: • Heat • Stratification – Seeds are planted in a moist growing medium at 32-50F for several weeks • Scarification – Seed coat is weakened through mechanically or chemically

15. Order of Germination • Water absorption • Enzymatic breakdown • Production of new cells; formation of new tissue • Emergence of seedling

16. Monocot • Seed swells as moisture is absorbed • Seed coat ruptures • Radicle grows down • First internode and epicotyl grow up • After epicotyl emerges, new leaves form and food production starts • New root system grows just beneath the soil above the first internode

17. Dicot • Seed swells as moisture is absorbed • Seed coat splits • The radicle emerges and grows down • The hypocotyl elongates, forms an arch and pulls the cotyledon upward • When the hypocotyl reaches light, elongation ceases, and the hypocotyl straightens up and pulls the cotyledons out of the soil • Cotyledons open, turn green and provide food until the true leaves develop • First true leaves unfold from the epicotyl, exposing the growth bud • Cotyledons die, dry up and fall off

18. Germination Rate You Plant 100 seeds and 75 germinate – What is your germination rate? 75/100 = .75 .75 x 100 = 75% Germination Rate – 75%

19. Germination Rate You planted 200 seeds that have an approximate germination rate of 80%. Approximately how many seeds are expected to germinate? 80/100 = .8 200 x .8 = 160 Seeds Expected to Germinate – 160

20. Germination Rate You planted 200 seeds that have an approximate germination rate of 80%. Approximately how many seeds are expected to germinate? 80/100 = .8 200 x .8 = 160 Seeds Expected to Germinate – 160

21. Germination Rate You have an order for 500 Petunias. The seeds you ordered have an expected germination rate of 90%. How many seeds do you need to plant to make sure you have enough to fill the order? S x 90% = 500 S = 500/90% 90/100 = .9 S = 500/.9 S = 555.55 Seeds needed to plant – 556