Plant Form and Function

1. Plant Form and Function Learning Goal: How are plants structurally adapted for survival? Concept 3: Analyzing how plants detect and defend themselves against herbivores and environmental stresses (Ch 39) Refer to pg 219-222 in HoltzclawCh 39 in Campbell Media resources Get your Evolution question ready!

2. Checkpoint Next Class: • Concept 1: Analyzing the structure, growth, development and nutrition of plants (Ch 35, 37) • Concept 2: Analyzing the reproduction of angiosperms and modifications through biotechnology (Ch 38) • Concept 3: Analyzing how plants detect and defend themselves against herbivores and environmental stresses (Ch 39) Don’t forget to connect to the AP Themes!

3. Try This! Which of the following constitute plant macronutrients? • Potassium, oxygen, hydrogen and zinc • Carbon, oxygen, nitrogen and copper • Carbon, oxygen, nitrogen, and hydrogen • Carbon, boron, nitrogen, and chlorine • Phosphorus, oxygen, nitrogen and iron

4. Try This! Which of the following constitute plant macronutrients? • Potassium, oxygen, hydrogen and zinc • Carbon, oxygen, nitrogen and copper • Carbon, oxygen, nitrogen, and hydrogen • Carbon, boron, nitrogen, and chlorine • Phosphorus, oxygen, nitrogen and iron CHNOPS!!

5. Try This! In double fertilization, how is the endosperm formed? • The fusing of two sperm and an egg • From the epidermis • From the fertilization of the egg • From the zygote during development • From the fusing of a sperm with two polar bodies

6. Try This! In double fertilization, how is the endosperm formed? • The fusing of two sperm and an egg • From the epidermis • From the fertilization of the egg • From the zygote during development • From the fusing of a sperm with two polar bodies

7. From Last Class… Free Response • Page 820 in Campbell – Assess next class • # 12 Evolution Connection With respect to sexual reproduction, some plant species are fully self-fertile, others are fully self-incompatible, and some exhibit a “mixed strategy” with partial self-incompatibility. These reproductive strategies differ in their implications for evolutionary potential. How, for example, might a self-incompatible species fare as a small founder population or remnant population in a severe population bottleneck (see Ch 23), as compared with a self-fertile species?

8. From Last Class… Free Response Free Response – Evolution Connection Small populations of self-incompatible species, whether due to being founding populations or to bottleneck, would be at a disadvantage relative to self-fertile species. Small populations already have significant challenges in avoiding extinction. Adding the fact that they cannot perform sexual reproduction independently of other organisms merely adds to the list of challenges.

9. Concept 3: Analyzing how plants detect and defend themselves against herbivores and environmental stresses (Ch 39)

10. Concept 3: Analyzing how plants detect and defend themselves against herbivores and environmental stresses (Ch 39) You must know: The three steps to a signal transduction pathway The role of auxins in plants The survival benefits of phototropism and gravitropism How photoperiodism determines when flowering occurs

11. Try This! Both plants and animals respond to environmental stimuli. Which of the following statements are true and which ones are false? • The processes by which plants and animals perceive environmental changes are equally complex. • The processes by which plants and animals perceive environmental changes are often homologous. • Unlike animal hormones, plant hormones act only locally. • Both plants and animals have physiological cycles called circadian rhythms.

12. Try This! Both plants and animals respond to environmental stimuli. Which of the following statements are true and which ones are false? • The processes by which plants and animals perceive environmental changes are equally complex.TRUE • The processes by which plants and animals perceive environmental changes are often homologous.TRUE • Unlike animal hormones, plant hormones act only locally. FLASE • Both plants and animals have physiological cycles called circadian rhythms.TRUE

13. Try This! • What are the morphological differences in dark-grown plants and light-grown plants?

14. Try This! • What are the morphological differences in dark-grown plants and light-grown plants? • Dark- grown have • long stems • underdeveloped roots • unexpanded leaves • shoots lack chlorophyll But, WHY?

15. How does this potato change its growth when there is light?

16. How does this potato change its growth when there is light? • Via the Signal Transduction Pathway!

17. How does this potato change its growth when there is light? • Via the Signal Transduction Pathway! • The signal (light) is transduced to a response (greening)

18. Signal Transduction - Review • Reception • Transduction • Response

19. Signal Transduction - Review • Reception: Receptors undergo changes in shape due to an environmental stimulus • Ex) phytochrome proteins changing in response to light

20. Signal Transduction - Review • Transduction: Amplification of signal through a multistep pathway • Allows small signal to produce large cellular response • Uses protein kinases (phosphorylation cascade) and second messengers (Ca2+ and cAMP)

21. Signal Transduction - Review • Response: Two ways response is accomplished: • Transcriptional Modification: • ↑ or ↓ mRNA production (turning genes on/off) • Post-Translational Modification: • Activates existing enzyme molecules

22. Signal Transduction • For example, affected proteins for this potato exposed to light include: • Photosynthesis enzymes • Plant growth hormones • Auxin levels lower to slow stem growth (focus on leaf growth)

23. So…. What was AUXIN? • A plant hormone… • Yes, plants have hormones too!

24. Examples of Plant Hormones • Auxins – stimulate elongation of cells within young developing shoots • Cytokinins – stimulate cell division • Gibberellins – stimulate stem elongation, pollen, fruit, seed development • Abscisic acid – promotes stomatal closure during drought stress • Ethylene (gas!) – fruit ripening, leaf abscission

25. Plant Hormones • Hormones: chemical messengers that coordinate the different parts of a multicellular organism • Tropism: Plant growth response toward or away from a stimulus • Phototropism • Gravitropism • How does this benefit survival?

26. Phototropism - Mechanism

27. Phototropism - Mechanism

28. Phototropism - Mechanism

30. Actions of hormones… • Photoperiodism – physiological response to a photoperiod (relative lengths of day and night) • Example: Flowering • Short day plants • Long day plants • Day-neutral plants • Circadian rhythms – physiological cycles that have a frequency of about 24 hours

31. Responses to Mechanical Stimuli • Mimosa Plant

32. Herbivore Defense Video Clip

33. Think: • Illustrate this statement with an example: “A plant generally responds to environmental cues by adjusting its pattern of growth and development.”

34. How do plants detect and defend themselves against herbivores and environmental stresses? Do you know? The three steps to a signal transduction pathway The role of auxins in plants The survival benefits of phototropism and gravitropism How photoperiodism determines when flowering occurs

35. Checkpoint Next Class: • Concept 1: Analyzing the structure, growth, development and nutrition of plants (Ch 35, 37)# 12, 13, 15, 16, 20, 21, 24 in Holtz • Concept 2: Analyzing the reproduction of angiosperms and modifications through biotechnology (Ch 38)#5, 22, 23 in Holtz • Concept 3: Analyzing how plants detect and defend themselves against herbivores and environmental stresses (Ch 39)# 1, 2, 7, 8, 9, 10, 11, 14, 25 in Holtz Don’t forget to connect to the AP Themes!