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Botany Overview

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  1. Botany Overview • 1st Remarks: • “Plants Can’t Run” • Plants have covered the globe. • The basic information is usually the most important.

  2. What’s here? • Overview of plant evolution and plant clades • Overview of plant growth and development • Overview of Plant Transport • Overview of Photosynthesis • Overview of Plant Response to the Environment

  3. What if you can’t run and you can’t eat? Major Balancing Act Major Challenge

  4. Who are the Land Plants? Shared Primitive Characters: Shared Derived Characters: Table 29.1 (578)

  5. Commonality: Alteration of Generations

  6. Sporophyte changes as plants become more derived. Table 29.1 (578)

  7. Bryophyte Life Cycle

  8. Modern Pterophytes are usually found in moist places…why?

  9. Alteration of Generations: Pterophytes

  10. SOUTHERN COASTS "a vast forest of the most stately pine trees that can be imagined, planted by nature at a moderate distance. . . enameled with a variety of flowering shrubs." Fire defined where the longleaf pine forest was found and fostered an ecosystem diverse in plants and animals.

  11. Gymnosperm Lifecycle

  12. All Hail The Mighty Flower! • Beauty • Ingenuity • Dominance • Support • Evolution/Classification

  13. Ingenuity 3: Double Fertilization What is a seed? What is a fruit?

  14. Meristems: Apical & Lateral

  15. Meristems: Apical & Lateral

  16. Secondary Growth Initials!

  17. One more look @ 2ndary Growth

  18. Over all transport in Plants: Major Balancing Act Major Challenge 3 “transport regions”: xm: ctc: wp:

  19. Transmembrane (xm) Transport: mediated by transport proteinsand “set up” by chemiosmosis (proton pumps) Membrane Potential

  20. Results of a chemo-electrical gradient…good stuff for the plant

  21. Apoplastic, symplatic, so what?

  22. These cellular processes lead to whole plant transport(aka Bulk Flow) • Hydrostatic pressure pulls sap down • Tension pulls sap (water) up • Facilitated by changes in water potential between neighboring cells • Diffusion/Osmosis • Active Transport • Vessel structure leads to increased transport efficiency • Xylem: • Dead… • Phloem: • So what…

  23. Accent of Xylem Sap: Differences in Water Potential! • Facilitated by the physical properties of water • Adhesion/Cohesion • Water molecules on the march!

  24. Plant Transport HO 1: Overview of Xylem Transport ?

  25. Phloem Loading: Source-Sink Phloem Sap: 30% sugar (sucrose) by volume! Sugar Source: … Sugar Sink: …

  26. Transpiration on a cellular level How does water move up to the leaves? It can be pushed… It can be pulled… How powerful is transpiration? Fig. 36.12 Page 747

  27. Regulation of transpiration occurs at the stomata, thanks to… Structure and Function Are correlated Regulation of Stomatal Opening: K+ Transport & Turgor Pressure *Light *CO2 *Circadian Rhythms

  28. Bioenergetics: Background Info • Producers • Consumers

  29. Across four levels of organization • Plants • Leaves • Mesophyll Cells • Chloroplasts

  30. PS: 2 Reactions in 1 organelle

  31. Food for thought: How are cellular respiration and photosynthesis similar? How are they different? Think about it on an organismal level, on an organelle level, and on a biochemical level.

  32. More Food…Check out Figure 10.16

  33. So What? • So what happens when light is absorbed? photosystem

  34. If we could get down on the thylakoid membrane…

  35. No, really, so what? • Where does the electron from water go once it replaces the electron in the chlorophyll molecule in the center of PSII (PS 680)?

  36. What happens? Well, chemiosmosis happens.

  37. What do the Light Reactions produce? • Light Reactions…

  38. But chloroplasts still needs a little more ATP

  39. Light Reaction Review…

  40. Gimmie Some Sugar!

  41. Phase 1: Carbon Fixation

  42. Phase 2: Reduction

  43. Phase 3: Regeneration of RuBP

  44. Photosynthesis: The Big Picture Location Energy conversions Material inputs/outputs

  45. Photorespiration • A drain on Calvin Cycle Energy that produces no ATP, it does produce CO2 • Why? Rubisco has an affinity for O2 • …and when [O2] build up in cells (and [CO2] drop)… • Rubisco binds RuBP to O2 instead of CO2 • Why? Rubisco evolved before O2 concentrations were appreciable in atmosphere • Can drain as much as 50% of photosynthetic energy away.

  46. Fighting Photorespiration the C4 way • High Light, High heat (think Corn). • What happens when it gets too hot, and transpiration increases? • What happens to [CO2] and [O2]? • How do plants combat this? • Fix CO2 into PEP Carboxylase • (4-C compound) • Deliver 4-C compound to Calvin Cycle in Bundle Sheath (where [O2] are lower. • Perform Calvin Cycle in Bundle Sheath • Transport Sugars (Sucrose) to Phloem • Spatial Separation!

  47. Fighting Photorespiration the CAM way • What are conditions like in the desert? • What will the stomata do? • How will the plants get CO2? • Open stomata at night! • Fix CO2 into organic acids (Crussalean Acid Metabolism) at night, store in vaculoles • During day, when light is available… • Temporal Separation!

  48. Botany Overview • 1st Remarks: • “Plants Can’t Run” • Plants have covered the globe. • The basic information is usually the most important.

  49. Why Study Plant Hormones/Plant Responses to the environment? • Ties into the theme: “Plants can’t run.” • Allows us to look at cellular (and sub-cellular processes) and relate them to organism function. • Gives us a glimpse of how organisms respond to stimuli and interact with an ecosystem (abiotic and biotic forces). • In a sense, this is physiological ecology