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Course Plan We will study effects of stresses on plants and see where it leads us Phytoremediation

Course Plan We will study effects of stresses on plants and see where it leads us Phytoremediation Plant products Biofuels Effects of seed spacing on seed germination Effects of nutrient deprivation Effects of stresses Climate/CO 2 change Non-coding RNAs Biotechnology

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Course Plan We will study effects of stresses on plants and see where it leads us Phytoremediation

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  1. Course Plan • We will study effects of stresses on plants and see where it leads us • Phytoremediation • Plant products • Biofuels • Effects of seed spacing on seed germination • Effects of nutrient deprivation • Effects of stresses • Climate/CO2 change • Non-coding RNAs • Biotechnology • Plant movements: flytraps, mimosa, soybeans • Carnivorous plants • Stress responses/stress avoidance • Plant signaling (including neurobiology) • Flowering? • Hormones? • Plant pathology? • Plant tropisms and nastic movements • Root growth responses • Metal toxicity? • Circadian rhythms? • Effects of magnetic fields? • Effects of different colors of light on plant growth?

  2. We will study effects of stresses on plants and see where it leads us • Learn about plant stress

  3. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study

  4. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • Radishes • Onions • Cucumbers • Jalapenos • Indian mustard • Any more? • Soybean or other beans • Corn, sorghum to compare C4 vs C3 • Wheat, barley, oats vs corn to compare C3 vs C4 grasses

  5. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Total • Height • Leaf area • Root/shoot

  6. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Yield

  7. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Yield • Proteins, pigments

  8. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Yield • Proteins, pigments • Secondary products

  9. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Yield • Proteins, pigments • Secondary products • Responses to stimuli • Solar tracking • Leaf closing • Tropisms

  10. We will study effects of stresses on plants and see where it leads us • Learn about plant stress • Pick some stresses to study • Decide which plants to study and how to assay the stress effects • What to measure? • Biomass • Yield • Proteins, pigments • Secondary products • Responses to stimuli • Solar tracking • Leaf closing • Tropisms • Flowering

  11. Plant Stress Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending: anything that affects plant health Water?

  12. Plant Stress Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending: anything that affects plant health Water? Nutrients?

  13. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending: anything that affects plant health • Water? • Nutrients? • Environment? • Temp?

  14. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • pCO2?

  15. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • pCO2? • Pollution? • Ozone, other gases?

  16. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • pCO2? • Pollution? • Ozone, other gases? • Herbicides, eg Round-Up, Atrazine?

  17. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • pCO2? • Pollution? • Ozone, other gases? • Herbicides, eg Round-Up, Atrazine? • Light?

  18. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • pCO2? • Pollution? • Ozone, other gases? • Herbicides, eg Round-Up, Atrazine? • Light? • Insects and other herbivores?

  19. Plant Stress • Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending • Water? • Nutrients? • Environment? • Temp? • Pollution? • Insects and other herbivores? • Pathogens = bacteria, viruses, fungi

  20. WATER • Plants' most important chemical • most often limits productivity

  21. WATER • Constantly lose water due to PS • SPAC= Soil Plant Air Continuum • moves from soil->plant->air • Due to its special properties

  22. Water movement • Diffusion: movement of single molecules down [] due to random motion until [ ] is even • Bulk Flow: movement of groups of molecules down a pressure gradient • Independent of ∆ [ ] ! • How water moves through xylem • How water moves through soil and apoplast

  23. Water potential • Water moves to lower its potential • Depends on: • [H2O]: Ys (osmotic potential) • Pressure Yp • GravityYg Yw = Ys +Yp + Yg

  24. Water transport • Path starts at root hairs • Must take water from soil

  25. Water transport • Path starts at root hairs • Must take water from soil • Ease depends on availability & how tightly it is bound • Binding depends on particle size & chem

  26. Water transport • Availability depends on amount in soil pores • Saturation: completely full • Field capacity: amount left after gravity has drained excess • Permanent wilting point: amount where soil water potential is too negative for plants to take it up

  27. Water movement in plants Water enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermis

  28. Water movement in plants Water enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermis Must enter endodermal cell

  29. Water Transport Water enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermis Must enter endodermal cell Why flooded plants wilt!

  30. Water Transport Water enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermis Must enter endodermal cell Why flooded plants wilt! Controls solutes

  31. Water Transport Must enter endodermal cell Controls solutes Passes water & nutrients to xylem

  32. Water Transport Passes water & nutrients to xylem Ys of xylem makes root pressure

  33. Water Transport Passes water & nutrients to xylem Ysof xylem makes root pressure Causes guttation: pumping water into shoot

  34. Water Transport Passes water & nutrients to xylem Ysof xylem makes root pressure Causes guttation: pumping water into shoot Most water enters near root tips

  35. Water Transport Most water enters near root tips Xylem is dead! Pipes for moving water from root to shoot

  36. Water Transport Most water enters near root tips Xylem is dead! Pipes for moving water from root to shoot Most movement is bulk flow

  37. Water Transport • Xylem is dead! Pipes for moving water from root to shoot • Most movement is bulk flow • adhesion to cell wall helps

  38. Water Transport • Xylem is dead! Pipes for moving water from root to shoot • Most movement is bulk flow • adhesion to cell wall helps • Especially if column is broken by • cavitation (forms embolisms)

  39. Water Transport • Most movement is bulk flow • adhesion to cell wall helps • Especially if column broken by cavitation • In leaf water passes to mesophyll

  40. Water Transport • Most movement is bulk flow • adhesion to cell wall helps • Especially if column broken by cavitation • In leaf water passes to mesophyll, then to air via stomates

  41. Water Transport • In leaf water passes to mesophyll, then to air via stomates • Driving force = vapor pressure deficit (VPD) • air dryness

  42. Water Transport • In leaf water passes to mesophyll, then to air via stomates • Driving force = vapor pressure deficit (VPD) • air dryness • ∆ H2O vapor pressure [H2O(g)] • & saturated H2O vapor pressure

  43. Water Transport • In leaf water passes to mesophyll, then to air via stomates • Driving force = vapor pressure deficit (VPD) • air dryness • ∆ H2O vapor pressure [H2O(g)] • & saturated H2O vapor pressure • saturated H2O vapor pressure • varies with T, so RH depends on T

  44. Water Transport • In leaf water passes to mesophyll, then to air via stomates • Driving force = vapor pressure deficit (VPD) • air dryness • ∆ H2O vapor pressure [H2O(g)] • & saturated H2O vapor pressure • saturated H2O vapor pressure • varies with T, so RH depends on T • VPD is independent of T: says • how fast plants lose H2O at any T

  45. Water Transport • In leaf water passes to mesophyll, then to air via stomates • Driving force = vapor pressure deficit (VPD) • air dryness • Rate depends on pathway resistances

  46. Water Transport • Rate depends on pathway resistances • stomatal resistance

  47. Water Transport • Rate depends on pathway resistances • stomatal resistance • Controlled by opening/closing

  48. Water Transport • Rate depends on pathway resistances • stomatal resistance • boundary layer resistance • Influenced by leaf shape & wind

  49. Consequences of water stress Reduced productivity

  50. Consequences of water stress • Reduced productivity • Photosynthesis • Cell expansion • Wall synthesis

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