1. Chapter 10 – Transport in Plants

2. Transport in plants  Water and mineral nutrients must be absorbed by the roots and transported throughout the plant  Sugars must be transported from site of production, throughout the plant, and stored

3. Cellular transport mechanisms

4. Osmotic potential, solutes, and water movement

5. Water potential influences water movement  Water potential (Ψ) of a cell: Ψ cell = Ψ Ρ + Ψ Ο Ρ = pressure potential Ο = osmotic (solute) potential

6. Ψ p - Pressure potential (turgor) Low Ψ p High Ψ p

7. Ψ Ο – Osmotic (Solute) potential  Pure water Ψ Ο = 0  All solutions, Ψ Ο < 0  As solute concentration increases, Ψ cell …

8. Water movement in plants  Movement from high Ψ cell to low Ψ cell  Occurs in the xylem  Involves adhesion, cohesion, and pressure

9. Adhesion and cohesion

10. Water transport

11. Tension-cohesion theory explains xylem transport  Water is drawn up the plant by transpiration of water from stomata

12. A water potential gradient creates tension

13. low ψ Transpiration creates tension higher ψ cohesion higher ψ lower ψ higher ψ lower ψ higher ψ highest ψ lower ψ

15. Water transport animation

16. Transpiration & water transport

17. Importance of stomata  Regulate transpiration rate –Controls rate of water uptake  Water required for photosynthesis  Water required to maintain turgor pressure  Influences nutrient uptake  Regulate gas exchange –CO 2 required for photosynthesis

18. Turgid guard cells open stomata

19. Guard cells & osmotic potential

20. Transpiration & photosynthesis

21. Ψ and transpiration rate  In terms of ψ, can you explain how transpiration rate is influenced by: –Atmospheric humidity? –Wind? –Air temperature? –Light intensity?

23. Which of the following explains why water moves into the root from the soil? 1. The water potential of the root is lower than the water potential of the soil 2. The roots exist in a hypertonic environment 3. The pressure potential of the soil forces water into the root 4. Water is actively transported into the root 5. The soil has a higher solute concentration than the roots, causing water to diffuse into the roots

24. Stomata close when 1. Photosynthesis lowers CO 2 concentrations in the leaves 2. Potassium ions are pumped into guard cells 3. Abscisic acid levels increase 4. Guard cells become turgid 5. All of these occur

25. A guard cell with a high internal concentration of K + 1. Is in a hypertonic condition 2. Has a low water potential relative to outside of the cell 3. Has a higher water potential than outside the cell 4. Both 1 and 2 5. Both 2 and 3

26. Water transport

27. Sugar transport

28. Source to sink sugar transport

29. Pressure-flow hypothesis explains sugar transport

30. Phloem loading

31. Sugar transport can be explained by water potential

32. Transport in plants  Water and mineral nutrients are absorbed by the roots and transported throughout the plant by tension-cohesion  Sugars are transported from site of production (source), throughout the plant, and stored (sinks) by pressure-flow

33. Mineral nutrition & uptake

34. Soils and plant nutrition  14 essential mineral nutrients –N,P,K,S,Ca,Mg,Fe,Cl,Mn,B,Zn,Cu,Mo,Ni  3 essential non-mineral nutrients –C,H,O –What makes these nutrients essential?

35. Magnesium and photosynthesis

36. Nitrogen and amino acids

37. Nitrogen, phosphorus & DNA

38. Potassium and cell function

39. Macronutrients vs. micronutrients

40. Fertilizers  Fertilizer analysis (N-P-K)  Analysis varies depending on growth objectives

43. How can essential elements be determined?

44. Hydroponics

46. Recreational hydroponics  Home hydroponics systems Home hydroponics systems

47. A soil profile  Soil composition –Sand, silt, clay –Humus –Microorganisms –Animals

48. Mineral nutrients exist as ions

49. Cation exchange allows mineral ions to be absorbed by roots

50. Cation exchange and H +

51. Mineral nutrient transport

53. How does cation exchange affect soil pH?  Raising soil pH with lime Ca(OH) 2 + 2H +  Ca 2+ + 2H 2 O

54. Soil pH and mineral nutrition Different types of plants have different soil pH requirements (ex. truffles, filbert trees, and alkaline soils)

55. Which of the following statements concerning plant nutrition is/are true? 1. Macronutrients are large elements and micronutrients are small elements 2. Macronutrients are essential to plant growth and micronutrients are not essential 3. Macronutrients are absorbed from the atmosphere and micronutrients are absorbed from the soil 4. All of these are true 5. None of these are true

56. Cation exchange 1. Occurs when plants release O 2 and absorb CO 2 through their stomata 2. Involves plants releasing Ca 2+ into the soil in order to absorb H + ions 3. Involves the release of H + ions from roots to displace mineral nutrient ions from soil particles 4. Allows plant roots to absorb C, H, and O through their roots by converting these atoms to cations