1. Translocation of Photosynthate (Photoassimilate)
No Known Pumping Organ
Two Separate Conducting Tissues:
Xylem
Phloem

2. Translocation of Photosynthate
Two Separate Conducting Tissues:
Xylem
tracheids
vessel elements
Phloem - photosynthate (photoassimilate)
sieve tube elements
companion cells (nucleus)

4. Dicot

5. Stem X-Section -Herbaceous Dicot

6. Phloem Tissue
Parenchyma
fibers

7. Phloem Cytoplasmic connections P-Proteins (slime)
Callus Plugs (carbohydrate)

9. Seive Plate - Callose Plugs

10. Phloem Sap - Sugars * Sucrose C12H22O11
Glucose - some Lilies, Liliaceae
Mannitol & Sorbitol (sugar alcohols) - Rosaceae
Raffinose, Stachyose, Verbascose -Cucubitaceae

11. Chemical Interconversions
PCR Cycle – 1st hexose phosphate = fructose-6-phosphate
phosphoglucomutase
F-6-P  G-6-P  G-1-P
G-1-P starting pt. for synthesis of sucrose, starch, cellulose

12. Chemical Interconversions
G-1-P starting pt. for synthesis of sucrose, starch, cellulose
UTP + G-1-P  UDPG (uridine diglucophosphate) + P P
UDPG + F-6-P  G-F-6-P (sucrose-6-phosphate)
G-F-6-P  G-F (sucrose) + P

14. Carbon Allocation Starch (storage) Sugars (translocation)
Sugarbeets and Sugarcane - store sucrose

15. Chemical Interconversion
Starch Synthesis:
glucose polymer – amylose 1-4 linkages Alpha
amylopectin 1-4 and 1-6 Beta linkages
Build Up
ATP + G-1-P  ADPG (adenosine diphosphoglucose) + P
ADGP + glucose  G-G… + ADP

17. Chemical Interconversion
Starch Synthesis:
Break Down
G-G-G… + P  G-P

18. Chemical Interconversions
Cellulose
Most abundant carbohydrate on earth (cell walls)
Formed like starch (glucose donor is a different nucleotide sugar- GDPG)
Beta linkages between all glucose units
Seldom broken down in nature
Microrganisms - cellulase

19. Phloem Sap - Non-Sugars
Phytohormones -
Amino Acids (Glutamic and Aspartic Acids) & Other Organic Acids
Minerals - Anions (Phosphate, Sulfate, Chloride, etc.) & Cations (Potassium) ?

20. Aphids Use Stylus to Extract Phloem Sap

21. Carbon Distribution
Source --> Sink

22. Sinks Under Varying CO2 Levels

23. Munch Pressure-Flow Hypothesis E
Munch Pressure-Flow Hypothesis E. Munch 1930 A Mechanism for Moving Phloem Sap from Source to Sink within the Plant
1. Sugars (solute) accumulate in leaves and other photosynthetic organs. SOURCE
2. Sugars are pumped into phloem of photosynthetic organ by active transport. LOADING

24. Munch Pressure-Flow Hypothesis E
Munch Pressure-Flow Hypothesis E. Munch 1930 A Mechanism for Moving Phloem Sap from Source to Sink within the Plant
1. Sugars (solute) accumulate in leaves and other photosynthetic organs. SOURCE
2. Sugars are pumped into phloem of photosynthetic organ by active transport. LOADING

25. Phloem Loading

27. Munch Pressure-Flow Hypothesis E
Munch Pressure-Flow Hypothesis E. Munch 1930 A Mechanism for Moving Phloem Sap from Source to Sink within the Plant
1. Sugars (solute) accumulate in leaves and other photosynthetic organs. SOURCE
2. Sugars are pumped into phloem of photosynthetic organ by active transport. LOADING
3. Loading of phloem causes phloem sap to take on water by osmosis. HYDROSTATIC PRESSURE

28. Munch Pressure-Flow Hypothesis E
Munch Pressure-Flow Hypothesis E. Munch 1930 A Mechanism for Moving Phloem Sap from Source to Sink within the Plant
1. Sugars (solutes) accumulate in leaves and other photosynthetic organs. SOURCE
2. Sugars are pumped into phloem of photosynthetic organ by active transport. LOADING
3. Loading of phloem causes phloem sap to take on water by osmosis. HYDROSTATIC PRESSURE
4. The Phloem sap is pushed through the seive tube column to a SINK area of low solute concentration. (root, bud, grain, bulb, etc.) Sap is pulled out by active transport or stored as starch. UNLOADING
5. Sap continues to flow toward the sink as long as sugars (solutes) do not accumulate in the phloem.

29. Phloem Unloading

30. Munch Pressure Flow Hypothesis is supported by the evidence.
Known rates of movement 100cm/hr., squash 290 cm/hr.
Living cells are necessary (active transport)

31. Direction of Phloem Sap Movement (Radioactive Feeding Techniques) Distribution of Photosynthate
Sap moves in both directions (up & down) - in separate phloem ducts.

32. Direction of Phloem Sap Movement (Radioactive Feeding Techniques) Distribution of Photosynthate
Sap moves in both directions (up & down) - in separate phloem ducts.
Very little tangential movement on maturre stem.
Growth is decreased on defoliated side.
Feed radioactive CO2 to one side - very little radioactive photosynthate shows up on other side.

33. Direction of Phloem Sap Movement (Radioactive Feeding Techniques) Distribution of Photosynthate
Sap moves in both directions (up & down) - in separate phloem ducts.
Very little tangential movement on maturre stem.
Growth is decreased on defoliated side.
Feed radioactive CO2 to one side - very little radioactive photosynthate shows up on other side.
More tangential movement among young leaves.

34. Between Phloem and Xylem
Some exchange - mostly to remove mineral from senescent leaves (source to sink).

35. Factors Affecting the Translocation of Sap
Temperature
Increased temperature – increased loading & unloading optimum degrees C
Chilling Sensitive Plants (most)
Chilling Tolerant Plants (beets)
Can acclimate translocation of photosynthate to increasingly cold conditions

36. Factors Affecting the Translocation of Sap
Light
In the dark root translocation of photosynthate is favored over stem translocation.
At least one study shows that the translocation of sap in the stem was increased by BLUE and RED light.

37. Factors Affecting the Translocation of Sap
Hormones
Both cell division (cytokinins) and cell elongation (auxins) creates sinks – absorbs sap.
Bud break
Increased G A, decreased ABA

38. Development of Tissues of Transport and Translocation

39. Development of Tissues of Transport and Translocation

40. Development of Tissues of Transport and Translocation

41. Development of Tissues of Transport and Translocation

43. Consequences of Ambient Conditions on Tree Growth Rings

44. Dormant Woody Stem

47. Cellular Respiration
Oxidation of Organic Molecules - production of ATP
Intermediates (carbon skeletons) produced
Aerobic:
C6H12O6 --> Pyruvate (C6) + O2 --> CO2 + H2O + ATPs
Anaerobic:
C6H12O6 --> Pyruvate (C6) --> Ethanol (C2)+ CO2
+ ATPs

48. Cellular Respiration - 3 Stages
1. Glycolysis - Ebden Myerhoff Parnas Pathway
(in the cytosol; no O2 required)
Glucose ATP
C6H12O > Glucose-6-Phosphate -->
> Fructose-6-Phosphate (C6) ---->
- ATP
> Fructose-1,6-Diphosphate (C6) -->
Dihydroxyacetone <--> Phosphoglyceraldehyde (C3)
Phosphate (C3) >

49. Glycolysis - EMPP (Anaerobic)
2 ATPs Used
4 ATPs Gained + 2 NADH2s
Pyruvic Acid (C3)
intermediates

50. Fate of Pyruvate

51. If Aerobic:
1. Pyruvate (C3) is further broken down in the KREBS CITRIC ACID CYCLE (in mitochondrion)
2. NADH2s are used to build ATPs in the ELECTRON TRANSPORT CHAIN (ETC)

52. Krebs Citric Acid Cycle

53. Krebs Citric Acid Cycle

54. Electron Transport Chain

55. Energy Budget Glycolysis: 2 ATPs net gain from 1 glucose Anaerobic
Krebs Cycle & ETC: 36 ATPs net gain from 1 glucose
Aerobic: 38 ATPs

56. Cyanide Resistant Respiration Many plants have been discovered to have a branch point in the ETC.
After Coenzyme Q
- Only 1 ATP produced
- H2O2 produced
+ More heat produced
+ in plant tissues.
+ Fruit ripening
+ Rids excess NADH2.
Krebs Cycle continues
to produce intermediates.

57. Cyanide Resistant Respiration Many plants have been discovered to have a branch point in the ETC.
After Coenzyme Q
- Only 1 ATP produced
- H2O2 produced
+ More heat produced
+ in plant tissues.
+ Fruit ripening
+ Rids excess NADH2.
Krebs Cycle continues
to produce intermediates.

58. Oxidative Pentose Phosphate Pathway
NADPH2 for PCR Cycle and
Biosyntheses
Biosynthesis of Nucleic Acids,
RuBP
Up to 20% of Glucose may use
OPPP rather than Glycolysis.

59. Lipid Catabolism - Glycolate Cycle

60. Respiratory Rate and Age

61. Photosynthesis and Respiration