Water Potential. The physical property predicting the direction in which water will flow. Pressure

Transcription

1 Transport In Plants

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3 Water Potential The physical property predicting the direction in which water will flow Pressure water moves from high water potential to low water potential

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5 Water Potential (a) Left Side Pure Water = 0 Water Potential Right Side Negative Water Potential 0 pressure - solute (has solutes) Water moves to the right

6 Water Potential (b) Left Side Pure Water = 0 Water Potential Right Side 0 Water Potential + pressure equal to solute conc. - solute (has solutes) Water is at equilibrium

7 Water Potential (c) Left Side Pure Water = 0 Water Potential Right Side Positive Water Potential + pressure more than solute conc. - solute (has solutes) Water moves to the left

8 Water Potential (d) Left Side Pure Water and Negative Tension Right Side Negative Water Potential 0 pressure - solute (has solutes) Water moves to the left

9 Transport of Xylem Sap Pushing Xylem Root Pressure caused by active pumping of minerals into xylem : accumulation of water

10 Transport of Xylem Sap Transpiration evaporative loss of H 2 O from a plant through the stomata

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12 Transport of Xylem Sap

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15 The Control of Transpiration turgid - open flaccid - closed Potassium Ions active transport of H+ out of cell causes K+ to move in

16 Stomata Open during the day / Closed at night first light (blue light receptor) depletion of Carbon Dioxide internal clock (circadian rhythms)

17 Reducing Transpiration Small, thick leaves Thick cuticle Stomata are recessed Lose their leaves C 4 or CAM plants

18 Translocation of Phloem Sap

19 Translocation of Phloem Phloem Sap 30% sucrose, minerals, amino acids, hormones Transported in sieve-tube members leaves, tuber or bulbs Sugar sink growing roots, shoots, fruits

20 A Pressure Flow and Translocation A) Pressure is high B) Pressure is low C) Xylem recycles water D) Allows Phloem sap to flow from source to sink C B

21 Plant Nutrition

22 Uptake of Nutrients cultures used to determine which chemical elements are essential. 17 essential elements needed by all plants

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24 Soil Develops from weathered rocks Anchors plants Provides water Provides dissolved minerals

25 Soil Texture Pertains to sizes of soil particles includes the following: sands ( mm) silt ( mm) clay (less than mm)

26 Soil Composition Made up of sand, silt, clay, rocks, humus, microorganisms (bacteria, fungi, algae, protists, insects, worms, roots) Soil contains a mixture of different sized particles roughly equal amounts of sand, silt, and clay most fertile

27 The availability of soil water and minerals

28 The availability of soil water and minerals Plant takes up water not tied to hydrophilic soil particles Positively charged ions attach to soil H+ help displace minerals attached to soil Roots add H+ to the soil directly and through the release of (reacts with water to form carbonic acid)

29 The availability of soil water and minerals

30 Soil Conservation Fertilizers (Nitrogen, Phosphorus, Potassium)

31 The Nation that Destroys Its Soil Destroys Itself Franklin D. Roosevelt 1937

32 Loss of Topsoil 1930 s Due to inappropriate farming in late 1800 s and early 1900 s Wheat and cattle farming Droughts Steinbeck s Grapes of Wrath 30% of world s farmlands have reduced production due to poor soil conditions.

33 Nitrogen Fixation

34 Nitrogen Fixation Plants absorb nitrogen in the form of nitrate and ammonifying bacteria produce ammonium Ammonium is shifted to nitrate by nitrifying bacteria Plants shift nitrate back to ammonium for use

35 Nitrogen Fixation

36 Unusual Nutritional Adaptations in Plants - Epiphytes

37 Unusual Nutritional Adaptations in Plants - Mistletoe

38 Unusual Nutritional Adaptations in Plants Venus Fly Traps

39 Unusual Nutritional Adaptations in Plants Pitcher Plants

40 Unusual Nutritional Adaptations in Plants - Sundews

41 Control Systems in Plants

42 Plant Hormones Coordinates growth Coordinates development Coordinates responses to environmental stimuli

43 Plant Hormones Auxin (IAA) Cytokinins Gibberllins Abscisic Acid Ethylene Oligogaccharins Brassinosteroids

44 Auxins Stimulates stem elongation Stimulates root growth Stimulates differentiation and branching Stimulates development of fruit Stimulates apical dominance Stimulates phototropism and gravitropism

45 Auxin Control Auxin stimulates growth Auxin block on right causes cells to elongate and the plant bends left Auxin block on left causes cells to elongate the the plant bends right

46 Acid Growth Proton pump stimulated by auxin lower ph of wall H+ activates Enzyme Enzyme breaks hydrogen bonds in cellulose Wall takes up water and elongates

47 Auxin Others Promotes secondary growth by stimulating vascular cambium and secondary xylem Promotes adventitious root at the base of a cut stem Promotes fruit growth without pollination (seedless tomatoes)

48 Cytokinins Stimulates root growth Stimulates cell division and differentiation (with auxins) more cytokinin - shoot buds develop more auxin - roots develop Stimulates germination Delays Senescence

49 Gibberellins Promotes seed and bud germination Promotes stem elongation Promotes leaf growth Stimulates flowering and fruits (with auxin)

50 Abscisic Acid Slows growth Closes stomata under water stress Permits seed dormancy

51 Ethylene Promotes fruit ripening Controls Abscission (causes leaf loss)

52 Plant Movements Phototropism Gravitropism

53 Plant Movement Rapid Leaf Movement (39.27) drop in turgor pressure within pulvini sent by action potentials

54 Plant Movement Sleep Movements (39.21) cells on opposite sides of pulvinus control the movement

55 Daily and Seasonal Responses Circadian Rhythm Photoperiodism controls flowering (short-day vs. long-day) critical night length

56 Photoperiodic Control

57 Flowering Hormones Experiment indicates the presence of some type of flowering hormone

58 Phytochromes Function as photoreceptors / red (660nm) to far red (730nm) Activates kinases (regulatory proteins)

59 Red vs. Far Red Response

60 Plant Responses to Environmental Stress Water Deficit Oxygen Deprivation Salt Stress Heat Stress Cold Stress Herbivores

61 Responses to Herbivores Produce (an amino acid similar to arginine) Recruitment of predatory animals

62 Food! Why plants are important? Humans have domesticated plants for 13,000 years. of all the calories consumed by humans come from six crops: Wheat, Rice, Maize, Potatoes, Cassava, and Sweet Potatoes. Also, we use plants to feed cattle, 5-7kg to produce 1 kg of beef.

63 Pyramid of Net Productivity

64 Plants remove CO2

65 of all US Prescription Drugs contain one or more active ingredients from plants. earth s species will become extinct within the next 100 years (larger than the Permian or Cretaceous) Only 5,000 of 290,000 species have been studied. 3-4 species per hour, 27,000 per year!

66 Cinchona tree Bark contains Grows in the Andes in peru Used since the early 1600 s to treat malaria

67 Aspirin Acetylsalicylic acid or ASA Dates back to 3000 B.C. Greek Physician Hippocrates prescribed it. From and other Salicylate-rich plants (leaves and bark) Scientists at Bayer began investigating acetylsalicylic acid as a less-irritating replacement for standard common salicylate medicines. By 1899, Bayer named it this Aspirin