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Thursday Lecture – Legumes Reading: Textbook, Chapter 6.

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Presentation on theme: "Thursday Lecture – Legumes Reading: Textbook, Chapter 6."— Presentation transcript:

1 Thursday Lecture – Legumes Reading: Textbook, Chapter 6

2 Optional Assignment - Due Tuesday March 1 Where do “baby carrots” come from? - How are they produced? [is there such a thing as a pregnant mama-carrot?!]

3 Quiz

4 1.What is a legume? 2.List two crop plants that are members of the legume family

5 Fabaceae

6 Fabaceae = Leguminosae Legume family (also called bean family or pea family)

7 Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather”

8 Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather” 19,000+ species – 3d largest

9 Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather” 19,000+ species – 3d largest 41 crop species – most of any family

10 Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather” 19,000+ species – 3d largest 41 crop species – most of any family Cereal + Legume  complete protein

11 Legume – Papilionoid flower See Fig. 6.1, 6.2, page 138

12 Legume – Papilionoid flower Banner petal See Fig. 6.1, 6.2, page 138

13 Legume – Papilionoid flower Banner petal wing See Fig. 6.1, 6.2, page 138

14 Legume – Papilionoid flower Banner petal keel wing See Fig. 6.1, 6.2, page 138

15 Legume – Papilionoid flower Banner petal keel wing See Fig. 6.1, 6.2, page 138 Stamens: 9 + 1

16 Papilionoid legumes

17

18 Other Legumes Acacia - Mimosoideae See Fig. 6.1, page 137

19 Other Legumes Acacia - MimosoideaeSenna - Caesalpinoideae See Fig. 6.1, page 137

20 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems

21 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms

22 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms How does nitrogen become available to living organisms?

23 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms How does nitrogen become available to living organisms? - reaction is called “fixation”

24 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms How does nitrogen become available to living organisms? - reaction is called “fixation” - can occur with input of energy (lightning strike)

25 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms How does nitrogen become available to living organisms? - reaction is called “fixation” - can occur with input of energy (lightning strike) - some microorganisms can carry out this reaction

26 Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems Resolution – atmospheric nitrogen is in a form (N 2 ) that is not available for chemical reactions in biological organisms How does nitrogen become available to living organisms? - reaction is called “fixation” - can occur with input of energy (lightning strike) - some microorganisms can carry out this reaction - mutualism between bacteria (Rhizobium etc.) and members of Fabaceae

27 Nitrogen-fixing Root Nodules N2 Fixing Nodules

28 Nitrogen-fixing Root Nodules Bacteria in cells Bacteria in cells N2 Fixing Nodules

29 Can we transfer N-fixation to other crops? See Box 6.1, page 141

30 Can we transfer N-fixation to other crops? See Box 6.1, page Morphological changes – development of nodule

31 Can we transfer N-fixation to other crops? See Box 6.1, page Morphological changes – development of nodule - critically important because need to exclude O 2

32 Can we transfer N-fixation to other crops? See Box 6.1, page Morphological changes – development of nodule - critically important because need to exclude O 2 2.Host/symbiont recognition

33 Can we transfer N-fixation to other crops? See Box 6.1, page Morphological changes – development of nodule - critically important because need to exclude O 2 2.Host/symbiont recognition 3.Chemical reactions to carry out N 2 fixation

34 Can we transfer N-fixation to other crops? See Box 6.1, page Morphological changes – development of nodule - critically important because need to exclude O 2 2.Host/symbiont recognition 3.Chemical reactions to carry out N 2 fixation  Multiple genes, multiple chromosome locations, not trivial

35 Nitrogen Cycle 1. nitrogen fixation nitrification denitrifying bacteria nitrogen fixing bacteria 3. nitrification atmospheric fixation 4. denitrification 2. ammonification ammonification See Fig. 6.4, page 140

36 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins)

37 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens)

38 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains

39 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains 3.High fiber levels

40 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains 3.High fiber levels 4.Isoflavones – appear to lower cholesterol levels

41 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains 3.High fiber levels 4.Isoflavones – appear to lower cholesterol levels 5.Phytoestrogens  may help relieve menopause symptoms

42 Nutritional Aspects of Legumes See Box 6.2, page Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains 3.High fiber levels 4.Isoflavones – appear to lower cholesterol levels 5.Phytoestrogens  may help relieve menopause symptoms 6.Oligosaccharides (beans, beans, the musical fruit … - see Box 6.3, page 150)

43 A Poisonous Legume Abrus precatorius – Precatory Bean Abrin – toxin, one of most toxic substances known 1 crushed seed can be fatal if ingested

44 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system

45 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering

46 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size

47 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size 4.Synchronous fruiting

48 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size 4.Synchronous fruiting 5.Loss of dormancy

49 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size 4.Synchronous fruiting 5.Loss of dormancy - question: which came first, domestication or loss of dormancy?

50 Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size 4.Synchronous fruiting 5.Loss of dormancy - question: which came first, domestication or loss of dormancy? Recent studies – no common set of “domesticated genes”

51 Major Legume Food Crops - Pulses Pulses: dried legume seeds used for food

52 Major Legume Food Crops - Pulses Pulses: dried legume seeds used for food Near East: lentils, peas, chick-peas, broad beans Far East: soybean, pigeon pea Africa: cowpeas Mexico: common bean, lima bean South America: common bean, lima bean, peanut

53 Major Legume Food Crops - Pulses Pulses: dried legume seeds used for food Near East: lentils, peas, chick-peas, broad beans Far East: soybean, pigeon pea Africa: cowpeas Mexico: common bean, lima bean South America: common bean, lima bean, peanut Commonality: Legumes – food of the poor

54 Near Eastern Pulses – 1. Lentils Lens culinaris – genus name refers to shape of seeds

55 Near Eastern Pulses – 1. Lentils Lens culinaris – genus name refers to shape of seeds

56 Near Eastern Pulses – 2. Peas Pisum sativum – used as food since ancient times (8-9,000 yrs ago) and domesticated by about 5,800 yrs ago.

57 Peas – porridge or green Pease porridge hot Pease porridge cold Pease porridge in the pot Nine days old 1600s – first use as fresh green vegetable (Holland) Specialized peas: snow peas, sugar snap peas – bred so that pods are edible in entirely, have high sugar levels

58 Near Eastern Pulses – 3. Broad Beans Vicia faba – from Mediterranean region, cultivated 8800 yrs ago. Favism – type of anemia, aggravated in susceptible individual by Vicia alkaloids

59 Near Eastern Pulses – 4. Chick- Peas

60 “cow-without-bones” - soybean Glycine max – domesticated in China >3000 yrs ago.

61 The “Cinderella Crop” U.S. – introduced as crop in 1765

62 The “Cinderella Crop” U.S. – introduced as crop in s – used for fruit rather than just forage

63 The “Cinderella Crop” U.S. – introduced as crop in s – used for fruit rather than just forage Soybeans contain a trypsin inhibitor, destroyed by heating

64 Soybean Products Oriental Foodstuffs: Miso, Tofu, Tempeh, Soy Milk, Soy Sauce Soybean Oil – widely used Soy proteins – used in many products Soy lecithin – widely used in chocolate products Non-food uses: inks, plastics, cleaners

65 Other Old World Pulses Pigeon peas, Cajanus cajan – from India Black-eyed peas (Cowpeas), Vigna unguiculata – from Africa, in U.S. considered to be southern regional specialty

66 Soybean Products Oriental Foodstuffs: Miso, Tofu, Tempeh, Soy Milk, Soy Sauce Soybean Oil – widely used Soy proteins – used in many products Soy lecithin – widely used in chocolate products Non-food uses: inks, plastics, cleaners

67 Roundup - Glyphosate Herbicide – chemical structure:

68 Roundup - Glyphosate Herbicide – chemical structure: Mode of action: blocks synthesis of certain amino acids (aromatic amino acids produced by the shikimic acid pathway)

69 Roundup - Glyphosate Herbicide – chemical structure: Mode of action: blocks synthesis of certain amino acids (aromatic amino acids produced by the shikimic acid pathway)  Toxic to most plants, but not to animals

70 Roundup - Glyphosate Herbicide – chemical structure: Mode of action: blocks synthesis of certain amino acids (aromatic amino acids produced by the shikimic acid pathway)  Toxic to most plants, but not to animals Note: can still be toxic to animals, not just the active chemical but other components of the formulation

71 Roundup - Glyphosate Herbicide – chemical structure: Mode of action: blocks synthesis of certain amino acids (aromatic amino acids produced by the shikimic acid pathway)  Toxic to most plants, but not to animals Note: can still be toxic to animals, not just the active chemical but other components of the formulation Monsanto Chemical Company – major moneymaker – while under patent protection

72 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate

73 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate Source of resistance: (1) microorganisms, have enzyme that is resistant to glyphosate

74 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate Source of resistance: (1)microorganisms, have enzyme that is resistant to glyphosate (2)Microorganisms or plants, find enzymes that alter glyphosate structure to make it harmless

75 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate Source of resistance: (1)microorganisms, have enzyme that is resistant to glyphosate (2)Microorganisms or plants, find enzymes that alter glyphosate structure to make it harmless Using (1) – Monsanto has created crops that are resistant to glyphosate “Roundup Ready”

76 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate Source of resistance: (1)microorganisms, have enzyme that is resistant to glyphosate (2)Microorganisms or plants, find enzymes that alter glyphosate structure to make it harmless Using (1) – Monsanto has created crops that are resistant to glyphosate “Roundup Ready” First Major Target: Soybeans, very successful

77 Monsanto - post-Roundup Next stage  produce genetically modified crops that are resistant to glyphosate Source of resistance: (1)microorganisms, have enzyme that is resistant to glyphosate (2)Microorganisms or plants, find enzymes that alter glyphosate structure to make it harmless Using (1) – Monsanto has created crops that are resistant to glyphosate “Roundup Ready” First Major Target: Soybeans, very successful Can spray crop after germination, kill weeds but crop little affected

78 Roundup Ready Wheat The Latest Battlefield in the “Biotech Wars”: Roundup Ready Crops: corn, soybeans, cotton None of these have major use in human consumption Roundup Ready Wheat: produced and marketed by Monsanto - major use of wheat = human food - major export crop (  Japan, Europe) Worry: if any farmers grown GM Wheat, some importers (Japan) will ban all wheat from U.S.  all farmers will lose this market

79 New World Beans – 1. Lima Beans Phaeolus lunata – Mexico to Peru, independently domesticated in the two areas. Mostly used dry. Wild plants and some cultivars contain cyanogenic glycosides – release toxic cyanide (cooking destroys compounds)

80 New World Beans – 2. Common Beans Phaseolus vulgaris – source of many types Another independent domesticate in Mexico and South America

81 Beans, Beans, Beans Selection for the variations in the seed in color and size have produced a bewildering number of variants, several of which have widespread use in our country. Kidney beanBlack beanPinto bean

82 Another New World Legume - Peanut Arachis hypogaea – peanut, ground nut, goober central South America

83 The Underground Crop

84 Forage Legumes – Sitting in the Clover Alfalfa – Medicago sativa - king of forage crops – associated with horse husbandry Clovers – Trifolium Lespedeza Sweet Clovers - Melilotus

85 Thursday Lecture – Leaf, Stem and Root Crops Reading: Textbook, Chapter 7


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