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Thursday Lecture – Legumes Reading: Textbook, Chapter 6
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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?!]
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Quiz
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1.What is a legume? 2.List two crop plants that are members of the legume family
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Fabaceae
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Fabaceae = Leguminosae Legume family (also called bean family or pea family)
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Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather”
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Fabaceae = Leguminosae Legume family (also called bean family or pea family) “legere” – Latin for “too gather” 19,000+ species – 3d largest
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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
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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
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Legume – Papilionoid flower See Fig. 6.1, 6.2, page 138
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Legume – Papilionoid flower Banner petal See Fig. 6.1, 6.2, page 138
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Legume – Papilionoid flower Banner petal wing See Fig. 6.1, 6.2, page 138
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Legume – Papilionoid flower Banner petal keel wing See Fig. 6.1, 6.2, page 138
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Legume – Papilionoid flower Banner petal keel wing See Fig. 6.1, 6.2, page 138 Stamens: 9 + 1
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Papilionoid legumes
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Other Legumes Acacia - Mimosoideae See Fig. 6.1, page 137
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Other Legumes Acacia - MimosoideaeSenna - Caesalpinoideae See Fig. 6.1, page 137
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Nitrogen Fixation Paradox – atmosphere is 80% nitrogen (N) yet N is a limiting factor for plant growth in almost all ecosystems
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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
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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?
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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”
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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)
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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
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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
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Nitrogen-fixing Root Nodules N2 Fixing Nodules
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Nitrogen-fixing Root Nodules Bacteria in cells Bacteria in cells N2 Fixing Nodules
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Can we transfer N-fixation to other crops? See Box 6.1, page 141
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Can we transfer N-fixation to other crops? See Box 6.1, page 141 1.Morphological changes – development of nodule
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Can we transfer N-fixation to other crops? See Box 6.1, page 141 1.Morphological changes – development of nodule - critically important because need to exclude O 2
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Can we transfer N-fixation to other crops? See Box 6.1, page 141 1.Morphological changes – development of nodule - critically important because need to exclude O 2 2.Host/symbiont recognition
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Can we transfer N-fixation to other crops? See Box 6.1, page 141 1.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
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Can we transfer N-fixation to other crops? See Box 6.1, page 141 1.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
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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
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins)
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens)
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.Legumes produce many N-containing compounds - nutritious foods (proteins, vitamins) - poisons (alkaloids, cyanogens) 2.Amino acid content of proteins – complements grains
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.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
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.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
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.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
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Nutritional Aspects of Legumes See Box 6.2, page 142 1.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)
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A Poisonous Legume Abrus precatorius – Precatory Bean Abrin – toxin, one of most toxic substances known 1 crushed seed can be fatal if ingested
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Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system
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Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering
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Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size
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Legumes – Changes Under Domestication 1.Annual habit, selfing breeding system 2.Less seed scattering 3.Greater seed size 4.Synchronous fruiting
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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
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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?
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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”
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Major Legume Food Crops - Pulses Pulses: dried legume seeds used for food
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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
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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
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Near Eastern Pulses – 1. Lentils Lens culinaris – genus name refers to shape of seeds
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Near Eastern Pulses – 1. Lentils Lens culinaris – genus name refers to shape of seeds
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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.
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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
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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
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Near Eastern Pulses – 4. Chick- Peas
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“cow-without-bones” - soybean Glycine max – domesticated in China >3000 yrs ago.
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The “Cinderella Crop” U.S. – introduced as crop in 1765
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The “Cinderella Crop” U.S. – introduced as crop in 1765 1920s – used for fruit rather than just forage
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The “Cinderella Crop” U.S. – introduced as crop in 1765 1920s – used for fruit rather than just forage Soybeans contain a trypsin inhibitor, destroyed by heating
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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
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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
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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
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Roundup - Glyphosate Herbicide – chemical structure:
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Roundup - Glyphosate Herbicide – chemical structure: Mode of action: blocks synthesis of certain amino acids (aromatic amino acids produced by the shikimic acid pathway)
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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
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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
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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
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Monsanto - post-Roundup Next stage produce genetically modified crops that are resistant to glyphosate
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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
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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
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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”
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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
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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
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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
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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)
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New World Beans – 2. Common Beans Phaseolus vulgaris – source of many types Another independent domesticate in Mexico and South America
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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
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Another New World Legume - Peanut Arachis hypogaea – peanut, ground nut, goober central South America
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The Underground Crop
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Forage Legumes – Sitting in the Clover Alfalfa – Medicago sativa - king of forage crops – associated with horse husbandry Clovers – Trifolium Lespedeza Sweet Clovers - Melilotus
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Thursday Lecture – Leaf, Stem and Root Crops Reading: Textbook, Chapter 7
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