Poisonous Hemlock
Poisonous Hemlock
The Legumes (Nodulation)
Last time: Agriculture and the Grains, Wheat, Maize and Rice.
Feb 19, Monday – in one week is Exam I
Carrot family – Apiaceae, Also know as the parsley family Umbelliferae.
300 genera & ~ 3000 Species: ¼ of genera native to U.S.
Contains important food plants: Carrots, parsnips, celery Coriander seeds, cilantro, Caraway, parsley & dill – also poison hemlock.
Description: A tall, usually much – branched, imposing plant with purple-spotted stems, compound leaves, and small compound umbels of white Flowers.
Height: Two to ten feet.
Leaves: Pinnate compound.
Flowering: 2mm long, five petals, compound umbel.
Habitat: Waste places, weedy areas, and woodland borders.
Range: Throughout East, except Newfoundland & Arctic, also in much of Western U.S.
Toxin is a volatile oily compound.
Coniine was the first alkaloid synthesized in the laboratory.
Piperidine structure: nitrogen in a six-member ring.
Socrates drank a potent solution of poisonous hemlock 399 BC
The young leaves and fresh seeds contain the highest alkaloid content.
Used by Greek and Arab physicians for a variety of problems including arthritis. It was not always effective …caused death… as the difference btw. a therapeutic and a toxic amount or measure can be very slight..
No plant extract should be consumed by unqualified humans (practitioners)!
A current issue with poisonous hemlock is: prevent livestock from consuming poisonous hemlock while grazing (in large open rangelands)!
• 399 BC poisoning of Socrates by poisonous hemlock.
• Active constituents are of the piperidine alkaloids family
• ~all related to coniine alkaloids all of very simple chemical structures.
Synonymous with pod, the fruit produced
Seeds are inside the pod or legume
Examples include: Peas, Soybean, Beans, Clover, Alfalfa & Peanuts
With N-fixing root nodules
Major nitrogen fixers with symbiotic bacteria in root modifications called root nodules – fixes nitrogen from air and makes it available to plant
Flowers are irregular, bilaterally symmetric
Pollination is by bees (hive decline, pesticide- pathogen interactions)
Fruit is a pod or legume, a long fruit with two rows of seeds, easily splits on two seams, two rows of seeds; example, peas in a pod.
Nitrogen fixation was discovered in legumes, due to symbiotic association of Rhizobium species of bacteria that inhabit nodules on roots
Bacteria give plant nitrogen and plant gives bacteria carbon
which reacts with water to form NH4+
Performed biologically by:
Nitrogen-fixing bacteria and cyanobacteria
Bacteria may be free-living in soil or in symbiosis with plant
Legumes are the only agricultural families that have symbiotic N-fixing bacteria (woody)
S. fredii Glycine (Soybean), Cowpea
S. sp. NGR234 Broad host range: many genera of legumes
Rhizobium leguminosarum biovar trifolii
Trifolium (clover)
Mesorhizobium loti Lotus (trefoil), Lupinus (lupine)
Bradyrhizobium japonicum Glycine max
two way chemical-mediated communication
Stage or symbiosis
Rhizobium genes
Known or proposed function
Host plant signal nodD, nolR Activate or repress transcription of nod box promoters
Nodule formation, Host recognition
exo, lps, ndv Enzymatic synthesis of Nod factors
Differentiation Bacteroid metabol.
bacC dct genes
Signal import / export Import of dicarboxylic acids
Regulation of N- fixing genes , N- fixing
fixL, fixJ, nifA, fixK; nifHDK
Response to O2; control nif promoters; Nitrogenase & cofactors
Bacteroids
Bacterium
Start here
Soybean Nodulated
Soybean not Nodulated
Bean: Phaseolus vulgare: Green bean and others – native to Mexico and the Andes (S.A.)
Rich in protein and also some carbohydrates Intestinal gas – alleviate gas production in us by
long cooking time, treatment of cooked beans with enzyme, and plant breeding to eliminate complex carbohydrates
Red kidney, black, kidney, mung, adzuki, black-eye pea, fava, broad
Rich in protein and carbohydrates
Immature pod also eaten, as snow peas or sugar snap peas
Peas grown in U.S. as field pea for livestock, a garden pea and as an edible-podded pea
Rich in oil and protein Unusual growth characteristics: after fertilization, the flower stalk dips downward and grows into the ground where the pod matures to produce peanuts – also called ground nuts
Uses: Half of U.S. crop for peanut butter, rest for snack food, candy, peanut oil
Oil used for cooking oil, salad dressing, margarine, shortening, mayonnaise
Oilcake is rich in protein, used for animal feed, used as meat substitute for humans
Traditional uses in the Orient:
Soy sauce – fermented soybeans and grain Tofu – soy milk curds Miso – fermented soybean & rice past in Japan Tempeh – fermented soy cake in Indonesia Soybeans also eaten as sprouts Widely used in health food
Industrial uses: Oil can be used as diesel fuel, or made into plastic, paint, ink, soap
A major crop in the U.S. with production increasing rapidly with greater yields
Medicago sativa – Alfalfa – some 20 million acres planted in U.S.
Trifolium spp. – True clovers – many species. Red & white clovers
Vicia spp. Vetches planted for hay and erosion control
•Ginger the root spice
•Starchy Staples
Exam I – Next Monday (Feb 19)
PMT: Class 9
