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Fruits and Vegetables

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Title: Fruits and Vegetables


1
Fruits and Vegetables
2
Outline
  • This stuff is scattered in the book.
  • Pp. 92-101
  • pp. 44-47
  • Tomato
  • Apple
  • Citrus
  • Brassica
  • Banana
  • Carrot
  • Onion
  • Squash and Melon
  • Tropical Fruits

3
Fruits Botanical and Popular
  • Botanically, a fruit is the ripened ovary wall.
    The ovary is part of the carpel, the innermost
    whorl of a flower, the female reproductive
    structure. The ovary contains the ovules, the
    haploid equivalent to mammalian eggs.
  • Some fruits also contain parts of the flower
    base.
  • Botanical fruits can be classified as fleshy, dry
    dehiscent, and dry indehiscent. Most of what are
    popularly called fruits are fleshy fruits.
  • The generally understood common definition of a
    fruit is sweet and aromatic fleshy plant products
    that are mainly eaten as dessert or a first
    course in a meal, and not as the main meal.
  • Thus, many fleshy fruits (in a botanical sense),
    such as tomato and cucumber, are considered
    vegetables in popular culture.
  • In botany, a vegetable is simply any plant or
    plant part.
  • In the common definition, vegetables are plant
    products eaten with the main course. In taste,
    they are salty or sour or savory, but not sweet.
    Some vegetables are botanical fruits tomatoes
    and cucumbers for example. Others are plant
    stems, leaves, and roots.

4
Legal Fruits
  • Botanically, a fruit is an ovary that has ripened
    after fertilization.
  • However, in 1883 a 10 duty was placed on all
    vegetables being imported into the US.
  • John Nix, an imported from New Jersey, argued
    that he shouldnt have to pay the duty on
    tomatoes, because botanists consider them fruits.
  • The case went all the way to the Supreme Court
    (which means at least 3 separate courts examined
    the question). In 1893, the Court ruled that for
    legal purposes, tomatoes were a vegetable, not a
    fruit.
  • Based on popular usage vegetables (including
    tomatoes) are eaten at dinner, while fruits are
    sweet and are eaten at dessert.
  • Tomatoes are the state vegetable of New Jersey.
    Ohio considers tomatoes to be the state fruit. In
    Arkansas, tomatoes are both the state vegetable
    and the state fruit (indecisive).

5
Tomato Fight!
  • In Spain, they have an annual tomato fight

6
Tomatoes
  • The tomato is a New World crop, native to the
    west coast of South America and first
    domesticated in Mexico. It is in the Solanaceae
    (nightshade) family, as are potato, chile pepper,
    tobacco, and petunia.
  • Species Solanum lycopersicum, but until
    recently Lycopersicon esculentum.
  • Brought back to Europe and to Asia (initially to
    the Phillipines) by the Spanish. It grew well in
    the Mediterranean climate and quickly caught on
    there.
  • Many varieties. A big distinction determinate
    vs. indeterminate.
  • Determinate tomatoes flower and set fruit all at
    once, and have a sfixedsize. Bush tomatoes,
    favored by commercial growers.
  • Indeterminate varieties are vine types, which
    contnue to flower and set fruit until killed by a
    frost. Favored by home growers.

7
Tomato Stories
  • Lycopersicon means wolf peach, because it is
    related to deadly nightshade. Some thought it
    could be used to generate werewolves this was an
    old German legend about nightshade, which
    Linnaeus borrowed when he named the species.
  • It was thought to be poisonous in Britain and
    America, despite being eaten in large quantities
    elsewhere.
  • In 1820, Colonel Robert Gibbon Johnson stood on
    the steps of the Salem Massachusetts courthouse,
    in front of 2000 people, and ate an entire
    bushel of tomatoes to prove that they werent
    poisonous. He survived. The local band played
    a mournful dirge as he ate, because they were
    sure he would soon die.
  • This story may not actually be true the first
    account appeared in print in 1906. It was
    dramatized in an early television series called
    You Are There, in 1949.
  • First varieties to reach Europe were yellow, not
    red. In Italy they were called pomo doro
    (golden apple). This may have been mistranslated
    into French as pommes damour (love apple).
  • Some thought they were aphrodisiacs (one of the
    eternal quests of humankind).

8
Tomato Pollination
  • The wild plants are self-incompatible they must
    be outcrossed to produce seeds and fruit.
  • To facilitate this, the female parts extend well
    beyond the flower, and the stamens stay enclosed
    within the petals.
  • The native pollinator, a small bee, didnt move
    with the plants to the Old World.
  • Selection for self-fertility was very useful.
    However, the anthers shed pollen very slowly, and
    is aided by the wind or the wing motion of
    bumblebees. In the greenhouse, a vibrator is
    used (the electric bee). This is called buzz
    pollination. The bumble bees want to eat the
    pollen tomato flowers produce very little
    nectar.

9
Growing Tomatoes
  • Tomatoes are often picked green (unripe), because
    they are firm and survive mechanical harvesting
    and shipping better.
  • Much plant breeding work went into producing
    fruit that could be harvested mechanically. One
    result was the square tomato.
  • They can be ripened with ethylene gas.
  • Ethylene is a plant hormone that stimulates
    flower opening, fruit ripening, and leaf shedding
    in many plants. It has been used since ancient
    Egyptian times to stimulate fruit ripening, by
    burning incense or by gashing figs in a closed
    room. A modern use it to put unripe fruit in a
    closed paper bag with a banana, which
    concentrates the ethylene the banana produces and
    speeds ripening. It is produced by almost all
    plants, both as part of the natural fruiting
    cycle and in response to wounding or other
    stresses.
  • Conversely, florists use ethylene inhibitors to
    extend the shelf life of cut flowers.

10
Flavr-Savr Tomatoes
  • The Flavr-Savr tomato was the first genetically
    engineered food product allowed on the US market,
    starting in 1994.
  • It was more resistant to spoiling and rotting, it
    had a longer shelf life, than normal tomatoes.
  • This was accomplished by blocking the enzyme
    polygalacturonidase, which degrades the cell
    walls and makes fruit more susceptible to fungal
    infection (which is what rotting is).
  • Didnt catch on. A big problem was that the
    starting tomatoes were not from a high quality
    strain, so yield was less than half of what good
    commercial varieties produce, and many of the
    fruits were small. Also, the fruits were more
    delicate than regular tomatoes.
  • Production ceased in 1997.

11
Apples
  • Apple trees (Malus pumila) are native to central
    Asia. The capital city of Kazakhstan, Alma-Ata,
    means father of the apple. (The city is now
    named Almaty).
  • Alexander the Great brought them back to Europe
    in 300 BC.
  • Apples are members of the Rosaceae, the rose
    family. Many other fruits also come from three
    subdivisions of this family
  • The apple subfamily also includes pears and
    quinces. The fruits are called pomes.
  • The plum subfamily includes plums, cherries,
    apricots, and peaches stone fruit, also called
    drupes.
  • The rose subfamily includes strawberry,
    raspberry, and blackberry. These are aggregate
    fruits several ovaries fused together.
  • Apples account for 60 of the temperate regions
    fruit production. It is the worlds second
    largest fruit crop, after oranges.

12
Growing Apples
  • Apples can be grown from seeds, that is, by
    sexual reproduction. However, apples are
    genetically diverse, and the process of meiosis
    ensures that every seed will be different from
    all others. This diversity is good for survival
    in nature, but it is bad for agriculture there
    is no easy way to maintain specific varieties if
    the plants are grown from seed.
  • Genetic uniformity is achieved by growing them
    vegetatively, by grafting cuttings onto the base
    of other trees. The base tree, called the
    rootstock, is from a strain that is
    disease-resistant and grows well in the region,
    but doesnt produce high quality fruits. The
    scion (the grafted plant), produces good fruits
    of a specific variety.
  • When new varieties are desired, the trees are
    grown from seed. Most new varieties appear
    spontaneously among the offspring of genetic
    crosses between different strains. Sometimes bud
    sports appear mutations that occurred in a bid,
    producing a branch on a tree that it noticeably
    different from the rest of the tree.

13
Apple Flower and Fruit
  • To produce fruits, apple flowers must be
    pollinated, usually by honeybees.
  • The apple fruit consists of an ovary with 5
    carpels fused together, surrounded by accessory
    tissue. The accessory tissue develops from the
    receptacle, the place where the flower is
    inserted into the plant stem.
  • The swollen ovary containing the seeds is the
    core, and it is separated from the accessory
    tissue by a thin brown line.
  • Most apples are picked by hand, either directly
    by the consumers or by low paid migrant workers.
  • Mechanical harvesters are often used for cider
    apples still not well developed.

14
A Few Apple Legends
  • Adam and Eve, the first man and woman in the
    Bible. The Devil tempted Eve to eat the fruit of
    the Tree of Knowledge of Good and Evil, which God
    had forbidden. She then convinced Adam to eat it
    also. For this action, God tossed them out of
    the Garden of Eden and forced them and all their
    descendants to work for a living. But, this
    fruit may have actually been an apricot it is
    not clear that apples grew anywhere near the
    Middle East when the Bible was written.
  • William Tell, the Swiss hero and crossbow expert,
    refused to bow to the hat of the Austrian
    overlord (Gessler), which had been set on a pole
    in the town square. For this crime, he was
    forced to shoot an apple off his sons head. When
    Gessler asked why he had taken out two crossbow
    bolts, Tell replied that if he had missed with
    the first one, the second arrow was meant for
    Gessler himself. This sparked a rebellion that
    led to Switzerland becoming free of the Austrian
    Empire in 1315.
  • Isaac Newton supposedly discovered gravity, or
    at least had the insight that gravity attracted
    the Moon towards the Earth in the same way that
    it attracted the apple toward the Earth, when an
    apple fell on his head.
  • And New York City is the Big Apple, the
    Beatles record company Apple Corps, and the
    Apple computer company.

15
Johnny Appleseed
  • Johnny Appleseed. John Chapman (1774-1845). He
    spread apples to western Pennsylvania, Indiana
    and Ohio.
  • He wore old ragged clothes, a pot on his head,
    and went barefoot most of the time. He was a
    vegetarian who was uncomfortable with romance,
    and he never settled down. Well-liked by all, a
    strong believer in the Swedenborg version of
    Christianity.
  • At that time, this area was part of the Old
    Northwest Territory, land west of the Appalachian
    Mountains, only lightly settled by Europeans.
  • It had been French territory, but was ceded to
    Britain in 1763.
  • The British forbade European settlement west of
    the Appalachians.
  • After the American Revolution, settlement began,
    despite armed resistance from the Native
    Americans. Resistance east of the Mississippi
    River ended in 1832, with the Blackhawk War in
    this part of Illinois. Abraham Lincoln
    participated.
  • Johnny Appleseed had a business he planted apple
    nurseries from seeds, then left a local resident
    in charge. After the trees grew, they were sold
    to the settlers.
  • Apples were not well adapted to life in America,
    so using seeds instead of grafts aided in finding
    workable varieties.

16
Cider
  • The apples planted by Johnny Appleseed were
    mostly used to make cider. We call this stuff
    hard cider today.
  • Cider is made by grinding ripe apples, then
    pressing out the juice. The juice is allowed to
    ferment for up to 3 months.
  • During this time period, cider was a common
    beverage, since water was generally contaminated.
  • Fermentation stops when the alcohol content
    reaches about 10 this kills the yeast.
  • The alcohol in cider can be concentrated to make
    applejack. The pioneer method is
    freeze-distillation. The cider was simply left
    out in winter weather. Some of the water would
    freeze, as pure water ice, leaving the alcohol
    still liquid. The colder the weather, the
    stronger the cider.
  • During Prohibition (1930s), alcohol as illegal,
    and cider got re-defined as unfermented ,
    unclarified apple juice . Sometimes called soft
    cider.

17
Citrus
  • The citrus family (Rutaceae) contains many edible
    fruits orange, grapefruit, tangerine, lemon,
    lime, and several other less well known species.
  • Not really clear how many species there are lots
    of hybrids, both ancient and modern. And, some
    "species" are clonally propagated and not
    sexually reproducing.
  • The family is native to tropical southeast Asia.
    Most varieties are very sensitive to frost and
    can only be grown where it never freezes.
  • Citrus flowers each have several carpels, and the
    fruits have a thick rind that surrounds a set of
    segments, each derived from a single carpel. The
    segments are filled with pulp.

18
Citrus History
  • The citron was widely grown in the Mediterranean
    region in Greek and Roman times.
  • Sour oranges, lemons, and limes were introduced
    by Arab traders in the Middle Ages.
  • The sweet orange, today the worlds leading fruit
    crop, was brought to Europe by Portuguese traders
    in the 1500s.
  • Citrus came to the New World with the Spanish.
  • Florida oranges are mostly grown for orange
    juice.
  • Navel oranges came from Brazil, but all US navel
    oranges are probably descended from two trees
    planted in Riverside California in 1873.

19
Citrus Fruit
  • Orange trees take 3 years to mature, and then
    bear fruit for about 20 years.
  • Citrus fruits have a thick rind that contains oil
    glands. The glands secrete a fragrant essential
    oil, which attracts animals.
  • The fruits have several fused carpels each
    orange slice is derived from a single carpel.
  • The fruits only ripen while on the tree, so they
    have to be picked when ripe, but not over-ripe.
  • Oranges on the tree are a mottled yellow and
    green color. The orange color is due to
    carotene, which is masked by chlorophyll in the
    fruit. Ethylene gas can be used to speed up the
    degradation of the chlorophyll, leading to the
    orange color.
  • Citrus fruits are high in vitamin C, which
    prevents scurvy.

20
Scurvy
  • Scurvy is a disease caused by a vitamin C
    deficiency. Vitamin C is needed to help
    synthesize collagen, the main protein in our skin
    and connective tissue.
  • A person with scurvy becomes weak and listless,
    spots form on the skin, and the mucus membranes
    bleed. In bad cases, old wounds open up and the
    teeth fall out. If not treated, it is lethal.
  • Scurvy used to be very common on long sea
    voyages. Vitamin C is found in fruits,
    vegetables, and fresh meat, but all of these were
    lacking. Sailors ate salted meat and hard
    biscuits.
  • Most animals, but not primates (or guinea pigs)
    can synthesize their own vitamin C.
  • James Lind, a surgeon in the British navy,
    described how citrus fruits could prevent and
    cure scurvy in 1753. His ideas weren't
    consistently followed until the early 1900's.
  • British sailors are called "limey" because they
    were forced to eat limes to prevent scurvy.
  • Work with guinea pigs starting in 1907 led to the
    understanding that a specific nutrient was
    lacking, and eventually to the isolation of
    vitamin C and an understanding of how it works.

21
Orange Juice
  • Most Florida oranges are converted into juice.
  • Most fruit is hand picked. But mechanical
    harvesters are improving. One method is to shake
    the tree hard enough to knock all the fruit off.
  • The ripe oranges are squeezed to extract the
    juice. Then, pulp and seeds are filtered out
    most of this ends up as animal feed. The juice
    is then concentrated by evaporation, then frozen.
    It is now "frozen concentrated orange juice".
    It gets shipped to packaging plants around the
    country, often dairies, since the packaging
    process is the same as for milk. It gets
    reconstituted by adding water, then sold to the
    consumer.
  • Some pulp is added back to produce the pulpy
    varieties favored by some consumers.
  • Frozen concentrated orange juice is a commodity
    whose futures (bets on future costs) are traded
    publicly.

22
Brassica
  • The Brassica genus is part of the mustard family.
    A wide variety of vegetable crops come from
    Brassica they are called cole crops. The
    condiment mustard also comes from members of this
    genus.
  • Members of Brassica oleracea include cabbage,
    collard greens, kale, Brussels sprouts, kohlrabi,
    broccoli, and cauliflower. The different strains
    have been bred for different traits.
  • Also, B. chinensis is bok-choi, B. campestris is
    turnip, and rutabaga is B. rapa.
  • Also, B. napus is rapeseed or canola, B. nigra is
    black mustard, B. alba is white mustard, and B.
    juncea is brown mustard.
  • The yellow color of prepared mustard (called
    American mustard in other countries) is due to
    tumeric added to the ground mustard seed.
  • The hot taste of mustard is due to an enzyme
    reaction, which produces a volatile oil when the
    ground seeds are mixed with water.

23
Brassica Plants
  • Brassica oleracea is native to the Atlantic coast
    of Europe, and was domesticated in ancient
    Greece. It is a cool weather crop.
  • Mustard flowers are yellow or white, and they
    have 4 petals.
  • The plants grow as a rosette of leaves that stays
    low to the ground. When it is mature, the plant
    "bolts". It shoots up a tall stem with the
    flowers on it.
  • Most of the Brassica vegetable crops are
    harvested before bolting. The expression "gone
    to seed", meaning decreased in quality because of
    age and neglect, comes from this phenomenon.
  • Although most Brassica vegetables are eaten
    fresh, cabbage can be converted to sauerkraut by
    shredding it and allowing it to ferment in salt
    water. Sauerkraut can be stored for a long time,
    and it retains vitamin C.

24
Brassica Breeding
  • The different varieties come from breeding for
    different traits.
  • Cabbage has lateral branches and meristems
    suppressed, so all growth goes into leaves
    produced by the terminal meristem.
  • Brussels sprouts are similar to cabbage, except
    each lateral meristem develops into a little
    head.
  • Kohlrabi is swollen stem bases.
  • Broccoli heads are immature flower buds
  • Cauliflower is a mass of stem tips, harvested
    before the flowers develop. The white color is
    due to a mutation that inhibits chlorophyll.

25
Triangle of U
  • Brassica species easily hybridize, and there is a
    set of tetraploid species derived from
    hybridization of diploids followed by doubling
    the chromosomes.
  • Chromosome numbers reflect the ancestral species.
  • First noticed by Woo Jang-choon, a Korean working
    in Japan, in 1934. By the time his name had gone
    from Korean to Japanese to English, it came out
    Nagaharu U.

26
Jack-o'-Lantern
  • Carving faces in turnips is (allegedly) an old
    tradition in the British Isles. Pumpkin carving
    is more recent (pumpkins are a New World crop).
  • An Irish legend, with many variants explains the
    origin Jack was a farmer who met up with the
    Devil one day. Jack managed to trap Satan in his
    wallet by putting a cross in there (the Devil
    lost his powers when faced with a cross). He let
    Old Scratch out only when he promised to never
    take Jack's soul. One day Jack died, and Heaven
    refused him he hadn't been a very good person.
    And, due to his bargain, Hell also refused him.
    Jack was forced to wander for eternity in the
    darkness. But, the Devil, having a sense of
    humor, tossed him an ember from Hell, which never
    goes out. Jack hollowed out a turnip, his
    favorite vegetable, and put the ember in there to
    use as a lantern. He then wandered the Earth
    endlessly, and he became know as Jack of the
    Lantern, or Jack-o'-lantern.

27
Banana
  • Genus Musa, several species. All edible bananas
    are lumped together as Musa x paradisiaca, which
    reflects their hybrid origin.
  • Two forms are popular the sweet banana we eat as
    a fruit, and the starchy plantain, which is
    cooked and eaten as a vegetable in many tropical
    countries.
  • In Asia, they are also used for beer making, and
    in general are used about like we use potatoes.
    Also, fiber for cloth and paper can be extracted.
  • Native to Southeast Asia and northern Australia.
    The wild banana was very important in
    pre-agricultural days. Probably first
    domesticated in New Guinea
  • Spread to India by 600 BC, and throughout the
    Pacific Ocean region by the Polynesians. Arab
    traders brought it to Africa about 2000 years
    ago. It flourished and spread throughout the Old
    World tropics.
  • Brought to the New World by the Portuguese in the
    1500s. Did well here too.

28
Bananas as Plants
  • The banana is a monocot, and the trunk of the
    banana tree is really tightly packed leaf bases
    arising from an underground corm.
  • The plant takes about a year to mature, starting
    from a cutting. It then flowers and sets fruit.
    The plant then dies, but the corm send out new
    stems (called suckers).
  • Fruits are picked green (unripe). Ripening is
    induced are they have been shipped to market, by
    treating them with ethylene gas.
  • Most varieties are sterile triploids, which are
    propagated vegetatively. They are seedless for
    this reason.
  • Also leaves them vulnerable to pathogens bananas
    are genetically identical, so a pathogen that
    kills one will probably be able to kill all of
    them. The banana industry is periodically
    devastated by such diseases, and much breeding
    work goes into developing resistant varieties.

29
Seedless Fruit
  • Banana fruits develop without fertilization.
    This is called parthenocarpy, and it is a common
    way of getting seedless fruit. It is due to a
    spontaneous genetic mutation, and it is found
    naturally in many plants.
  • When a plant is moved from its ancestral home to
    another part of the world, the pollinating insect
    (or bird, etc.) often doesnt came along or cant
    survive.
  • A variation on parthenocarpy some fruits need
    fertilization to develop, even though the embryos
    abort. Thus the seeds are tiny or non-existent.
  • In some species, spraying with plant hormones
    like auxin can induce parthenocarpy. This is
    commonly done with garden tomatoes.
  • This can also be done with genetic engineering.
  • Triploids are naturally sterile and seedless.
    Triploids can be propagated vegetatively, or
    triploid seeds can be produced by crossing a
    diploid with a tetraploid.

30
Banana Republics
  • Bananas rot quickly after harvest. Before steam
    ships, they were almost unknown in temperate
    climates.
  • Around 1900, refrigerated steam ships were able
    to bring them to market in America and Europe.
    This led to a vast increase in their popularity.
    At one point, bananas were cheaper than
    local-grown apples!
  • The United Fruit Company owned much of the land
    and infrastructure in several Central American
    countries, including Nicaragua, Honduras,
    Guatemala, Panama, and El Salvador.
  • The people who had formerly farmed the land were
    then hired at extremely low wages to work the
    plantations.
  • Several violent coups were engineered by United
    Fruit to remove popular governments that wanted
    to interfere. Vastly unequal distribution of
    wealth and political problems remain as a legacy
    in Central America to the present time.

31
Carrots
  • Daucus carota. Domesticated form of Queen Anne's
    Lace, a common roadside flower in late summer.
  • Umbel-shaped flower.
  • Contains carotene, the orange pigment which the
    body converts to vitamin A (retinol), the visual
    pigment.
  • The idea that eating a lot of carrots will
    improve your night vision started in England in
    World War 2, when British gunners were able to
    accurately shoot down German airplanes in the
    dark of night. This was actually because the
    British had invented radar, but they didn't want
    the Germans to know that, so the British
    government propaganda ministry started the rumor
    about carrots.
  • biennial grow as a low rosette of leaves one
    year, store food in underground taproot (which we
    eat), then send up a flower stalk the next year
    using that food.
  • We harvest it after the first growing season.
  • Diploid, grown from seed. Commercial seed is
    inbred enough to give uniform growth, but not so
    inbred as to produce inbreeding depression.

32
Carrots
  • Native to Afghanistan (it's the center of
    diversity). And other temperate parts of western
    Asia and eastern Europe.
  • In the wild, carrot roots are branched and woody
    we have selected for a single unbranched taproot.
  • When first domesticated, carrots were purple.
  • Caused by a pigment called anthocyanin, which is
    used in many flowers for red, pink, and purple
    shades. It's water soluble, producing
    purple-brown stews
  • Spontaneous mutants removed this pigment same
    taste, but no ugly color in the stew.

33
Other Carrot Family Crops
  • Carrots are members of the Apiaceae (also called
    Umbelliferaceae) family.
  • Aromatic plants with hollow stems, feathery
    leaves, and flowers like umbrellas.
  • The flowers attract parasitic wasps, which kill
    garden insects. This makes carrots good
    companions for other garden plants.
  • We also eat parsnips, which look a lot like white
    carrots. And celery is also a member of this
    family.
  • Many aromatic herbs parsley, dill, coriander,
    cilantro, cumin, fennel, caraway (seeds in rye
    bread), anise (licorice flavor).
  • Coriander is the seeds and cilantro the leaves of
    the same plant.
  • Some are quite poisonous. For example, hemlock,
    which Socrates was forced to drink for his
    execution for corrupting the morals of the young.
    Hemlock grows wild here in Illinois
  • Silphium, a giant member of this family, was used
    for birth control in ancient Roman Empire. It is
    now extinct. Grew only in a small region of the
    Mediterranean coast in Libya, and it was
    over-used.

34
Onions
  • Allium cepa.
  • Onions are in the Lily family, which is a
    monocot.
  • Onion is really a biennial or perennial the bulb
    grows in one year, then it sends up a flower
    stalk in the next year. We harvest them after
    the first season.
  • We eat the bulb underground stem base surrounded
    by fleshy leaves
  • In former times it was used as medicine for a
    large number of ailments.
  • Smell due to release of smelly sulfur compound
  • Tears when cutting come from release of sulfuric
    acid and related compounds.
  • Can be grown from seed or from seed sets, which
    are small onions grown from seed using a seed
    set gives them a head start so they get bigger
    during the growing season.

35
Onions
  • Wild onions are edible it was probably harvested
    from the wild long before it was cultivated.
  • Cultivated from early times in both Egypt and
    China by 3000 BC. It stores well.
  • Wild relatives in Central Asia, so that's
    probably where it was first domesticated, but no
    direct proof of this.
  • We tend to use onion as a food flavoring, but it
    can also be eaten as a vegetable
  • unattributed odd "fact" the people who built in
    Pyramids in Egypt may have lived on radishes and
    onions. Wikipedia links to a food/garden site
    that just says it out of the blue.
  • Onion (as Allium) is a garden flower blue
    puffball heads. It's a perennial.
  • Other relatives garlic, leek, shallot, chives.
  • Garlic usage has greatly increased in the US in
    recent years people like spicier food.

36
Squashes and Melons
  • Both are members of the Curcurbitaceae, the
    cucumber family. Squashes domesticated in New
    World, melons in Old World Africa and South East
    Asia independently. Very early domestication.
  • All are creeping vines with separate male and
    female flowers on the same plant. We eat the
    fruits, which have multiple seeds surrounded by a
    fleshy fruit that has a hard rind.
  • Originally grown for the seeds wild relatives
    can be eaten but the flesh is bitter. Seeds high
    in sulfur-containing amino acids. Pumpkin seeds
    are still widely eaten.
  • Hard rind makes them easy to store, and soft
    flesh works well as a water source in the desert.

37
Squash
  • Squash four cultivated species in the genus
    Curcurbita, with lots of variation in form within
    each species, and overlapping between species.
    E.g., "winter squash" and "pumpkin" can be any
    one of the four.
  • Types pumpkins, zucchini, butternut, turban,
    acorn, summer, plus others.
  • Squash was gown along with maize and beans in
    ancient Mexico. The vine provides a ground cover
    that suppresses weeds, the beans fertilize the
    soil by fixing nitrogen, and the maize provides a
    living pole for the beans to grow on. This is
    called the three sisters method.
  • Giant pumpkins are Curcurbita maxima. Current
    record (2010) 1810.5 pounds. Its been going up
    by 50 pounds a year or so.

38
Melons
  • Watermelon are from west Africa. Eaten in
    ancient Egypt by 2000 BC. King Tutankhamen's
    tomb contained many watermelon seeds. Grown in
    China by 1000 AD.
  • Cantaloupe and honeydew melons are from central
    Asia. Also cucumbers same species.
  • Cucumbers can be turned into pickles by soaking
    them in salt water (brine) at low pH (acid).
    Sometimes vinegar is added, along with spices
    such as dill and garlic. A bacterial fermentation
    process turns them sour. Originally used for
    food preservation, now mostly for flavor. Other
    vegetables can be pickled.
  • Playwright Neil Simon once said, Words with a k
    in it are funny. Alka-Seltzer is funny. Chicken
    is funny. Pickle is funny....
  • Loofah is a species of curcurbit whose fruit is
    allowed to partially rot, leaving a network of
    fibrous tissue. This is used for scrubbing your
    body the loofah sponge. The fruit can also be
    eaten as a vegetable before it matures.

39
Calabash
  • The calabash, or bottle gourd, is another
    curcurbit of note. It was one of the first
    domesticated plants.
  • It is grown for use as a container, not for food.
    When dried out, the woody rind in strong and
    waterproof.
  • Also used as a body for musical instruments,
    stringed, rattles and drums
  • and often highly decorated.
  • It also has been used for smoking pipe bowls
    Sherlock Holmes (a fictional character) smoked a
    calabash pipe.

40
Calabash Origins
  • The calabash originated in the dry warm areas of
    southern Africa, where there a wild relatives.
  • The wild species have thin rinds the cultivated
    varieties have clearly been selected for thick
    waterproof rinds.
  • However, the calabash reached Asia very early it
    has been found at archeological sites that are
    8000 years old.
  • Today Asian and African varieties are relatively
    distinct.
  • The calabash was also grown in the New World 8000
    years ago, long before Columbus. This leads to.
    another ancient contact story how did it get to
    the Americas?
  • The main theory for the past 150 years it
    rafted across the Atlantic Ocean from Africa in a
    mass of vegetation without human assistance. The
    rind is quite waterproof and the seeds are
    capable of germinating after a long dormancy
    period.
  • Alternative a boatload of African fishermen
    blown off course and landing in South America.
  • Much less likely by boat across the Pacific
    Ocean. Polynesia was settled much later between
    3000 and 1000 years ago.

41
More Calabash Origins
  • Recent genetic and archeological study shows that
    the pre-Columbian calabash in America came from
    Asia. (D.L. Erickson et al., 2005, Proc. Nat.
    Acad. Sci USA 10218315-18320)
  • This suggests it came over the Bering Land Bridge
    around 12,000 years ago with the original
    inhabitants of the New World, the Paleoindians.
    Sea level was much lower at that time, due to the
    Ice Age glaciers locking up much water.
  • They were hunter-gatherers settled agriculture
    hadnt been invented yet. They also brought the
    dog to the New World.
  • Dates from carbon-14 decay. It gets into plants
    from carbon dioxide in the atmosphere. When the
    plant dies, no new C-14 is added, and it slowly
    decays into nitrogen. So, the amount of C-14
    left is proportional to how long ago the plant
    died.
  • Calibrated by counting tree rings. In some
    places, tree ring chronologies go back 10,000
    years.

42
Genetic Evidence
  • The scientists involved here wanted to compare
    DNA from New World archeological specimens to
    plants grown today in Africa and Asia.
  • They collected calabashes from traditional
    farmers in both Africa and Asia, to avoid getting
    seeds form modern cultivars.
  • Also needed very careful treatment of
    archeological material to avoid contaminating
    ancient DNA with modern DNA.
  • Looking for differences in the DNA that would
    reliably distinguish between Asian and African
    varieties. There are a few regions in the genome
    that are easy to analyze and known to be quite
    variable. Mostly, the Asian and African varieties
    proved to be very similar in their DNA.
  • Found three good differences in the chloroplast
    DNA. All modern Asian varieties had one allele
    and all modern African varieties had the other
    allele.
  • Results of the 12 archeological samples, only 10
    produced any data. Of these, the nine that had
    pre-Columbian dates all had the Asian DNA
    markers.
  • The one with a post-Columbian date had the
    African markers Columbus brought the African
    variety to the New World, and it has mostly
    replaced the Asian variety.
  • So, there is strong evidence that the
    pre-Columbian calabash came from Asia. How it
    got there is not proven the Bering Land Bridge
    theory fits well with other knowledge of how the
    New World was settled.

43
Calabash Data
44
Tropical Fruits
  • Pineapple, date, figs, coconut, avocado,
    pomegranate, mango, papaya.
  • Plus lots of others that are very tasty but don't
    ship well, so are only eaten locally.
  • Not to mention nuts, which we haven't even
    touched on.
  • The mind boggles
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