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

  • View
    215

  • Download
    3

Embed Size (px)

Text of Fruits and Vegetables. Outline This stuff is scattered in the book. –Pp. 92-101...

  • Slide 1
  • Fruits and Vegetables
  • Slide 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
  • Slide 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.
  • Slide 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). "Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad."
  • Slide 5
  • Tomato Fight! In Spain, they have an annual tomato fight
  • Slide 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.
  • Slide 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).
  • Slide 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.
  • Slide 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.
  • Slide 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.
  • Slide 11
  • Catsup Or ketchup, with lots of variant spellings Ketchup is a sauce made from tomatoes, vinegar, sugar, and various spices. It is commonly used on grilled meat and potato products. It is probably the most heavily used condiment in the US. Probable origin: a fermented fish-based sauce from the 1690s called something like koe-chiap. It spread to Malaysia, where British explorers picked up on it. The tomato-based version comes from the late 1700s/early 1800s in the US. Ketchup was popular long before eating fresh tomatoes (which were thought to be poisonous).
  • Slide 12
  • 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.
  • Slide 13
  • 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.
  • Slide 14
  • 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.
  • Slide 15
  • A Few Apple Legends Adam and Eve, the first man and woman in the Bible. The Devil tempted Eve to eat the fruit of th