Welcome to an overview of what Economic Botany has to offer.
It will be a distance learning course this spring 2000, so below are highlights of what I plan
to be doing in the TopClass format
LECTURE 4 HIGHLIGHTS FOR BIOLOGY 03074, ECONOMIC BOTANY: CROPS; LEGUMES
Text for both editions: Chs. 10, 13.
Possible web site: http://www.life.umd.edu/classroom/bsci124/lec26.html
(covers legumes and starchy crops, including many links for Irish potato famine)
Fabaceae (Leguminosae): the bean or legume family. Generally 5-merous, unicarpellate flowers that have a legume or pod for a fruit. The seeds contain two prominent, food-storing cotyledons. Examples: Mimosa, mimosa, sensitive plant; Arachis, peanut; Pisum, pea; Phaseolus, beans.
Nitrogen cycle: nitrogen is essential for protein and for the nucleic acids that make up DNA. Even though about 80% of the atmosphere is nitrogen gas (N2), it takes a lot of energy to break those stable NºN bonds and put nitrogen into a situation where it can be used. The major step is nitrogen fixation , involving the conversion of nitrogen gas (N2) to ammonia (NH3) (reduction for you chemistry fans). This can be done by a nitrogenase enzyme that is carried by a bacterium (typically Rhizobium) in legume nodules.
Pulses: dried legume seeds used for human food. Legume seeds are easily harvested and have low water contents, so they store for a long time. Beans a good source of proteins:"poor man's meat."
Peanuts, Arachis hypogea. Originally domesticated about 4000 BC in South America. After pollination, the flower stalk aims down and pushes the fruit into soil. Peanut in US grown in light sandy soils in the South. G. W. Carver highlighted versatility of peanut, trying to use it as a crop to replenish Southern soils exhausted from cotton monoculture.
Soybeans, Glycine max. From Orient, where it was popular for centuries, soybean was brought to Germany in 1600s. Only in 1920s was there real interest in US for crop (now world's leading producer). Does well in our Corn Belt: warm temperate climates with moderate amounts of rainfall. Typically soybean is modified from seed form: e.g., tofu or curds from soy milk.
A major aspect towards consideration of sustainable agriculture is towards growing more legumes in with grasses to replenish the soil.
Alfalfa, Medicago sativa. Romans recognized it as good horse feed, Spaniards brought it to US. Alfalfa is a perennial grown from seed, used as pasture crop or harvested from hay.
Possible"new" legumes that might have future uses include Leucaena leucocephala: a fast growing tropical tree. Can grow up to 8 m/year. Good for firewood, which is in short supply in developing countries.
HUMAN NUTRITIONAL NEEDS. Macronutrients of carbohydrates, proteins, lipids vs.
micronutrients of vitamins, minerals.
1) carbohydrates, such as sugars, that are readily used in cell respiration to generate energy
2) proteins are usually used to become the building blocks for body materials, e.g., muscle, hair.
3) lipids, e.g., fats and oils, are also energy sources for cell respiration
In contrast, the micronutrients are organic vitamins, inorganic minerals. Vitamins are coenzymes that help enzymes function, or are involved in compound synthesis.
Two main diseases of malnutrition seen in developing countries: marasmus: or deficiency in total calories and protein (skeletal appearance); kwashiorkor: deficiency in protein (swollen belly appearance)
|main page| |background| |03028: Physiology| |03048: Anatomy|
|03050: Invertebrate Zoology| |03051: Vertebrate Zoology| |03074: Economic Botany|
Please send comments and questions to: cronewil@hvcc.edu
Copyright 1999 by Wilson Crone
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This page updated on October 4, 1999