Science, Tech, Math › Science All About the Tobacco Plant Share Flipboard Email Print John Harding Photography/Getty Images Science Biology Botany Basics Cell Biology Genetics Organisms Anatomy Physiology Ecology Chemistry Physics Geology Astronomy Weather & Climate By Shanon Trueman Professor of Biology M.S., Microbiology and Plant Pathology, University of Massachusetts-Amherst B.S., Agronomy, University of Connecticut Shanon Trueman is an adjunct professor of microbiology at Quinnipiac University and a plant research analyst for Nerac and Earthgro. our editorial process Shanon Trueman Updated January 16, 2020 Tobacco was cultivated and smoked for thousands of years in the Americas before European explorers discovered it and brought it back to their homelands. It is now used for more than recreational smoking or chewing. History and Background of Tobacco Nicotiana tabacum is the Latin name for tobacco. It belongs to the plant family Solanaceae, as do potatoes, tomatoes, and eggplant. Tobacco is native to the Americas, and cultivation was thought to have begun as early as 6000 BCE. Leaf blades likely were wilted, dried, and rolled to make primitive cigars. Christopher Columbus noted Cuban natives smoking cigars when he discovered America, and in 1560, Jean Nicot, the French ambassador to Portugal, brought tobacco to England and France. Nicot made a fortune selling the plant to Europeans. Nicot also reportedly gifted tobacco to the queen of France to cure her headaches. (The Latin genus name for tobacco, Nicotiana, was named for Jean Nicot.) Anatomy and Physiology The cultivated tobacco plant normally grows to one or two feet high. The five flower petals are contained within a Corolla and can be colored white, yellow, pink, or red. The tobacco fruit measures at 1.5 mm to 2 mm, and consists of a capsule containing two seeds. The leaves, however, are the most economically important part of the plant. The leaf blades are enormous, often growing to 20 inches long and 10 inches wide. The leaf shape can be ovate (egg-shaped), obcordate (heart-shaped) or elliptic (oval, but with a small point at one end.) The leaves grow toward the base of the plant, and can be lobed or unlobed but are not separated into leaflets. On the stem, the leaves appear alternately, with one leaf per node along the stem. The leaves possess a distinct petiole. The underside of the leaf is fuzzy or hairy. While the leaves are the plant part containing the nicotine, the nicotine is manufactured in the plant roots. Nicotine is transported to the leaves via the xylem. Some species of Nicotiana have very high nicotine content; Nicotiana rustica leaves, for example, can contain up to 18% nicotine. Growing Tobacco Plants Tobacco is cultivated as an annual but is actually a perennial and is propagated by seed. The seeds are sown in beds. One ounce of seed in 100 square yards of soil can produce up to four acres of flue-cured tobacco, or up to three acres of burley tobacco. The plants grow for between six and 10 weeks before the seedlings are transplanted into the fields. The plants are topped (their heads removed) before the seed head develops, except for those plants that are used to produce next year's seed. This is done so all the plant's energy goes to increase the size and the thickness of the leaves. The tobacco suckers (the flowering stalks and branches, which appear in response to the plant being topped) are removed so that only the large leaves are produced on the main stem. Because growers want the leaves to be large and lush, the tobacco plants are fertilized very heavily with nitrogen fertilizer. Cigar-wrapper tobacco, a staple of Connecticut agriculture, is produced under partial shade—resulting in thinner and less damaged leaves. Plants grow in the field for three to five months until harvest. The leaves are removed and purposely wilted in drying barns, and fermentation takes place during curing. Diseases striking tobacco plants include: Bacterial leaf spotBlack root rotBlack shankBroomrapeDowny mildewFusarium wiltTobacco mosaic virusWitchweed Pests that attack the plant include: AphidsBudwormsCutwormsFlea beetlesGrasshoppersGreen June beetle larvaeHornworms Tobacco Types Several types of tobacco are grown, depending on their use: Fire-cured, used for snuff and chewing tobaccoDark air-cured, used for chewing tobaccoAir-cured (Maryland) tobacco, used for cigarettesAir-cured cigar tobaccos, used for cigar wrappers and fillersFlue-cured, used for cigarette, pipe, and chewing tobaccoBurley (air-cured), used for cigarette, pipe, and chewing tobacco Fire-curing is basically what the name suggests; open fires are used so that the smoke can reach the leaves. The smoke makes the leaves darker colored and more distinctly flavored. No heat is used in air curing except to prevent mold. In flue-curing, heat is applied in such a way that no smoke reaches the leaves hung in racks. Other Potential Uses As smoking rates have been vastly reduced over the last 20 years, other uses have been found for tobacco. Tobacco oils can be used in biofuels, including jet fuel. And researchers in India have patented an extract from tobacco called Solansole for use in several drug types that could treat diabetes, Alzheimer’s disease, cystic fibrosis, Ebola, cancer, and HIV/AIDS.