Tropical and subtropical plants

Table I. Protein and Free Amino Acid Compositions of Leaves from Tropical and Subtropical Plants [Adapted from Hall et al. (7 )]...

Rotenone is the toxic principle of several tropical and subtropical plants, the chief of which is derris. It is a complex organic heterocyclic compound and rotenone derivatives are stomach and contact poisons. 

In common with many other tropical and subtropical plant extracts used locally for their alleged antimalarial properties, the reputation of... 

Since 2500 BC, farmers have used pesticides to prevent damage to their crops. The first known pesticide was elemental sulfur, used to dust crops in Sumeria about 4500 years ago. By the fifteenth century, pesticides containing arsenic, mercury, and lead were being applied to crops. In the seventeenth century, nicotine was extracted from tobacco leaves as nicotine sulfate for use as an insecticide. In the nineteenth century, two more natural pesticides were introduced pyrethrum (extracted from chrysanthemums) and rotenone (extracted from the roots and stems of several tropical and subtropical plant species of the genus Lonchocarpus or Derris) [Miller (21A46)]. 

There are other more descriptive methods that are sometimes used to differentiate between tropical and subtropical plants. Plants that will not grow at temperatures below 5°C can be considered strictly tropical. In addition, those plants that are found in the temperature zone where coconut palms flourish are considered tropical while those found in the temperature zone where oranges thrive are considered subtropical (Popenoe, 1974). 

In the course of an asymmetric synthesis of (+)-erysotra-midine, which can be found in tropical and subtropical plants of the erythrina genus and show a wide range of pharmacological effects, Simpkins and co-workers found that treatment of aldehyde 149 with TBTH efficiently led to the radical addition (91%), via an 0-stannyl ketyl radical. Although the hydroxylactam was formed as a mixture of diastereomers at the new carbinol center (ca. 3 1 ratio), subsequent dehydration with Burgess reagent rendered alkene 150 as the sole product in 80% yield (Scheme 25.70). 

Cotton is the common name for Gossypium spp., a tropical and subtropical plant from the Malvaceae family. In 2014/15, 44.34 MMT of cotton oilseeds were produced worldwide, generating 15.48 and 5.13 MMT of cottonseed meal (mainly for ruminant feeding) and oil, respectively, located mainly in China, India, United States, and Australia (Agriculture, 2015). 

Whereas commercial production of castor oil existed ia the United States ia the 1800s, production shifted to tropical and subtropical countries ia the early 1900s. World War I, World War II, and the Korean conflict each iafluenced efforts to produce hybrid castor species and iacrease U.S. planting, and by the late 1960s, approximately 80,000 acres of castor were grown ia the United States produciag 29,500 metric tons of castor oil. U.S. production was competitive until 1972 when Federal price supports were withdrawn. U.S. production dropped almost to zero by 1974. 

Ocean thermal energy conversion (OTEC) power plants generate electricity by exploiting the difference in temperature between warm water at the ocean surface and colder waters found at ocean depths. To effectively capture this solar energy, a temperature difference of 35°F or more between surface waters and water at depths of up to 3,000 feet is required. This situation can be found in most of the tropical and subtropical oceans around the world that are in latitudes between 20 degrees north and 20 degrees south. 

The family Rubiaceae consists of about 450 genera and 6500 species of tropical and subtropical trees, shrubs, climbers, and herbs that are known to abound with iri-doid glycosides (monoterpenoid alkaloids, tannins, and anthraquinones). When looking for Rubiaceae in field collection, one is advised to look for plants with opposite simple leaves with an interpetiolar stipule, tubular flowers, which are often white, and capsules, berries, or drupes. 

Cow pea and urd bean, two common legumes are only slightly lower. An excellent review by H. D. Tindall of the leguminosae plants indicates most of their seeds have high protein contents, are directly consumable, and they are easily grown in tropical and subtropical climates (30). 

A downside of the rise of mammals, specifically including humans, is that the sixth major extinction of life on Earth is happening now. As noted above, we are losing 4-6 species an hour, 27,000 0,000 species a year, mostly in the tropical and subtropical forests. The tremendous loss of species is the result of habitat destruction, overhunting, introduction of exotic species of animals and plants into new habitats, and the diseases carried by these exotics. One of the most valuable resources on Earth— biodiversity—is being sacrificed, fhe result of a burgeoning human population and its activities. 

Rehm, S. and Espig, G. 1991. The Cultivated Plants of the Tropics and Subtropics. Cultivation, Economic Value, Utilization. Berlin Verlag Josef Margraaf Scientific Books. 

Critics of waste incineration argue that these plants often create more environmental problems than they solve. They point out, for example, that incinerators are a major source of dioxin, mercury, and halogenated hydrocarbon release into the atmosphere. In addition, incinerators are very expensive to build and to maintain, and they provide fewer jobs to members of the surrounding community than other methods of solid waste disposal. Also, companies have a dismal record of siting incinerators in disadvantaged communities, where residents suffer the worst consequences of incinerator use. Finally, waste-to-energy incinerators are of little value in tropical and subtropical countries, where the cost of plants and the availability of additional energy sources make them impractical. 

However, the chief source of chloroform is probably chlorination of naturally formed humic acids, especially in the tropics and subtropics. The World Health Organization has set a limit of 30 fig L-1 as the acceptable chloroform concentration in drinking water. Overzealous use of chlorine to sterilize sewage-plant effluent has also led to major fish kills in rivers. 

Plants of the genus Dioscorea are the most common source of diosgenin. This genus occurs abundantly in tropical and subtropical regions throughout the world. 

Tropical and subtropical epiphytes or rock plants. Psibtum nudum. 

Despite substantial advances in synthetic organic chemistry, many secondary metabolic compounds are either too difficult or too costly to synthesize. Some complex mixtures like rose oil cannot be constituted by manufacture. The majority of the plants that produce commercially useful substances are grown in tropical and subtropical regions of the world. As a result, the availability and costs of these materials depend on the political and economic circumstances of the countries of origin. 

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