Habitat Loss

By far the most significant threat to plant species is habitat loss or destruction. Habitat loss can occur because of resource harvesting for food, medicine, and other products, deforestation, and the conversion of wilderness for agricultural, industrial, or urban uses. Wood consumption and tree clearing for agriculture and development threaten the world's forests, especially the tropical forests, which may disappear by the mid-twenty-first century if sufficient preventive action is not taken....

Nitrogen Fertilizer from Legumes

The importance of legumes as a green fertilizer has been recognized for centuries. As early as the third century b.c.e., the Greek philosopher and scientist Theophrastus recommended that beans should be planted to enrich farm soils. Then, as now, a common agricultural practice was to rotate cereal crops, such as corn or wheat, with legumi nous crops, such as clover or alfalfa (Medicago sativa). The legumes used as green fertilizer not only contribute nitrogen to the soil but also can be...

Fighting Asthma Gastrointestinal Disorders Parasites

The major anti-asthma drugs come from ephed-rine, extracted from the ma huang plant (Ephedra sinaica), and its structural derivatives. Plant-derived drugs that affect the gastrointestinal tract include castor oil, senna, and aloes as laxatives, opiate alkaloids as antidiarrheals, and ipecac from Cephaelis acuminata as an emetic. The most useful plant-derived antiparasitic agent is quinine, derived from the bark of the chincona plant (Chincona succirubra). Quinine has been used to control...

Isoflavonoids as Phytoestrogens

Isoflavonoids are a type of secondary metabolite and are found almost exclusively in the legume pea family of plants. They are known to function in plant defense. They have been shown to deter herbivores and also to facilitate a plant's defense response to pathogen attack. Interestingly, some isoflavonoids have chemical structures that, in overall size, shape, and polarity, resemble estrogens. The resemblance includes the flatness, or planarity, of the molecules and the positions and...

Simple and Compound Leaves

Simple Leaf And Compound Leaf

To discriminate between simple and compound leaves, one may locate the axillary bud at the base of a leaf petiole in the node region of the stem. This area signifies the basal end of the entire leaf in both simple and compound leaves. A simple leaf has only one blade, or lamina, associated with it. There are no leaflets. In singly compound leaves, the leaf is sudivided into leaflets, which attach to a central rachis axis . The rachis is continuous with the petiole, which attaches to the node...

List Of Illustrations Charts And Tables

Acid Precipitation pH Scale bar Africa, Desertification of African Countries with More than 15 Percent Arable Land, Leading Agricultural Crops of table . . . I-15 African Rain Forests Africa's Agricultural Products Air Pollutant Emissions by Pollutant and Source, 1998 table I-45 Algae, Classification of Algae, Types of Angiosperm, Life Cycle of an Angiosperms and Continental Drift Antibiotic Resistance, The Growth of Ants and Acacias Asian Countries with More than 15 Percent Arable Land,...

Alphabetical List Of Contents

Acid precipitation 1 Active transport 4 Adaptive radiation 10 African agriculture 12 Agricultural crops experimental 20 Agricultural revolution 23 Agriculture history and overview 24 Agriculture marine 29 Agriculture modern problems 31 Agriculture traditional 34 Agriculture world food supplies 37 Alternative grains 52 Anaerobes and heterotrophs 54 Anaerobic photosynthesis 56 Angiosperm cells and tissues 58 Angiosperm evolution 61 Angiosperm life cycle 65 Angiosperm plant formation 69...

Garden Plants Shrubs

Categories Angiosperms economic botany and plant uses gardening Shrubs are perennial, woody plants that have multiple ecological uses and are economically important for a variety of landscape purposes. Like trees, the shrubs consist of both primary and secondary cambium cells that ultimately form wood or bark , but unlike trees, shrubs typically have multiple stems and are somewhat shorter in height. Native and nonnative shrubs have many uses, both in private gardens and as elements in...