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Chemical defense is a strategy employed by many organisms to avoid consumption by producing toxic or repellent metabolites or chemical warnings which incite defensive behavioral changes. [ 1 ] [ 2 ] The production of defensive chemicals occurs in plants, fungi, and bacteria, as well as invertebrate and vertebrate animals.
Plant defense against herbivory or host-plant resistance is a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Many plants produce secondary metabolites, known as allelochemicals, that influence the behavior, growth, or survival of herbivores. These chemical defenses can ...
For example, jasmonic acid can be used to simulate an herbivore attack on plants and thus, induce plant defences. [19] The use of jasmonic acid on tomato ( Lycopersicon esculentum ) resulted in plants with fewer but larger fruits, longer ripening time, delayed fruit-set, fewer seeds per plant and fewer seeds per unit of fruit weight. [ 20 ]
Some chemical defenses once thought to be produced by the plant have since been shown to be synthesized by endophytic fungi. The chemical basis of insect resistance in endophyte-plant defense mutualisms has been most extensively studied in the perennial ryegrass and three major classes of secondary metabolites are found: indole diterpenes, ergot alkaloids and peramine.
Some plants have physical defenses such as thorns, spines and prickles, but by far the most common type of protection is chemical. [ 1 ] Over millennia, through the process of natural selection , plants have evolved the means to produce a vast and complicated array of chemical compounds to deter herbivores.
Exploiting plants’ defence mechanisms against pests or diseases could help to remove our reliance on toxic pesticides. Skip to main content. 24/7 Help. For premium support please call: 800-290 ...
Many plants produce chemical compounds for defence against herbivores. The major classes of pharmacologically active phytochemicals are described below, with examples of medicinal plants that contain them. [1] Human settlements are often surrounded by weeds containing phytochemicals, such as nettle, dandelion and chickweed. [2] [3]
This cost can be seen when plants that use chemical defenses are compared to those plants that do not, in situations when herbivores are excluded. Several species of insects sequester and deploy plant chemicals for their own defense. [34] Caterpillar and adult monarch butterflies store cardiac glycosides from milkweed, making these organisms ...