Latex

LATEX, a cellular juice of a special character contained in many plants in special receptacles, which are represented either by individual cells (e.g., in the maple) or, more often, by long tubes (laticifers). The latter, by their origin, are either overgrown individual cells (Euphorbiaceae) or the result of the fusion of many cells located one after another (this type is the most frequent). Upon wounding the plant, latex flows out in the form of mostly white drops, resembling milk (hence the name); less often it is colored yellow or orange, as in the greater celandine (Chelidonium) or the saffron milk cap mushroom (Lactarius deliciosus). By chemical composition, latex is very complex and different in different plants. For the most part, water represents its main constituent by quantity. In it, partly in solution and partly in the form of an emulsion, there is a range of substances: mineral salts, sugars, starch grains, glycosides, fat droplets, protein substances, alkaloids, enzymes, resins, rubber, gutta-percha, and others. In the tropical cow tree (Galactodendron americanum from the Moraceae family), the composition of latex is close to cow's milk and is consumed as food. In the poppy, the most essential part of the latex is alkaloids (opium alkaloids). In Carica papaya, the latex is rich in proteolytic enzymes and finds application in medicine in this sense. The most technically important constituent parts of latex are gutta-percha and rubber. They are distributed in very many plants, but are especially richly represented in some, which are used for obtaining these products. Rubber is extracted mainly from incisions in the bark of tropical trees of Hevea (Euphorbiaceae), Ficus (Moraceae), and others, and gutta-percha mainly from Palaquium (Sapotaceae). Significant quantities of rubber are also contained in some herbaceous plants or subshrubs, such as the Mexican guayule (Parthenium argentatum) or some Scorzonera (both Compositae). These plants can also grow in the USSR (in Central Asia, in the Caucasus), and attempts to use them have begun. The physiological significance of latex for the plant is not entirely clear. The content in it of such substances as carbohydrates, fats, and proteins allows one to see here a receptacle for reserve nutrients. On the other hand, such substances as resins and rubber are excretions not consumed further by the plants. Perhaps they have an indirect significance for sealing wounds, and on the other hand, possessing, along with some other substances, a burning taste or poisonous properties, they can serve as protection against being eaten by animals.