Like all live beings, plants live in potentially hostile world. From the moment of germination of a seed they begin the struggle against other plants for a place in space, for light, water and mineral substances. Bacteria, parasitic mushrooms, insects, nematody both other patogeny and wreckers attack young, weak shoots. when plants will grow up, animals join these enemies also every possible rastitelnojadnye. To have possibility to survive and finish the life cycle, plants in the course of evolution should arm with various protective mechanisms which allow them to avoid patogenov and wreckers or to frighten off them. Wild-growing forms, undoubtedly, have succeeded in it, however at our cultural plants deduced for satisfaction of requirements of the person, such protective mechanisms quite often are absent, and the person should incur their protection. With that end in view it uses the different ways helping plants to survive and reach a maturity: application of various chemical preparations plays this business a leading role.
Plants have the various structural and physiological mechanisms allowing them to resist especially adverse influences, for example to very high and very low temperatures or a long drought. for protection against potential wreckers and illnesses every possible adaptations - structural, physical or chemical are required to a motionless green plant many. Thorns and burning hairs reliably protect plants from large animals, however they are available not for all kinds of plants, and, obviously, they are useless against such small wreckers, as insects. As the most important weapon against various enemies the chemical system of the protection numbering thousand of various connections serves almost at all plants. the few are necessary for vital processes of a plant from them only very much, and the others make that arsenal which plants have for reflexion of attacks potential patogenov and wreckers. Let's consider some protective mechanisms of plants in more details.
Adverse temperature conditions and a water lack
Insects and plants
Mushrooms, illnesses a plant and stability to illnesses
Competing interactions with other members of vegetative community