The bud of a plant is a rudiment of escape. Among themselves kidneys differ in structure, to functions, a location on a stalk and time of germination. They play very important role in plant life.
The vegetative kidney is the shortened escape which consists of a rudimentary stalk and rudimentary leaves. This kidney still is called growth as the new leaf grows from it. Such kidneys of the small size, have the extended and pointed form. After germination from vegetative kidneys escapes of various length appear.
Generative kidneys have well developed rudiments of flowers, from them only flowers and fruits develop. Such kidneys have generally stone fruits. If the kidney has one flower, then it is called a bud.
There are kidneys which have rudiments of flowers, leaves, inflorescences and stalks at once. Such kidneys are called mixed or vegetative and generative. These kidneys most often meet in seeded breeds of plants. The mixed kidneys in comparison with vegetative large and roundish.
Kidneys have brown, gray and brown coloring, outside they are covered with scales which protect a kidney from cold and damages. Scales which emit resinous substances, for example, at a birch and a poplar are called closed or protected. There are kidneys which have no scales, they are called unprotected or naked. But naked kidneys are protected from cold by a dense down. At plants which need to transfer sharp temperature drops, for example, at a lily of the valley the kidneys are on underground escapes or in the lower part above the ground. At a cactus the kidney scales were transformed to needles which perform protective function. If the kidney is on the end of escape, then it is called top or terminal. Such kidney performs function of growth of escape in length. If the kidney is located sideways a stalk, then it is called side or pazushny. Kidneys can be one by one or groups in bosoms of leaves. Thanks to it the kidney not only is protected by a leaf from above from mechanical damages, but also from a leaf the kidney receives a large amount of nutrients. Kidneys which vnepazushny are called subordinate clauses. In the arrangement they have no regularity. Their main function is vegetative reproduction. Escapes grow from additional kidneys. There are "renewal kidneys". These are buds of perennial plants which because of adverse conditions are in rest, at approach of suitable weather they form escapes. Also there are sleeping kidneys. They remain unsolved long time. Such kidneys happen at perennial plants, deciduous trees and bushes. The sleeping kidneys can not develop several years. Cutting or death of a trunk of a plant can serve as a factor of their development. The sleeping kidneys are of great importance for bushes. If the main trunk stops the growth, then the sleeping kidneys which form affiliated trunks begin to develop. Their sizes can exceed a maternal trunk. The regularity is peculiar to plants: are formed of maternal kidneys affiliated, and later and affiliated kidneys turn into maternal.