Land plants are strongly fixed in soil by the root systems and consequently are considered usually as absolutely fixed in space. This representation is not absolutely exact, as all plants are capable to slow movements (tropizmam), necessary to adapt orientation of the bodies to such external factors, as light and gravitation. Besides, some plants make a little faster periodic sleepy movements - put the leaves or petals tsvetkov (see gl. 12). Only few unusual plants possess more appreciable ' impellent ability ' (' power of movement - expression of Charlza of Darwin) and react fast movements to various external factors, including on light, chemical substances, a touch, damage or mechanical vibration. These unusual forms of behaviour concern folding of leaves at Mimosa pudica (' a sensitive plant '), movements at various insectivorous plants and a twisting of short moustaches at many lianas. Functions of these movements as are various, as well as causing them razdrazhiteli. Fast movements at a mimosa can serve for protection against insects and other animals. Movements of insectivorous plants help them to catch insects who serve as additional food for these basically avtotrofnyh organisms. The twisting of short moustaches of a liana round firm objects provides to it a mechanical support and thus allows a plant to reach considerable height without the big supporting trunk. Short moustaches sometimes suppress also growth of the next competing kinds, thereby raising ability of a plant to survive in the conditions of big ' narrownesses '.

Fast movements of plants drew attention more two millenia ago and till now continue to cause interest in researchers. Studying of the movements peculiar to plants, has helped to open many new aspects of their physiology. For example, research of phototropic curvatures has led to the first assumptions of existence rostovyh hormones. Niktinastichesky movements of leaves have suggested for the first time that organisms possess an inner clock, and modern works help us to understand interactions between these hours and light at the biological processes connected with time. experiences with tigmonasticheskimi plants (sensitive to a touch) have shown that the electric signals extending in a plant, serve, as well as at animals, the important way of communication between various cages of an organism. In the present chapter we will consider some details of these aspects of physiology of green plants.

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