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Leaf of a plant - an extremely important part of the plant . List - part of the shoot . The main features of it are photosynthesis and transpiration . Sheet is characterized by a high morphological plasticity, large variety of shapes and adaptive capabilities. The base plate can be extended in the form of oblique leaf-shaped formations - stipules on each side of the sheet. In some cases, they are so great that they play a role in photosynthesis . Stipules am free or adnate to the petiole , they can be shifted to the inside of the sheet and then they are called axillary . Base of the leaves can be turned into the vagina surrounding the stem and prevent it from bending .
External structure of the sheet Leaf blades vary in size from a few millimeters up to 10-15 meters and even 20 ( in trees ) . Life expectancy leaves no more than a few months , some - from 1.5 to 15 years. The size and shape of leaves are hereditary traits. part of the leaf Leaves - lateral vegetative organ growing from the stem , which has bilateral symmetry and the growth zone at the base . Sheet generally consists of the leaf blade , petiole (except leaves sessile ), for a number of families characterized stipules . Leaves usually simple, with one lamina and complex - with a few leaf blades ( leaves ) . Leaf blade - extended generally flat portion of the sheet that performs the function of photosynthesis , gas exchange , transpiration , and in some species - vegetative propagation . The base sheet (sheet cushion) - part of the sheet , connecting it to the stem . Here is an educational fabric, giving rise leaf blade and petiole . Stipules - Double leaf formation at the bottom of the sheet. They may fall off when deploying sheet or stored . Protect the axillary lateral buds and educational fabric gusset plate . Petiole - a neck plate , connecting its base leaf blade to the stem . It has a crucial function : directs sheet to the light , is the location of the educational fabric gusset , which is growing at the expense sheet. In addition, it has a mechanical to reducing impacts on the leaf blade from rain, hail, wind , etc. Источник материала Свободная публикация материалов сайта при условии наличия ссылки на сайт. Здесь общение с автором проекта по вопросам рекламы, развития и поддержки проекта, обмена информацией, авторских прав - в контакты. Почта администратора сайта - evgeniy@fedoroff.net. Статья 29.4 Каждый имеет право свободно искать, получать, передавать, производить и распространять информацию любым законным способом. Перечень сведений, составляющих государственную тайну, определяется федеральным законом. © fedoroff.net | |
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