leaves can be very different from each other, but they all have in common.Most of the leaves consist of petiole and leaf blade (called petiolate), but there are sessile leaves without petiole and attaches directly to the stem base plate.Sometimes, near the base of developed stipules.
Leaves are simple or complex (consisting of one or more leaf blades respectively), different in form may have different edge.They observed the characteristic for each type of plant venation types: parallel, arc, net, pinnate, palmate.Veins are composed of conductive beams attached sheet strength is carried out and the solutions of
top and bottom leaf blades are covered with a thin, transparent coating of skin tissue.It has many stomata submitted stomatal guard cells and slit.Through these openings water is evaporated, and gas exchange.
Pulp sheet under the skin consists of a base fabric.Two or three layers of fabric forming a bar, which is especially a lot of chloroplasts, and further space represented spongy tissue with large and frequent intercellular spaces filled with air.
Sheet size, its form and structure related to the living conditions of the plant organism.In wet ground leaves of plants are often large and have a large number of stomata, whereas in dry - small in size and tend to have special tools to reduce evaporation.These appliances include: wax coating, a small amount of stomata, "compact" form of the sheet (spikes), etc.At aloe and agave, called succulents, water is stored in the soft and succulent leaves.
to adapt to environmental conditions the leaves of some plants mutated, gaining specific to a leaf function.So, barberry thorns and cacti not only reduce evaporation and help maintain moisture, but also protect the plant from heavy eating animals.Tendrils of pea support stem in a vertical position.
Leaves predatory carnivorous plants such as sundew, adapted for catching and digesting small insects.The hairs on the leaf blades stands out sticky liquid that attracts insects with its brilliance.Sitting on a leaf, animals bogged down in it, and then the hair and the plate, bend, cover the victim caught.After that, the plant absorbs and digests the insect tissues that can compensate for the lack of nitrogen in the soil (eg, peat bogs, where it grows sundew).
In many semi-arid plants, which include, for example, the feather, the stomata are on the upper side of the sheet, and with a lack of moisture sheet rolled into a tube.The cavity formed inside the tube, isolated from dry ambient air increases the concentration of water vapor, whereby the evaporation decreases.