Some plants are composed of a single cell (unicellular), as bacteria, or more cells (multicellular), with no differentiated organs, the body having a tal, as most algae, fungi and lichens.Cells in body of multicellular plant differ in form, structure and function. The cells with the same form and function are grouped into tissues. Association of several types of tissues has the result as component organs of plant body. Each organ (root, stem, etc..) has a role in plant's life, which fulfils it through the activity of component tissues.
The main tissues of plant are:
The protective tissue (defensive).
Skin covering bodies, defending them with the help of external membrane of cells, more thickened, sometimes mineralized or waxed.
Mechanical tissue (supportive) provides strength and soundness of the plant.
Fundamental tissues (parenchyma) have the largest spread in the plant body, performing some capital functions of their lives are: cortical parenchyma,the basic tissue of stem bark and root, parenchyma of the spinal of same organs; assimilator parenchyma, rich in chloroplast, has role in photosynthesis, reserve parenchyma store reserve substances (starch in potato); parenchyma aquifer accumulates water and mucilages, etc.
Conductive tissues ensure saps movement in the body plant.
Origin Tissues (embryonic), the active proliferation of cells forming tissues of plants.