Tissue: A group of cells performs the duty of manufacturing
food; another group stores it, while the other group conducts the transport of food
materials. There is further a group of cells that gives mechanical strenght to
some organs. In many cases it is observed that a group of cells originating
from a single origin remain closely attached in a place and collectively
perform a similar type of function. This type of cells in a group is called
tissue. In multicellular organisms division of labour is the main cause of
formation of tissue.
Type of tissue: Cells of all tissues do not have the power of cell division but some of them have. Therefore tissues are of two types in terms of the power of cell division.
Type of tissue: Cells of all tissues do not have the power of cell division but some of them have. Therefore tissues are of two types in terms of the power of cell division.
1. Meristamatic tissue &
2. Permanent tissue.
1. Meristamatic tissue :
Meristamatic cells compose the Meristamatic tissue. The
cells of this tissue divide repeatedly. These tissues are found in the tress.
Due to their presence plants increase in size very rapidly. Other permanent
tissues are originated from Meristamatic tissue.
Characrteristics of Meristamatic tissues:Characrteristics of Meristamatic tissues are as follows :
1. Cells possess the power of cell division.
2. Usually the cells are rectangular of oval.
3. Cell wall is made of cellulose and is thin.
4. Nucleus is large and the cytoplasm is denser.
5. Usually no vacuole is seen in the cell.
6. Usually there is no intercellular space in Meristamatic tissue, so
the cells are arranged compactly.
2. Permanent tissue:
Cells of permanent tissues are not capable of cell division, for which
they are called Permanent tissue. They
are originated from Meristamatic tissues. All tissues other than the
Meristamatic ones are permanent tissues.
Characteristics of Permanent tissue:
1. Cells of these tissues have no power of division.
2. Cells are well developed and properly shaped.
3. Cell wall is comparatively thick.
4. Nucleus of the cells are bigger and cytoplasm is dense.
5. Usually there are vacuoles in the cell.
6. There may have intercellular spaces in between cells.
