- Tissues are sets of cells which are build of atoms and elements at the most basic level.
- Plants are build of mainly three parts- roots, stems and leaves and these parts of plants are made of tissues to work together.
- Scientists classify plant tissues on the basis of structure and function.
Plant Tissues are of two types- 1. Merismatic Tissue, 2. Permanent Tissue
The Permanent Tissues are of two types-
o Simple Tissue
o Complex Tissue
The Apical Tissues which are Merismatic Tissues are of three types
The complex tissues which are permanent plant tissue are of two types
o Xylem and
Meristematic Tissues- These are tissues in which cell division occurs continuously to produce new cells; such tissues are called Merismatic Tissues or Meristerms.
The main characteristics of Merismatic tissues are listed below.
• It is round, oval or multi faced.
• It has thin wall and cytoplasm is homogeneous.
• The cells in a Merismatic tissue contain single nucleus and dense cytoplasm.
• There found no inter-cellular spaces between the cells.
Apical Merismatic tissues- These tissues are found at or near the tips of roots and shoots. These are responsible for growth of a tree like its height.
Lateral Merismatic Tissues- The growth in the girth of stems and roots of plants occurs due to division of these tissues.
Intercalary Merismatic Tissues- These tissues are found at the base of internode. These are found in grasses and related plants that do not have a vascular cambium or a cork cambium, as they do not increase in girth. The Intercalary Merismatic Tissues are responsible for the regrowth of cut grass.
Permanent Tissues- The permanent tissues are made of mature tissues which have lost ability to division and found definite forms suitable for various tasks. The cells of such tissues may be alive or dead.
Simple Tissue- When a permanent tissue is build up of simple cells, it’s called simple tissue.
Complex Tissue- When a permanent tissue is made up of one or more types of cells, it’s called complex tissue.
Xylem- Generally it is called wood. It is conducting tissue. The two main functions of these tissues are –
1. transportation of water and minerals and
2. providing mechanical consistency.
The age of a plant is determined by counting annual rings of the xylem tissue. This method is called Dendrochronology.
Phloem- The Phloem is conducting tissue. The main function of Phloem tissues is to supply foods prepared by the leaved to different parts of plants.