The following points highlight the top seven functions of plant tissues. The functions are: 1. Meristematic 2. Protective 3. Parenchyma 4. Collenchyma 5. Sclerenchyma 6. Xylem 7. Phloem.
Plant Tissue: Function # 1. Meristematic:
These are small, thin-walled cells, devoid of any central vacuole and situated at the growing points of stems and root. Their chief function is mitosis.
Plant Tissue: Function # 2. Protective:
The cells of these tissues are found on the surface of roots, stems and leaves. Top and bottom surface of these flat cells are parallel and their sides are irregularly arranged.
Plant Tissue: Function # 3. Parenchyma:
These are large, thin-walled, living cells, each having a nucleus and central vacuole. Intercellular spaces are present in between these cells. Parenchymatous cells, present in the areas not exposed to light, possess leucoplast. Parenchyma cells, specialized for the process of photosynthesis, are called chlorenchyma.
Plant Tissue: Function # 4. Collenchyma:
These cells have thick secondary wall, especially at their corners. Mechanical support is provided for the plants by these cells.
Plant Tissue: Function # 5. Sclerenchyma:
In these cells, very thick secondary walls are present in the form of a thick uniform layer around the entire margin. Generally, after the formation of secondary cell wall, the protoplasts of these cells die.
Plant Tissue: Function # 6. Xylem:
It consists of several types of cells like xylem vessels, xylem tracheids. Vessels are absent in the xylem of Gymnosperms. Vessels have thick secondary cells walls which are not deposited in a uniform layer but usually thickened in the form of spiral bands. Spiral bands are not present in the tracheids. Tracheids are tapered at the ends and interconnected by means of pits. Xylem develops into wood.
Plant Tissue: Function # 7. Phloem:
Important cells of this mixed tissue are sieve tubes and companion cells. Sieve tubes have a perforated end walls. Nucleus is absent in the sieve tubes at maturity but present in the companion cells. Chief function of the phloem is the transport of food throughout the plant.