User:VIJMAU/sandbox/What Is PLANT TISSUE

Tissue, The group of cells which are similar in structure and works together to get a particular function is called tissue and the group of tissue forms a organ. Plant tissue- Plants have a large number of supportive tissue. But Because the plants does not show locomotion. They requires less energy so the supportive tissue they contain is bassically dead. There are two types of plant tissue- 1.) Meristematic tissue 2.) Permanent tissue 1.) Meristematic tissue- The meristematic tissue is generally known as dividing tissue. The cells of this tissue are very active. This cells contain dense cytoplasm they have thin cellulose walls and also have prominent nuclei.They lack vacuoles. Meristematic tissue is of three types – i) Apical meristem- It is present at the growing tips of roots and stem and increases the length of the stem and the root. ii) Cambium- The girth of the stem or root increases due to cambium. iii) Intercalary meristem- It is sees in some plants located near the node. 2.) Permanent tissue- When the meristematic lose the ability to divide it converts into permanent tissue. Permanent tissue is of two types- i) Simple permanent tissue – A few layers of cells beneath the epidermis is bassiclly known as simple permanent tissue.The most common simple permanent tissue is parenchyma. A) The parenchyma contains unspecialised cells with thin cell walls and mostly cells are living cells. This cells are loosely arranged because of this large spaces are found in this tissue. This tissue basically stores food. In some conditions it contains chlorophyll and it hence performs photosynthesis than it is known as chlorenchyma and in aquatic plants large air cavities are present in parenchyma this type of parenchya tissue is known as aerenchyma. b) Collenchyma – The flexibility of plants is due to collenchya. Due to this the plants can bend from various part like tendrils and stems. This tissue also provides mechanical support to the plant. This tissue can be found in leafs stalks below the epidermis. This tissue contains living cells and at the corners this are elongated and are irregularly thickened. This does not have large spaces between them they have very small spaces between them. c) Sclerenchyma - This tissue is responsible for the hardness and stiffness of plant. An ex is the husk of coconut it is made up of sclerenchymatous tissue. This tissue generally contains dead cells and they are long and narrow as the walls are thickened due to lignin. The cells does not have any space. ii) Complex permanenet tissue- The complex tissue is made up of more than one type of cells. All these cells coordinate to perform a common function. The examples of the complex tissue is xylem and phloem.These both tissue are conducting tissues. a) Xylem- It consists of tracheids, vessels, xylem parenchyma and xylem fibres. In this trachieds and vessels have thick walls and many are dead cells when they mature. Trachieds and vessels are tubular structures. This feature allow them to transport water and minerals vertically. The parenchyma stores food. Xylem fibres are mainly suppotive in functions. b) Phloem- This tissue is made up of five types of cells sieve cells, sieve tubes, companion cells phloem fibres, phloem parenchyma. In this sieve tubes are tubular cells with perforated walls. Phloem transports food from leaves to other parts of the plant. Except phloem fibres, other x phloem cells are living cells.