Types of Plant tissues:
(1) Meristematic tissue: Meristematic tissues are group of cells, which have the ability to divide.
This tissue consists of small, cubodial densely packed cells, which keeps on dividing to form new cells.
These tissues are capable of stretching, enlarging and differentiate into other types of tissues as they mature.
Meristematic tissues give rise to permanent tissues.
There are three types of meristem based on the origin of meristematic cells :- Apical meristem, Lateral meristem and Intercalary meristem.
(a) Apical meristem is the region at the tip of the plant body. Thus, apical meristem helps in the increase in the height of the plant.
(b) Lateral meristem is a meristem located parallel to the sides of a stem or root, responsible for the thickening of the stem or root by the addition of secondary growth.
(c) Intercalary meristem is a meristem developing between regions of mature or permanent tissue (as at the base of the grass leaf).
(2) Permanent tissues:The tissues, which are derived from the Meristematic tissues, are called as permanent tissues.
They are the tissues, which have lost their ability to divide as they have attained their mature form.
Permanent tissues may be classified into three main groups:Simple,Complex and Special tissues.
(a) Simple Tissue:
Simple tissues are homogeneous and composed of structurally and functionally similar cells.
These are of three types:
Parenchyma is the most common tissue which is morphologically and physiologically simple and unspecialized. These cells are found in epidermis, cortex, pericycle, pith etc. They are responsible for photosynthesis, storage of food, secretion etc.
Collenchyma are living tissues composed of more or less elongated cells and often have some chloroplast to carry on photosynthesis. It is generally situated below the epidermis.
Cells are long, thick-walled and lignified with tapering ends. These are fibre like in appearance and also known as sclerenchymatous fibre. These are dead cells and perform mechanical function.
(b) Complex tissue:
The complex tissues are composed of different types of cells performing diverse functions.
These are of two types xylem and phloem:
(i) Xylem: Xylem is the one of the two types of transport tissue in vascular plants.The basic function of Xylem is transport water from roots to shoots and leaves,but it also transport some nutrients.
(ii) Phloem: It is the living tissue that transports the soluble organic compounds made during photosynthesis.
(c) Special tissue:
Special tissues are structurally modified and specially organized for secretary function.
These are of two types:
(i) Laticiferous tissue: These are specialized tube like structures known as laticiferous ducts found in many angiosperms.
These ducts are filled with white or yellow latex. Laticiferous ducts are of two types: Latex cells as found in madar and Latex vessels as found in rubber, papaya etc.
(ii) Glandular tissue: It consists of different types of glands which are formed by single cell or group of cells. These secrete resin, oil, mucilage, tannin, gums etc.