The cells derived from root apical and shoot-apical meristems and cambium differentiate and mature to perform specific functions. This act leading to maturation is termed as differentiation. During differentiation, cells undergo few to major structural changes both in their cell walls and protoplasm. The living differentiated cells, that by now have lost the capacity to divide can regain the capacity of division under certain conditions. This phenomenon is termed as dedifferentiation. For example, formation of meristems – interfascicular cambium and cork cambium from fully differentiated parenchyma cells. While doing so, such meristems / tissues are able to divide and produce cells that once again lose the capacity to divide but mature to perform specific functions, i.e., get redifferentiated. 

1. Primary Permanent Tissues
Dr. Naveen Gaurav
Associate Professor and Head
Department of Biotechnology
Shri Guru Ram Rai University
Dehradun

2. Permanent Tissues: The cells derived from root apical and shoot-apical meristems and
cambium differentiate and mature to perform specific functions. This act leading to
maturation is termed as differentiation. During differentiation, cells undergo few to major
structural changes both in their cell walls and protoplasm. The living differentiated cells,
that by now have lost the capacity to divide can regain the capacity of division under certain
conditions. This phenomenon is termed as dedifferentiation. For example, formation of
meristems – interfascicular cambium and cork cambium from fully differentiated
parenchyma cells. While doing so, such meristems / tissues are able to divide and produce
cells that once again lose the capacity to divide but mature to perform specific functions,
i.e., get redifferentiated.
Permanent Tissue in Plants
In simple words, the permanent tissues in a plant are those tissues that contain
nondividing cells. The cells are also modified to perform specific functions in the plants. The
cells of the permanent tissue are derived from the meristematic tissue.
The permanent tissue cells are also fully differentiated. The cells are large and a definite
shape and size. You can see intercellular spaces being present in between the cells. Large
vacuoles are also present inside these cells. The metabolism that occurs in the cells of the
permanent tissue is fairly at a lower rate.
The permanent tissue in plants mainly helps in providing support, protection as well as
in photosynthesis and conduction of water, minerals, and nutrients. Permanent tissue cells
may be living or dead.

4. Types of Permanent Tissues
Permanent tissues can be classified into two types. They are:
1. Simple permanent tissue 2. Complex Permanent tissue
Simple Permanent Tissues
These tissues are simple. They are made up of only one type of cell. Here, all the cells that
make up the tissue are similar and have the same structure, with the same type parts. Simple
permanent tissues are again classified into three main types. They are parenchyma,
collenchyma, and sclerenchyma.
Parenchyma – The cells of this tissue are living, with thin cell walls. Cells can be oval or round
in shape. They have a large central vacuole and a dense cytoplasm. The parenchyma tissue is
located in the soft parts of the plant such as cortex and pith. It mainly acts as a packing
tissue, providing mechanical support. It also helps in the storage of food. Based on the
specific functions, parenchyma can be further classified into Aerenchyma and Chlorenchyma.
Collenchyma – These cells are living cells and have an elongated shape. The corners of the
cell wall are thickened. There is very little intercellular space present. The collenchyma tissue
can be located in the leaf stalks, below the epidermis etc. Its main function is to provide
flexibility to the plants as well as mechanical support.
Sclerenchyma – The cells of the sclerenchyma tissue are dead. The cell wall is very thick due
to the deposition of lignin. The cells of this tissue can be in different shapes and sizes. They
are generally located in the leaf veins, hard coverings of the seeds and can also be found
surrounding the vascular bundle. The main function of the sclerenchymatic tissue is to
provide rigidity and mechanical support to the plant body. They also make the plant stiff and
hard.

5. Complex Permanent Tissue
The complex permanent tissues are made up of more than one type of cell. They
coordinate together to perform the same specialized functions in the plant body. They are
classified into two types – Xylem and Phloem
Xylem – The xylem tissue is responsible for the conduction of water and minerals from the
roots to the leaves and stem. It also provides support to the plants. It has four elements.
They are tracheids, vessels, xylem parenchyma and xylem fibres.
Phloem – This complex permanent tissue helps in the translocation of food that is prepared
by photosynthesis in the leaves to various parts of the plant. Phloem consists of four
elements. They are sieve tubes, companion cells, phloem fibres and phloem parenchyma.
Examples of simple and complex permanent tissue:
Husk of a coconut – Sclerenchyma
Cortex of the root – Parenchyma
Veins of the leaves- Sclerenchyma
Vascular bundle – Xylem and Phloem
Note: Meristematic tissues are the tissues which are capable to divide. They are active cells
which are undifferentiated cells. They have abundant cytoplasm and a clear nucleus. They
add cells and contributes in the growth. For example, apical meristematic tissue.
Permanent tissues are the tissues which are specialized and have lost the capacity to
divide. They are differentiated cells which has specific function. They have less cytoplasm
as compared to meristematic tissues. For example, parenchyma cells.

7. Basis Simple Tissue Complex Tissue
Type Homogeneous Heterogeneous
Made of A single type of cell More than one type of cells
Performance Many functions
Majorly take part in
conduction
Distribution Wide Restricted
Occur All parts of a plant
The vascular region of a
plant
Function Food storage To protect
Provides
Transportation of water
and food in plants
Support to plants
Examples Collenchyma, parenchyma Phloem, Xylem

11. Thank you
References: Online notes, notes from research papers and Books by google search Engine