Introduction

Tissues are the set of similar types of cells that originate from the same origin and are designed to perform the same and integrated function for the plants. These kinds of simple tissues are composed of a singular and the same kind of cell. Simple tissues are almost the same in length, depth, and breadth. These types of cells are polygonal or oval in structure.  The walls of the simple tissues are usually thick and contain a sufficient amount of protoplasm.

What is simple tissue?

“What is simple tissue,” can be defined as the composition of singular cells that look the same structurally and functionally. It generally has a thick layer of walls and is full of protoplasm. It is one of the most abundant and common tissues that can be found easily in the plant body. 

What are the different types of simple tissue? 

A simple tissue can be classified into three different types such as parenchyma, collenchymas, and sclerenchyma.  These three different types are elaborated on below.

Parenchyma

This kind of cell has a thin layer of cell walls and is living. Parenchyma cells are round or oval in structure. Inside a parenchyma cell, dense cytoplasm and a large size vacuole are present in the centre of the cell. Parenchyma cells are found in the soft parts of a plant such as the pith and cortex. Parenchyma tissues mainly function as packing tissue that provides mechanical support to a plant. Parenchyma cells are made up of undifferentiated, living, and simple cells that are designed in a fashion that can perform various operations.  

Structure of parenchyma cells

• It contains a protoplast and nucleus.
• The parenchyma cells are polyhedral or are diametric in structure. Sometimes they may be found in oval, polygonal or elongated shapes. 
• These cells of parenchyma are packed closely or may contain small intercellular gaps. 
• It is made up of a thin layer of the cell wall that is built of hemicelluloses and cellulose. 
• Parenchyma cells have numerous small size vacuoles. Sometimes in old parenchyma cells, small size vacuoles unite together to form a large size vacuole that is located in the centre of the cell. 
• Cell vacuoles contain an uncountable amount of water and it acts as a reservoir of water. 
• Hydraulic features of parenchyma cells give this parenchyma cell mechanical support.
• Sometimes, few cells of parenchyma that are bound to perform secretory functions, contain protoplasm that is full of ribosomes, ER (endoplasmic reticulum), and Golgi bodies. 

Functions

Parenchyma cells perform different functions. They are discussed below.

• Storage: Since these types of cells have large space or gaps between cells that can perform the function of storage. It can be used to store fats, water, droplets of oil, and other different substances. 

• Photosynthesis: Parenchyma cells function in the process of photosynthesis of a plant that is necessary. 

Collenchymas

Collenchymas is a type of simple tissue that helps in the formation of plant tissue. It helps the plants by giving rigidity and elasticity. It is made up of thick and strong strands of cellulose that are twisted with each other. Cells of collenchymas generally grow constantly that is why it is easily found on the stems and roots of the plants. 

Structure

• It is made up of living cells and the cell wall is generally thick
• Collenchymas cells provide stringency to the growing plants. It provides mechanical support to the leaves, stems.
• Helps in the prevention of breaking and meandering of stems.
• Some cells contain chloroplast that helps in the process of photosynthesis. 
• Cells of collenchymas that lie in leaves that restrain it from tearing. 
• Provides elasticity to organs of plants to become stretchy and make them smooth. 

Functions

• This type of cell helps in providing mechanical support to the plants.
• It allows the plants to bend without any teasing or breaking.
• Provides flexibility to stem, leaf, petiole of the growing plants.

Sclerenchyma

It is a simple tissue that is composed of dead cells with thick walls that contain lignin. It is generally found in the mature parts of a plant. 

Structure 

• It contains narrow and elongated cells.
• Cells are generally dead without any protoplast in them. 
• The cell wall is thin and has lignin on it. 
• They have both types of cells such as primary and secondary. 

Functions

• It provides rigidity to plants.
• It helps in the formation of hypodermis in xerophytes plants to obstruct water loss.
• It has a role in the plants’ conductive role.
• It also provides mechanical support.

Differences between simple and complex tissue

Simple tissues are homogeneous while complex tissues are heterogeneous. The main function of the simple tissue is to provide repair to the plants and act as storage of food. On the other hand, the complex tissues are connected with the transportation of nutrients, water to the different parts of the plants.

Examples of simple tissue

Examples of simple tissue are parenchyma, sclerenchyma, and collenchymas. These types of simple tissue help in the functioning of the plants. It plays different roles such as healing of wounds, photosynthesis, mechanical support, and storage of food. 

Conclusion

This Simple tissue chapter is an important topic in Biology. For the proper understanding of this topic, one must go through all the basic concepts about simple tissue. In this study, the overview of simple tissue is discussed with help of their definition, types of tissue, the structure of tissue, examples of simple tissue, and their functions. For the proper development of a growing plant, the roles of this simple tissue are discussed thoroughly. Different types of simple tissue and their functions are elaborated.