Difference Between Simple and Complex Tissues

Plant tissue is made up of a group of cells that work together to fulfil a specific task for the plant. Each plant tissue has a specific function and can be united with other tissues to form organs like leaves, flowers, stalks, and roots. Between cells and an entire organ, tissue is at a biological organizing level. A tissue is a collection of cells and extracellular matrix from the same origin that work together to perform a defined function. Organs are formed when multiple tissues are functionally grouped together. A brief description of plant tissues and their roles inside the plant is provided here. Meristematic tissue and Permanent tissue are two types of plant tissues that differ in their ability to divide.

Meristematic Tissue

Meristematic plant tissue differs from all other types of plant tissue in that it is the plant's primary growth tissue. Meristems are the source of all cells. The plant tissue that drives above-ground development and determines the plant's direction is known as the apical meristem. In pursuit of water and nutrients, root meristems delve into the soil. The plant is divided into subapical meristems, which carry leaves in various directions. Intercalary meristems provide growth from the plant's centre, allowing the leaves to reach higher into the sunlight.

Meristematic plant tissue is undifferentiated and ready to split into any form of plant cell at the central point. Meristematic cells divide in a non-symmetrical manner. This means that one plant cell remains undifferentiated while the other develops a more specialised form. This cell will then divide and develop into plant tissue, which can assist in the formation of a new organ, such as a leaf. Animal stem cells are analogous to meristematic plant tissue in this way. These cells are totipotent or pluripotent, which means they have the ability to divide into a variety of plant tissue types.

Permanent Tissues

Permanent tissues have lost their ability to divide and are descended from meristematic tissues. They've reached the point where they've reached their full potential. Simple and complex permanent tissues are the two categories.

Simple Tissues 

Simple tissues are the ones that are composed of cells that are structurally and functionally similar i.e. they are formed of only one type of cell. Plant tissue is made up of various different types of cells that are basically the same. The epidermis is the first layer to appear on the skin. Plants and mammals both have epidermis, which performs the same purpose. It's a type of plant tissue made up of thin, densely packed cells that serve to keep the inside of organisms isolated from the outside world. To keep the plant from burning or drying out in the sun, the epidermis is frequently covered in a layer of waxy protection. Guard cells are found in the epidermis and control the stoma, a tiny opening. This stoma regulates air and water flow through the leaves, letting plants transport water and nutrients from the soil.

The epidermis is occasionally covered by cork, a type of basic plant tissue. Cork is a plant tissue that dies and creates an outer coat of bark in woody plants. This tissue is also coated in a waxy material that repels insects, the light, and the elements.

What are the types of Simple Tissues?

There are three types of Simple tissues as mentioned below -

1. Parenchyma

2. Collenchyma 

3. Sclerenchyma

Parenchyma

They are living cells and walled, soft in nature due to the presence of thin-walled cells. Let's start by defining the term "parenchyma." Parenchyma tissues make up the majority of functioning tissues in plants and animals. The word parenchyma is derived from the Greek parénkhyma, or "parenkhein," which means "beside," "to pour in," and énkhuma, which means "stuff of a vessel." A parenchyma is a form of tissue made up of cells that serve a vital purpose.

The simple permanent ground tissues that compose the bulk of plant tissues, such as the soft component of leaves, fruit pulp, and other plant organs, are known as parenchyma in botany (plant biology). What is parenchyma's primary role in plants? Plants' parenchyma tissue is mostly employed for storage and photosynthesis. 

At maturity, parenchyma cells are living tissues capable of cell division. As a result, tissue regeneration and repair will be aided.

The reproductive cells (spores and gametes) have a parenchymatous fundamental makeup. Each zygote's parenchymatous cell is totipotent, meaning it can develop into a fully functional plant.mPlasmodesmata connects plant parenchyma tissues. Many tiny vacuoles exist in plant parenchymal cells, which may join to form a giant central vacuole as they mature. Osmoregulation relies heavily on vacuoles (water concentration regulation). Anthocyanin or tannins may be stored as well. The xyloglucan walls of parenchymal cells that collect or act as storage houses are thick. During germination, the sugar held in these cells serves as an energy source, causing the walls to thin.

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Collenchyma

These are characterized by uneven thick-walled living cells. This uneven thickness of the cell walls divides partially hard giving mechanical support derived essentially from the elongated cells of the ground meristems, procambium sometimes. The cells of the collenchyma are usually lengthy. They are most commonly found in young shoots and leaves. Celery stem strands are a good example of collenchyma tissue. In contrast to sclerenchyma cells, which lose their protoplast as they mature, collenchyma cells are often alive.

The cell wall thickenings of many collenchyma cells are irregular. Angular collenchyma is a condition in which the main cell wall thickens at intercellular contact points. An annular collenchyma consists of collenchyma cells with evenly thickened cell walls.

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Sclerenchyma

These cells have thickened lignified walls which provide them strength by making them waterproof. Between the primary cell wall and the plasma membrane, the sclerenchyma cell constructs a thick secondary cell wall. Lignin is a binder for cellulose fibres that are normally secreted. As a result, the cell wall is strong and can provide structural support to the plant. When the cells reach maturity, they often shed their protoplast and die.

Sclerenchyma can be seen in both ground and vascular tissues in angiosperms. Xylem sclerenchyma (which contains fibre tracheids and libriform fibres) and phloem sclerenchyma are the two forms of vascular sclerenchyma (includes phloem fibres and sclereids). The vascular tissues are supported by both the xylem and phloem sclerenchyma. Bast fibres (secondary phloem phloem phloem phloem phloem phloem phloem phloem phloem phloem fibres.

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Complex Tissues 

The complex tissues are the ones that consist of more than one type of cell which works together as a unit. The transportation of organic material, water, and minerals up and down the plants is done by complex issues. Therefore, they are also known as the Conducting and Vascular tissues. The complex tissues of a plant are responsible for transporting nutrients and water to the leaves, as well as eliminating photosynthetic products from the leaves. The sugar glucose is produced by photosynthesis. The material is modified and bonded to additional 6-carbon sugars to form sucrose or a number of different disaccharides. It can be transferred with a tiny amount of water and delivered efficiently throughout the plant in this state. The plant's complex tissues assist in this overall endeavour by providing food to the roots while also providing water and nutrients to the leaves.

What are the types of Complex Tissues?

Complex tissues are of two types as mentioned below:

Xylem 

Xylem is a type of vascular tissue found in plants that transport water and dissolved minerals from the roots to the rest of the plant while also providing physical support. Xylem tissue is made up of tracheary components, which are specialised water-conducting cells. All vascular plants, including seedless club mosses, ferns, and horsetails, as well as all angiosperms (flowering plants) and gymnosperms (woody plants), include xylem, which works in tandem with phloem (tissue that transports glucose from the leaves to the rest of the plant) (plants with seeds unenclosed in an ovary). Tracheids and vessel members, which are both narrow, hollow, and elongated, make up the xylem tracheary elements. Tracheids are the only water-conducting cells in most gymnosperms and seedless vascular plants, and they are less specialised than vessel members.

Phloem

The phloem is made up of living tissue that actively transports sugars to plant organs such as fruits, flowers, buds, and roots by using turgor pressure and energy in the form of ATP; the other substance that makes up the vascular plant transport system is the xylem. The phloem is made up of various different components. Each of the components works together to help sugars and amino acids go from a source to sink tissues, where they can be digested or stored.

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Difference Between Simple And Complex Tissue

The primary difference between simple and complex tissue is, simple tissue is made up of only one type of cell whereas complex tissue is formed of many types of cells. A simple tissue in animals is known as Epithelium whereas in plants it is known as Epidermis. Complex tissues are scattered everywhere in the body to hold all the organs together and support them. 

Functions of Tissues

Each tissue present in our body performs its specific functions which are generally reflected in the arrangement of the cells and their appearances. The basic function performed by the cells are the following. 

• secretion

• movement

• strength

• excretion

• Communication