Differences Between Apoplast and Symplast – Imaluop

Hi, now we will discuss basic differences between apoplast and symplast with similarities between apoplast and symplast. 

What is Apoplast: 

Plant tissue is formed by plant cells and different materials produced by the cells among which some are living substances while some are non-living. Different terms are used for the two types of components in a tissue, the non living material present outside of plasma membrane in plant tissues are known as apoplast.

Most of the material like water can easily pass through the apoplast portion of tissues in the plant. The transport of water and other solutes through the apoplast portion of tissues is known as apoplastic transport. 

What is Symplast: 

From the cell membrane living substances present in a plant cells and the living portion in a plant tissue are known as symplast. The pathway of water and other solutes through the plasma membrane is known as the symplastic pathway.

The symplastic pathway is often referred to as the transmembrane pathway because it involves crossing the cell plasma membrane and most of the substrates are not permitted in the symplastic pathway. 

Differences Between Apoplast and Symplast: 

Apoplast	Symplast
In a plant tissue apoplast suggests non protoplasmic substances and the components outside the plasma membrane like cell wall and intercellular space.	In a plant tissue Symplast suggests all living portions of tissues like protoplasm inside plasma membrane and the plasmodesmata which make the living connection between different cells.
As apoplasts represent non living parts of plant tissue and permeable for most of the solutes so transport in an apoplastic pathway occurs generally through the process of diffusion.	Symplastic pathways do not allow all solutes and it is bordered by plasma membranes so transport in apoplastic pathways occurs through osmosis.
In apoplastic pathway water transport at a very fast rate because transport faces less restrictions.	In symplastic pathways water takes a long time for transport because transport does not occur by simple diffusion.
Apoplast is the result of the components formed by the cells which are not living and do not contain different cell organelles.	Symplast is the main active portion of plant tissue where most of the cell organelles present and most of the cellular metabolism occurs.

Similarities Between Apoplast and Symplast:  

Both apoplast and symplast present inside the cortex area of root in higher plants. 

Both apoplast and symplast are two paths which are options for entry of water and other solutes from root hairs to vascular tissue of plants. 

Apoplastic Pathway: 

When water reaches from outside of the root to xylem water needs to cross different components of a tissue. Water passes easily through the cell walls of the plant tissues by the process of diffusion.

But water can not reach upto xylem tissue through the apoplastic pathway because when water reaches the endodermis layer, the casparian strips present on the endodermis prevent the water to transport further.

Then water transport through the symplastic pathway by the process of osmosis and reach upto xylem tissue of root. Transport of water and other solutes through the apoplastic pathway is hardly affected by metabolic state of the root tissue because apoplastic pathways contain non-living portions of tissues.

Symplastic Pathway: 

Water transport through the living part of tissues faces more resistance than the apoplastic pathway which is affected by metabolic state of root tissues. Water takes most of the time for transport during the symplastic pathway because they need to cross through the plasma membrane which does not occur by simple diffusion easily.

So when water enters through the tissue to reach the xylem tissue, water needs to pass through the both pathway, apoplastic pathway and symplastic pathway.

Reference: Differences Between Apoplast and Symplast

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