Difference Between Symplast and Vacuolar Pathway

The key difference between symplast and vacuolar pathway is that in the symplast pathway, water does not enter into vacuoles while in the vacuolar pathway, water passes into vacuoles.

Water moves through plant cells, especially across the root, via three major pathways. They are apoplast, symplast and vacuolar pathways. In the apoplast pathway, water and dissolved ions move through the cell walls of cells. Therefore, water does not cross any membrane or cytoplasm in the apoplast pathway. In the symplast pathway, water moves through protoplasm from cytoplasm to cytoplasm via plasmodesmata, so water does not enter into vacuoles in the symplast pathway.  In the vacuolar pathway, water moves through the plasma membrane, cytoplasm and then through the vacuole.

CONTENTS

1. Overview and Key Difference
2. What is Symplast Pathway
3. What is Vacuolar Pathway
4. Similarities Between Symplast and Vacuolar Pathway
5. Side by Side Comparison – Symplast vs Vacuolar Pathway in Tabular Form
6. Summary

What is Symplast Pathway?

Symplast pathway is one of the three main routes of water movement in plants. In the symplast pathway, water moves from cytoplasm to cytoplasm via the plasmodesmata. Therefore, water does not cross the tonoplast or vacuoles of the cells. The water movement via the symplast pathway takes place by osmosis. And, this pathway uses the protoplasm of the cell.

Moreover, this is one of the main pathways by which water and nutrients reach the xylem of the plant from the soil via roots. Water moves freely through this pathway. Also, low molecular weight solutes such as sugars, amino acids and ions move between cells.

What is Vacuolar Pathway?

The vacuolar pathway is another route of water movement through plant cells. In the vacuolar pathway, water moves through the protoplasm. In other words, the water movement takes place via the cell walls, plasma membrane, cytoplasm, tonoplast and central vacuole. Since water passes through several parts of the plant cell in the vacuolar pathway, it provides a lot of resistance. Hence, it is not commonly used. It is used only when individual cells uptake water from the surrounding.

What are the Similarities Between Symplast and Vacuolar Pathway?

• Symplast and vacuolar pathways are two of the three main types of water movement pathways through plant cells.
• In both pathways, water passes through the cytoplasm of the cell.
• Water moves by the osmosis in both pathways.

What is the Difference Between Symplast and Vacuolar Pathway?

Symplast pathway is the movement of water molecules via the cytoplasms of plant cells while the vacuolar pathway is the movement of water molecules via the central vacuoles of plant cells. Therefore, in the symplast pathway, water does not enter the vacuoles while in the vacuolar pathway, water passes through central vacuoles. So, this is the key difference between symplast and vacuolar pathway.

Moreover, water moves from cytoplasm to cytoplasm via plasmodesmata in the symplast pathway. In contrast, water moves through the cell wall, plasma-lemma, cytoplasm, tonoplast and central vacuole in the vacuolar pathway. However, due to the high resistance posed by the vacuolar pathway, it is only used when individual cells uptake water. But, the symplast pathway is commonly used by plants for the water movements.

Below is a tabulation of the difference between symplast and vacuolar pathway.

Summary – Symplast vs Vacuolar Pathway

Symplast and vacuolar pathways are two of the three pathways by which water moves in plant cells. In the symplast pathway, water moves from the cytoplasm of one cell to the cytoplasm of the next cell through plasmodesmata. In the vacuolar pathway, water moves between vacuoles of cells crossing cytoplasms as well. Compared to the vacuolar pathway, the resistance is less in the symplast pathway, and plant cells use this pathway more frequently than the vacuolar pathway. Thus, this summarizes the difference between symplast and vacuolar pathway.

Reference:

1. “Movement Of Water In Roots: 3 Pathways (With Diagram)”. Biology Discussion, 2020, Available here.
2. “Symplast Pathway”. Embibe.Com, 2020, Available here.

Image Courtesy:

1. “Apoplast and symplast pathways” By Jackacon, vectorised by Smartse – Apoplast and symplast pathways.gif, (Public Domain) via Commons Wikimedia