In this article, we will discuss about the Difference Between Apoplast And Symplast Pathways. There are two types of transport pathways for the conduction of the water from one region to another. The path followed by the water can be Symplast or Apoplast pathway.
The Symplast is the pathway in which the water molecules move through the plasmodesmata region in the cells. The Symplast is the living region present between two cells that connect one cell with the other.
The Apoplast pathway is the path in which the water is moving between the intercellular spaces. The Apoplast includes the non-living spaces between cells and the cell membrane.
Both pathways are involved in the movement of water across the root. Water flows via the Apoplast in the cortex. It enters the Symplast pathway in the endodermis where walls are impervious to the flow of water due to the presence of Casparian strips.
What is Symplast Pathway?
The symplast pathway is the pathway through which water and solutes move through the cytoplasm and cell-to-cell connections of plants. It is important for the distribution of water and nutrients throughout the plant and the movement of signaling molecules and hormones.
The symplast pathway involves the movement of substances through plasmodesmata, which are small channels that connect the cytoplasm of plant cells to each other. Plasmodesmata allow for the movement of substances between cells without crossing the cell membrane, and can be selectively permeable, meaning that they can allow certain substances to pass through while preventing others from passing through.
The symplast pathway is active, meaning that it requires energy to move substances through it. It is also selective, meaning that only certain substances can pass through the cytoplasm and cell-to-cell connections. This allows the plant to control which substances are transported and where they are transported to.
The symplast pathway is important in the transport of substances in the phloem, which is the tissue responsible for the transport of sugars and other substances from the leaves to the rest of the plant. It is also important in the distribution of water and nutrients throughout the plant, as substances can move through the symplast pathway from cell to cell and reach different parts of the plant without having to move through the apoplast pathway.
Overall, the symplast pathway plays an important role in the distribution and transport of substances in plants, and is essential for the proper functioning and growth of the plant.
Apoplast Pathway
Apoplast is the pathway through which water and solutes move through the cell wall and extracellular space of plants. It is an important route for the absorption and transport of water and nutrients in plants and plays a key role in the proper functioning and growth of the plant.
The apoplast pathway begins in the root hairs, which are small, hair-like extensions of the root that increase the surface area for absorption. Root hairs absorb water and nutrients from the soil through a process called diffusion, which is the movement of substances from an area of higher concentration to an area of lower concentration.
Once water and nutrients are absorbed by the root hairs, they move through the cell walls of the root cells and into the extracellular space, which is the space outside the cells but within the plant tissue. From there, the substances move through the cell walls of the cells in the root and into the extracellular space of the stem, where they are transported upwards through the plant.
The apoplast pathway is passive, meaning that it does not require energy to move substances through it. However, it is slower than the symplast pathway, which is the pathway through which water and solutes move through the cytoplasm and cell-to-cell connections of plants, because it involves a longer route.
In addition, the apoplast pathway is not selective, meaning that any substance that can pass through the cell wall and extracellular space can move through it. This can be both an advantage and a disadvantage, as it allows for the movement of a wide range of substances, but also means that the plant cannot control which substances are transported.
Apoplast pathway vs Symplast pathway
- The apoplast pathway is the pathway through which water and solutes move through the cell wall and extracellular space of plants, while the symplast pathway is the pathway through which water and solutes move through the cytoplasm and cell-to-cell connections of plants.
- The apoplast pathway is slower than the symplast pathway because it involves the movement of water and solutes through the cell wall and extracellular space, which is a much longer route than the direct route through the cytoplasm and cell-to-cell connections provided by the symplast pathway.
- The apoplast pathway is not selective, meaning that any substance that can pass through the cell wall and extracellular space can move through the apoplast pathway. In contrast, the symplast pathway is selective, meaning that only certain substances can pass through the cytoplasm and cell-to-cell connections.
- The apoplast pathway is important for the movement of water and nutrients in plants, while the symplast pathway is important for the movement of signaling molecules and hormones.
- The apoplast pathway is not involved in the movement of substances across cell membranes, while the symplast pathway involves the movement of substances across cell membranes through plasmodesmata.
- The apoplast pathway is important for the absorption of water and nutrients from the soil, while the symplast pathway is important for the distribution of water and nutrients throughout the plant.
- The apoplast pathway is passive, meaning that it does not require energy to move substances through it, while the symplast pathway is active, meaning that it requires energy to move substances through it.
- The apoplast pathway is less efficient than the symplast pathway because it involves a longer route and is not selective, while the symplast pathway is more efficient because it involves a shorter route and is selective.
- The apoplast pathway is less important in the transport of substances in the xylem, while the symplast pathway is important in the transport of substances in the phloem.
- The apoplast pathway is important in the movement of water and nutrients from the roots to the shoots, while the symplast pathway is important in the movement of sugars and other substances from the leaves to the rest of the plant.
Frequently Asked Questions
Ans: In the apoplast pathway, the water moves through the adjacent wall of the epidermis and cortex without entering the cytoplasm.
Ans: The apoplast is the system of adjacent, continuous cell walls. It refers to the space outside the plasma membrane within which the molecules can freely diffuse.
Ans: The apoplast is the passive absorption that takes place through the apoplast of the root that comprises cell walls and intercellular spaces.
Ans: The Casparian strip is a band of waterproof tissue found on the sidewalls of the endodermis of roots. The strip prevents water from entering the pericycle that is important in inducing root pressure.
Ans: The symplast pathway is the pathway through which water and solutes move through the cytoplasm and cell-to-cell connections of plants. It is important for the distribution of water and nutrients throughout the plant and the movement of signaling molecules and hormones.
Read also
Refrences:
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