What is the Difference Between Perforation Plates and Sieve Plate

The main difference between perforation plates and sieve plate is that perforation plates contain actual holes, whereas sieve plates do not contain actual holes.

Perforation plates and sieve plates are two openings that occur in the xylem and phloem of plants. They facilitate the conduction of water and food through the cell. 

Key Areas Covered

1. What are Perforation Plates
– Definition, Structure, Function
2. What is Sieve Plate
– Definition, Structure, Function
3. Similarities Between Perforation Plates and Sieve Plates
– Outline of Common Features
4. Difference Between Perforation Plates and Sieve Plates
– Comparison of Key Differences

Key Terms 

Perforation Plates, Sieve Plate

What are Perforation Plates

Perforation plates are openings that occur in the vessel elements of the xylem. Importantly, perforation plates occur in the vessel elements. On the other hand, the xylem is the water-conducting tissue of the plant from the root to the shoots. Also, two cell types are involved in water conduction in the xylem. They are vessel elements and tracheids. Vessel elements occur in angiosperms but not in gymnosperms like conifers. They are the major component of the hardwood. However, vessel elements are the building blocks of xylem vessels. They are long cells derived from the vascular cambium.

Figure 1: Perforation Plate

Furthermore, vessel elements orient on the axis of the stem. Also, the walls of vessel elements are lignified. The side walls of the vessel element contain pits that are circular regions contacting neighboring cells. The peroration plate is the end opening of the vessel elements. It occurs in various shapes. Simple openings are the most common type of perforation plates. The scalariform perforation contains several elongated, ladder-like openings. On the other hand, the foraminate perforation plate contains several rounds of openings. Also, the reticulate perforation plate contains a net-like many openings. 

What is Sieve Plate

A sieve plate is an opening that occurs in the sieve elements of the phloem. Sieve elements occur in angiosperms. Two types of cells occur in the sieve element. They are sieve tube cells and companion cells. They are connected through plasmodesmata that contain channels between cell walls. The cell walls of the sieve tube elements disperse with plasmodesmata and develop into sieve plates over time. Sieve elements are long, horizontal cells. They contain sieve plates that have sieve pores.

Figure 2: Sieve Plate

Importantly, the size of the sieve pores can be regulated. Also, sieve plates are large, having the greatest surface area to transport materials. Moreover, sieve tubes form by an end-to-end longitudinal arrangement of sieve elements. 

Similarities Between Perforation Plates and Sieve Plates

• Perforation plates and sieve plates are two openings that occur in conduction tissue.
• They occur in angiosperms.

Difference Between Perforation Plates and Sieve Plates

Definition

Perforation plates refer to the end wall of a vessel element, with one or more openings (perforations) to allow the passage of water and dissolved substances. In contrast, a sieve plate refers to the connection site between sieve elements. 

Occurrence

The perforation plate occurs in the xylem, while the sieve plate occurs in the phloem. 

Living or Non-Living

The perforation plate is a nonliving part, while the sieve plate is a living part.  

Conduction

The perforation plate conducts water, while the sieve plate conducts food. 

Openings 

The perforation plates contain actual holes, while sieve plates do not contain actual holes.

Conclusion

In brief, perforation plates and sieve plates are two plates that contain openings to conduct substances through the plate. Perforation plate occurs in the xylem, and it is non-living. It conducts water through it. Importantly, it contains actual holes that conduct water. On the other hand, a sieve plate occurs in the phloem and is, therefore, a living cell. It conducts food through the stem. However, it does not contain actual holes. They are protoplasmic connections lined with the plasma membrane. Therefore, the main difference between a perforation plate and a sieve plate is the type of openings. 

References:

1. Wikimedia Foundation. (2023j, May 6). Vessel element. Wikipedia. 
2. Wikimedia Foundation. (2022c, September 18). Sieve tube element. Wikipedia. 

Image Courtesy:

1. “Hardwood Pores” By Mckdandy – Own work (CC-BY 2.5) via Commons Wikimedia
2. “Sieve tube member.” By Manvita12345 – Own Work (CC-BY SA 4.0) via Commons Wikimedia