The key difference between phragmoplast and cell plate is that phragmoplast is the complex arrangement of microtubules, microfilaments, Golgi derived vesicles and endoplasmic reticulum that gives rise to the cell plate, which is the flattened membrane-bound structure that works as the precursor of the new cell wall.
Cytokinesis refers to the division of the parental cell cytoplasm into two parts to form two new daughter cells. This process differs between the plant cells and animal cells due to the presence of a cell wall in plant cells. Therefore, in plant cells, cytokinesis occurs via the formation of a cell plate in the middle of the cell. There are several stages of cell plate formation. In the beginning, a phragmoplast (an array of microtubules) is formed. Then the vesicles (carrying components for cell wall synthesis) arrive at the division plane. Vesicles fuse to generate a tubular-vesicular network called a cell plate. Then the fusion of membrane tubules continues. Next, it transforms into a membrane sheet. After that, the deposition of cellulose takes place. Moreover, the recycling of excess membrane and other material from the cell plate takes place. Finally, the newly forms cell wall fuses with the parental cell wall, resulting in the separation of two new daughter cells.
CONTENTS
1. Overview and Key Difference
2. What is Phragmoplast
3. What is Cell Plate
4. Similarities Between Phragmoplast and Cell Plate
5. Side by Side Comparison – Phragmoplast vs Cell Plate in Tabular Form
6. Summary
What is Phragmoplast?
Phragmoplast is a plant cell-specific structure that gives rise to the cell plate. It is a complex arrangement of microtubules, microfilaments, Golgi-derived vesicles, and endoplasmic reticulum. It forms during the late anaphase of the cell division. Once formed, it works as a framework for cell plate assembly and the formation of a new cell wall separating the two daughter cells. After the formation of a new cell wall, phragmoplast structure is dismantled. Hence, the importance of phragmoplast in plant cells is that it mediates the cytokinesis via the formation of a cell plate.
Figure 01: Phragmoplast and Cell Plate Formation in a Plant Cell During Cytokinesis
Structurally, phragmoplast is a barrel-shaped or cylindrical structure with a black line across the midzone. It possesses two opposing arrays of actin filaments and microtubules with their plus ends facing towards the midzone.
What is Cell Plate?
The cell plate is the flattened membrane-bound structure that forms between two groups of chromosomes in a dividing plant cell. It works as the precursor for the new cell wall that is developing in order to separate two daughter cells. The cell plate develops as a result of the fusion of small Golgi derived vesicles that coalesce in the midzone. Therefore, vesicles contribute their membranes to form cell membranes and the matrix contents to form the cell wall. Gradually, the cell plate extends until it fuses with the sides of the parent cell wall. It happens due to the fusion of more vesicles at the midzone. At last, the newly formed cell wall separates the two new daughter cells.
Figure 02: Cell Plate and Phragmoplast
Moreover, cellulose synthesis takes place in the cell plate and the cell plate totally transforms into a primary cell wall at the end of the cytokinesis. However, there are plasmodesmata between the two newly formed daughter cells. Most importantly, phragmoplast is the structure that gives rise to the cell plate. Therefore, the formation and growth of the cell plate are dependent upon the phragmoplast.
What are the Similarities Between Phragmoplast and Cell Plate?
- Phragmoplast and cell plate are two plant cell-specific structures formed during cytokinesis.
- Both are cytoplasmic structures.
- Phragmoplast is the structure that gives rise to the cell plate. Therefore, the formation and growth of the cell plate are dependent on phragmoplast.
- Both phragmoplast and cell plate are essential in the formation of a new cell wall of dividing plant cells.
- They are formed at the equator of the spindle after chromosomes have divided during the anaphase of plant mitosis.
What is the Difference Between Phragmoplast and Cell Plate?
Phragmoplast and cell plate are two plant cell-specific structures. Phragmoplast is a complex arrangement of microtubules, microfilaments, Golgi-derived vesicles, and endoplasmic reticulum that gives rise to the cell plate during the cytokinesis. Meanwhile, cell plate is the disk-shaped membrane-bound structure that is the precursor for the formation of new cell wall between two daughter cells. So, this is the key difference between phragmoplast and cell plate. Furthermore, the phragmoplast is barrel-shaped, but the cell plate is flattened and disk-shaped. Thus, this the structural difference between phragmoplast and cell plate.
Moreover, phragmoplast is found only in phragmoplastophyta, but cell plate is common in terrestrial plants and some algae.
The below infographic summarizes the difference between phragmoplast and cell plate.
Summary – Phragmoplast vs Cell Plate
Cytokinesis is the final process of cell division in which parental cytoplasm divides into two parts by separating cytoplasmic organelles and duplicated genomes in order to form two daughter cells. Plant cell cytokinesis occurs via the formation of a cell plate. A plant cell-specific structure called phragmoplast gives rise to the cell plate. Phragmoplast serves as a scaffold for cell plate assembly. Cell plate is the flattened membrane-bound structure develops in the middle plane of the dividing cell that works as the precursor for the new cell wall. It forms by the fusion of Golgi derived vesicles in the cytoplasm. So, this is the summary of the difference between phragmoplast and cell plate.
Reference:
1. Otegui, Marisa S, et al. “Midbodies and Phragmoplasts: Analogous Structures Involved in Cytokinesis.”Trends in Cell Biology, U.S. National Library of Medicine, Aug. 2005, Available here.
2. “Cell Plate.” Wikipedia, Wikimedia Foundation, 16 Apr. 2019, Available here.
Image Courtesy:
1. “Phragmoplast” By Tameeria at English Wikipedia – Transferred from en.wikipedia to Commons by Vojtech.dostal (Public Domain) via Commons Wikimedia
2. “Microtubules in plants diagram” By BlueRidgeKitties (CC BY 2.0) via Flickr