As land plants undergo cell division, a Cell Plate structure is formed within their cells. Land plant cells are unique because they have a cell wall made of rigid sugars surrounding their cell membranes, unlike animal cells.
Besides protecting the cell from injury, these cell walls support the plant’s rigid upright structures, such as stems and leaves.
The plant’s ability to grow tall and wide, reaching for more sunlight, is attributed to these rigid support structures. Most plants’ cell walls are composed of cellulose, a rigid surface formed by an arrangement of glucose molecules.
Notably, cellulose in the cell wall is not digestible by humans or animals, but certain methane-producing archaebacteria can break it down into sugar. This is one reason why many animals have a symbiotic relationship with archaebacteria in their gut.
A new cell wall separates the daughter cells during cell division in plants. This newly formed cell wall must be positioned in the middle of the parent cell to ensure that each side of the cell wall receives an equal amount of the parent cell’s chloroplasts, gene copies, and other essential components.
The cell plate is the complex sugar “plate” that forms in the middle of the parent cell, eventually developing into the cell wall of the future daughter cells.
The cell plate is formed when vesicles carrying phospholipids required to form the cell membrane and sugars needed to build the cell wall are transported and assembled through a network of cytoskeleton spindle fibres that forms in the middle of the cell as it prepares to divide.
Structure of Cell Plate:
The cell plate is a disc-like structure that forms between the two nuclei of a dividing cell. The cell plate comprises several layers of membrane-bound vesicles containing cell wall materials such as cellulose, hemicellulose, and pectin. The cell plate also contains various proteins, including enzymes in cell wall synthesis and cytoskeleton components.
Formation of Cell Plate
Cell plate formation is a complex process that occurs during cytokinesis in plant cells. This process involves the formation of a new cell wall that separates the two daughter cells. The following is a detailed explanation of cell plate formation with headings.
Initiation of cell plate formation
Cell plate formation is initiated after the chromosomes have been separated into two nuclei during mitosis. At this stage, a phragmoplast structure forms in the centre of the cell. The phragmoplast comprises microtubules and serves as a scaffold for the movement of Golgi vesicles toward the centre of the cell.
Movement of Golgi vesicles
Golgi vesicles transport the components necessary for cell wall formation, including cellulose and pectin. These vesicles move along the microtubules toward the centre of the cell, guided by the phragmoplast.
Fusion of Golgi vesicles
Once the Golgi vesicles have reached the centre of the cell, they begin to fuse together to form a disc-shaped structure called the cell plate. As the vesicles fuse, they deposit their contents, including cell wall components, into the growing cell plate.
Growth of the cell plate
The cell plate continues to grow outward from the centre of the cell, depositing more cell wall components as it expands. As the cell plate grows, it eventually reaches the existing cell walls on either side of the dividing cell.
Fusion of the cell plate with the existing cell walls
The final step in cell plate formation is the fusion of the cell plate with the existing cell walls. The cell plate fuses with the existing cell walls, forming a complete cell wall that separates the two daughter cells.
Functions of Cell Plate
The cell walls of plants have a dual role: protecting the valuable contents of plant cells, such as the nuclei, and providing structural support for the plant’s free-standing form.
Animals and plants lack skeletons and must rely on their parts, such as stems and leaves, to stand upright against the force of gravity. Therefore, cell walls are a crucial component of land plants, but they may not be present in ocean plants, which live in a weightless environment, or animals with skeletons.
However, cell walls present a challenge for cell division in plants. When cells without cell walls divide to produce daughter cells, they pinch their cell membrane in the middle. The cell membrane is flexible and can be pinched and reshaped as needed to alter the cell’s shape.
In contrast, the rigid cell wall cannot be easily pinched or bent. This restricts the cell’s shape during reproduction and makes cytokinesis, the process of cell division, more complex.
To overcome this challenge, plants must generate a new section of the cell wall during cytokinesis to ensure that their daughter cells possess the structural integrity required to maintain the plant’s form. This process involves a series of steps that we will discuss below.
Factors That Affect Cell Plate Formation
The development of the cell plate can be affected by various factors. These characteristics include the location of the spindle fibres while the cell is undergoing mitosis, the presence of the Golgi apparatus, and the cytoskeleton. Hormones and other signalling molecules can also affect the development of the cell plate.
FAQs
Ans: Cytokinesis is the final stage of cell division, which involves physically separating the two daughter cells. In animal cells, cytokinesis involves the formation of a cleavage furrow, while in plant cells, it involves the formation of a cell plate.
Ans: A disc-like structure in the plane of the spindle’s equator separates the two sets of chromosomes during cytokinesis and also creates the cell wall between the two daughter cells after cell division.
Ans: The cell plate is important because it is a structure that develops during plant cell division and finally becomes a new cell wall that separates the daughter cells. This process, known as cytokinesis, is necessary for forming and proliferating plant tissues and organs. Without the cell plate, daughter cells would not be able to split properly, and the plant would be unable to develop and function normally.
Ans: The cell plate comprises a new cell membrane and cell wall material deposited in the centre of the dividing cell during cytokinesis.
Ans: Yes, the cell plate is a unique structure that is found only in plant cells.
Ans: Without the cell plate, the two daughter cells would remain connected and unable to function independently, severely impacting plant growth and development.
Ans: Yes, the cell plate is found in all plant cells that undergo cytokinesis.
References and Sources:
- Molecular Biology of the Cell – by Bruce Alberts
- https://biologydictionary.net/cell-plate/
- https://www.differencebetween.com/what-is-the-difference-between-cell-plate-and-metaphase-plate/
- https://study.com/learn/lesson/cell-plate-overview-formation.html
- https://en.wikipedia.org/wiki/Cell_plate
- https://www.britannica.com/science/cell-biology/Cell-division-and-growth
- https://brainly.in/question/8270482