The cell plate is a temporary structure that forms within dividing plant cells, and some algae, during the final stage of cell division called cytokinesis. Its main purpose is to construct a new cell wall that separates the two newly formed daughter cells. This process is fundamental for plant growth and development, ensuring that new cells are properly partitioned with their own structural boundaries.
How the Cell Plate Forms
The cell plate’s formation is guided by a structure called the phragmoplast, which is an assembly of microtubules and microfilaments that forms between the two sets of separated chromosomes. This phragmoplast acts as a scaffold, directing vesicles to the equatorial plane of the dividing cell.
These vesicles originate from the Golgi apparatus and are filled with components necessary for building a new cell wall, such as polysaccharides like cellulose and pectin. The vesicles travel along the microtubules of the phragmoplast and begin to fuse in the center of the cell, forming a disc-shaped structure. As more vesicles arrive and fuse, this initial structure expands outwards from the center towards the original cell walls, creating a new cell wall between the two daughter cells.
The Cell Plate’s Crucial Role
The cell plate establishes a new cell wall that divides the parent cell into two daughter cells. This new cell wall provides structural integrity and protection to the new plant cells. It maintains the shape and rigidity of plant tissues.
This process ensures that each new cell receives its own complete boundary, allowing for growth and development within the plant. The precise placement and maturation of the cell plate are important for the development of plant tissues and organs. Without this structured division, plant growth would be affected.
Cell Plate Versus Cleavage Furrow
The mechanism of cell division in plant cells, involving the cell plate, differs from that in animal cells, which utilize a cleavage furrow. The presence of a rigid cell wall in plant cells prevents them from pinching in half. Instead, the cell plate forms internally and grows outward to divide the cell.
In contrast, animal cells, lacking a cell wall, form a cleavage furrow. This furrow is an indentation that appears on the cell surface and deepens as a contractile ring of actin and myosin filaments tightens. This ring pinches the parent cell into two daughter cells from the outside inward. While both structures achieve cytokinesis, the cell plate builds a new wall from the inside, while the cleavage furrow constricts the cell membrane from the outside.