The barrier that forms between two new daughter cells just before cytokinesis in plant cells is called the cell plate.

Here's how it works:

* Formation: The cell plate starts forming during telophase of mitosis, as the nuclear envelope reforms around the separated chromosomes.

* Vesicles: Small membrane-bound vesicles containing cell wall material (cellulose, pectin, etc.) from the Golgi apparatus move to the center of the cell, where they fuse together.

* Growth: The cell plate grows outward, eventually merging with the existing cell wall. This divides the cytoplasm into two distinct daughter cells.

Key difference from animal cells: Unlike animal cells that form a cleavage furrow during cytokinesis, plant cells have a rigid cell wall, making this furrow formation impossible. The cell plate is a unique adaptation that allows for cell division in plants.