Cell migration in gastrulation

Selective death of cells, tissues and organs is an essential feature of plant development and survival. Elementary mathematics illustrates why this is so. Consider a spherical group of cells, where the radius of the sphere is r. Its volume is 4/3πr³ and its surface area is 4πr². With increasing numbers of cells, and therefore size of sphere, the volume increases as the cube of the radius, whereas the increase in surface area is proportional only to r².



Exchange of materials essential for cell growth and survival - respiratory gases, nutrients - is dependent on the area of contact between cells and the environment. For a group of cells to develop any degree of size and structural complexity requires penetration of the cell mass by holes or tubes, to ensure surface area keeps pace with volume, thereby facilitating vital transport and exchange processes. In animal embryogenesis, holes and tubes are often formed by cell migration, such as occurs in gastrulation.

Links and further reading

• Illustrations, streaming movies and information linked to Stern CD (2004) Gastrulation: From Cells to Embryo. Cold Spring Harbor Laboratory Press are here.
• Gastrulation animation on YouTube.
• This cartoon of floral reproduction, including pollen tube growth, is on the UC Davis Web Course Biological Science 10V