Image of the Day: Puzzle Plants

The jigsaw-shape cells found in the epidermis of many plants may serve to reduce mechanical stress on cell walls.

Mar 19, 2018
The Scientist Staff

Relationship between cell shape and stress: (A) Cell contours in leaf cells of an Arabidopsis thaliana cotyledon. (B-F) Cellular stress patterns in computer simulations. (G) Measures used to quantify puzzle-cell shape and stressA. SAPALA ET AL.

Scientists have long puzzled over the erratically contoured cells in the outer layers of plants. According to a study published last month in eLife, the complex shapes may emerge to prevent cells from bulging under the internal stress produced by turgor pressure.

Researchers simulated plant cell growth with computer models and found that “paving” leaf surfaces with curvy cells, rather than smooth ones, reduces the stress on epidermal cell walls. They also found that complex puzzle-shape cells develop in parts of the plant that grow isotropically—uniformly in all directions—such as in leaves. In organs that grow directionally, such as roots or stems, cells that are long and thin can reduce stress on the cell walls.

A. Sapala et al., “Why plants make puzzle cells, and how their shape emerges,” eLife, doi:10.7554/eLife.32794, 2018.