Yes, stomata can be kidney-shaped.
Stomata, the tiny pores on the surface of plant leaves (and sometimes stems), are bordered by specialized cells called guard cells. These guard cells control the opening and closing of the stomata, regulating gas exchange (carbon dioxide intake and oxygen release) and water transpiration.
While some plants possess stomata with dumb-bell shaped guard cells (as is common in grasses and wheat), many other plants exhibit kidney-shaped guard cells. This kidney shape is crucial to the mechanism by which the stomata open and close. The turgor pressure within the guard cells changes, causing them to bend and create an opening (the stoma) between them.
In summary, stomata can indeed be kidney-shaped, and this shape plays a vital role in their function.
