Katie J. Field from the University of Sheffield in the United Kingdom and colleagues from the University of Cambridge and Abbey Brook Cactus Nursery in Derbyshire are the first to reveal the secrets of adaptation in South African “living stone” plants (Lithops species) that allow the pants to survive in the Oct. 23, 2013, edition of the journal Public Library of Science.
The species name Lithops comes from the Greek for stone face due to the plants resembling rocks. There are at least 400 different varieties of stone plants.
Most species of Lithops live totally or partially underground due to the arid environment that the plants populate.
The researchers found that the plants have adapted a unique structure and chemistry to produce photosynthesis with a limited amount of sunlight and to conserve water.
The plants have developed specialized translucent pockets on the top side of the plant that is exposed to light that allow the light needed for photosynthesis to penetrate to the underground leaf structures. Flavonoid pigments filter sunlight that could be harmful to the plant and assist in maximizing the amount of light needed for photosynthesis to be made available to the part of the plant parts that are underground.
Each species has developed different pigment adaptations for both high light and shade tolerance that minimize water loss and maximize photosynthetic food production. The specialized translucent windows that allow sunlight to be available to the underground part of the plants are the key to regional physiological differences in Lithops shape, cell structure, and depend on how much of the leaf is above or below ground.