How succulents are so efficient with water

New research on succulents could help boost crop production in drought-prone regions.

Succulents are an increasingly popular houseplant due to their incredible efficiency with water, which makes them especially easy to care for.

Succulents, cacti, and agaves are all considered drought-resistant because they use a special type of photosynthesis that conserves water called crassulacean acid metabolism (CAM).

Succulents and other CAM plants harvest carbon dioxide and stores it overnight. This stored CO2 is then used during photosynthesis the next day.

CAM photosynthesis is dependent on the plant’s internal circadian clock.

A new study conducted by plant scientists at the University of Liverpool examined this unique photosynthesis in succulents to see what genetic factors were at work during the CAM process.

For the study, the researchers focused on an enzyme called PPCK. PPCK is used to convert CO2 that is stored overnight into malic acid and then back to CO2 the next day. This process is integral to CAM photosynthesis.

The researchers were able to effectively switch off the PPCK gene in a succulent plant called Kalanchoë fedtschenkoi to see how this affected the CAM process.

Without PPCK, the succulent wasn’t able to perform the CAM process properly and only stored one-third of the CO2 that most other plants store.

The results also showed that switching off the PPCK gene interfered with the plant’s circadian clock.

The researchers were able to gain insight into the CAM process, but further research is necessary in order to fully understand the roles that CAM photosynthesis and the PPCK gene play in water conservation in CAM plants.

“Our work demonstrates that ongoing efforts to engineer CAM photosynthesis into other plants will need to include PPCK,”  said Dr. James Hartwell, one of the authors of the study. “The unexpected complexity we revealed in the relationship between PPCK, CAM, and the circadian clock also highlights the need for continued research into CAM processes before we can fully understand and exploit their ways.”

The researchers hope by examining the CAM process further, it will help enhance global agriculture by producing crops that can thrive in hot, arid, regions.

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By Kay Vandette, Earth.com Staff Writer