The uptake of CO₂ from the air is an essential process of plant photosynthesis. In dry areas, some plants shift this process to the night so that they can keep their stomata closed during the day and thus reduce the evaporation of water. To do this, they possess a special photosynthesis mechanism (Crassulacean acid metabolism, CAM). The extent to which plants use this mechanism for their energy balance depends, in part, on the unpredictability of precipitation. Scientists from the University of Bayreuth, the University of Hohenheim, and Stellenbosch University in South Africa report on this in the journal „New Phytologist“.