How do cacti and other succulents store water?

Succulents are plants characterized by thick, fleshy tissues specifically adapted for water storage. While the exact location of this storage varies by species, cacti primarily store water within their stems, often having reduced or absent leaves to minimize water loss. Other succulents, such as agaves, store water mainly in their leaves.1

This storage capacity is facilitated by parenchyma, a versatile plant tissue composed of thin-walled, living cells that are capable of performing various functions, including storage.2

To survive in arid environments, many succulents also employ crassulacean acid metabolism. This adaptation involves keeping their stomata closed during the hot day to prevent transpiration and opening them only at night to collect carbon dioxide, significantly reducing water loss.1