Lithops and other succulents conserve water using many ingenious methods. They can quickly grow fine roots to pull infrequent rain into their succulent leaves. They use CAM photosynthesis to prevent water loss. They have tough skins that resist evaporation. They can be dormant for months and need no moisture at all. They can use their longer taproots to literally pull themselves underground.
But how do Tillandsias do it? Well, they also use CAM photosynthesis. But Tillies have a unique contraption to hold and keep water. The trichome.
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| from Bromeliad.org.au |
Many plants other than bromeliads use a variety of trichomes for a variety of functions, but the Tillandsia trichomes are my subject today. They look like flowers or shields on the surface of the leaves. The top-facing trichomes are different from those on the undersides of leaves. Tillandsias facing more sun and drought have more of them, and are more silvery/fuzzy as a result. Shady Tillies that are used to more moisture have fewer trichomes, and they look more green and smooth.
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| from botany.cz |
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| T. magnusiana has lots of trichomes! |
Tillandsia trichomes can open and close like trapdoors. They can reflect up to 45% of sunlight, keeping the plant cool and moist, and they can quickly pull in water from either fog or rain. When this happens, they essentially "lock" to prevent the water from escaping. The plant turns green, and soaks up some sun. Good air circulation resets the trichomes and the cycle can begin again. Amazing!
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| A mix of Tillies, a mix of trichomes. |
