Glow-Orb Cactus
A relative to the Lantern plant is the Glow-Orb Cactus.

It is a small, ground-hugging succulent perennial that, as it reaches maturity, produces a helium-filled sac. The helium is siphoned out of the air (where it exists in minute amounts) by specialized pore-proteins on the surface of the sac. When fully inflated the bladder deploys on a 2-metre long umbilical cord.

The cells that make up the sac membrane produces a protein called luciferin, commonly found in glow-worms, that convert chemical energy (ATP) into light. The orb starts to glow with a clear, steady and greenish-tinted shine. There are both garden and indoor versions, with orbs varying in size from a few centimeters to nearly a meter in diameter.

The helium-siphoning gene that allows the cactus to extract the element from the air is vectored into the plant from the human genome, where it exists naturally. It is involved in regulating the gaseous exchange in the alveoli of the baseline human lung. Carbon dioxide is transported out of the bloodstream partly due to antiportal exchange with helium. The formation of a gas-filled sac in the first place is a characteristic borrowed from certain kinds of terrestrial seaweed, which does this to catch the sunlight in shallower waters.
 
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Development Notes
Text by David Hallberg

Initially published on 31 October 2001.