How the ice plant thrives in high-salt areas

Plants need water, but if that water also comes with a hefty dose of salt it can kill the plant. But the ice plant, Mesembryanthemum crystallinum, has a clever way of storing salt in special cells, allowing it to thrive in saline coastal areas.

“We want to understand why crop plants aren’t very salt-tolerant. The ice plant—which is a halophyte, meaning it actually grows better in the presence of salt—is a great model to study,” says Associate Professor Bronwyn Barkla of Southern Cross University, who led the research.

She noticed the plant has modified versions of the hair-like structures found on the leaves of most plants (think of tomatoes). Known as epidermal bladder cells, these accumulate salt from the water the plant absorbs.

“These cells are quite large, and they can accumulate salt (sodium), at a concentration of up to 1.2 molar—from the ones we’ve measured so far. Seawater is around 450 millimolar sodium, so it’s quite a large amount.”

The plant may also be useful in phytoremediation—using plants to clean up land and make it productive again.

“For example, you might grow the plant on land that’s been salinised due to over-cropping and irrigation, and harvest them before they die and release their salt back to the soil,” Bronwyn says.

She’s also working with an industry partner looking at developing an edible line of these plants. She says they’re quite tasty and crunchy, and have become popular as a gourmet salad item in China.

Part of this research was published in BMC Plant Biology in 2016.

Bronwyn’s work has helped reveal the role of these cells in salt tolerance and plant metabolism. Credit: Omar Pantoja