Ice Plant: Last Resort against Desertification
By studying a salt-loving plant in desert called ice plant, a professor and a
researcher from Saga University, located in western Japan, have been working to discourage
desertification in China and produce a new local agriculture product.
By Yas Mamemachi
Close-up photo of ice plant|
(Photo provided by Professor Nose and Shimoda)
n 1985 a young researcher, Akihiro Nose, was working in the desert near San Diego (California, USA). He took a handful of ice plant out of the desert. Ice plant, which originated in the Namib Desert in South Africa, was carried to North America in the 15th to 17th centuries and made its habitat in the New World.
Some plants living in desert, such as ice plant, survive there in a unique way, taking in carbon dioxide at night and storing it in the form of malic acid. Then, under daylight, the plant takes out carbon dioxide, which is stored as malic acid, and uses it for photosynthesis.
Nose thought that the more carbon dioxide stored inside the plant, the sharper the acid flavor of the plant. He wondered how sharp the acid flavor would be and bit into a piece of the plant, and was surprised to realize that it was rather salty, making the young researcher even more interested in the plant.
The plant has been on his mind ever since, though he did not conduct further research on how the plant absorbs salt and what amount of salt is stored in the plant at the time.
Time passed. A university professor (Dean, professor of School of Agriculture, Saga University), Nose's laboratory had been engaged in a Japanese environmental ministry’s research project on soil that deteriorates because of salt accumulation around the Aral Sea from 1996 to 1998. The project concluded that the leaching of salt from the surface of soil into the ground, which was locally introduced some time ago, works temporarily because saline groundwater rises up to the surface again once water on the surface evaporates.
The salt accumulation on the surface of the ground is the number one cause of desertification in many places in the world because almost no plants grow on the salty soil.
“Almost--,” Nose was wondering. Then, he remembered ice plant.
Salt loving plant
In 1999, one year after the Ministry of the Environment’s project was terminated, a junior student, Toshifumi Shimoda, started working on his graduation thesis with Nose as his advisor.
The professor explained to him about ice plant, asking if he would be interested in working on basic studies on the plant for his graduation thesis. He added that the studies would be a big help for the professor’s research work on the plant. Shimoda agreed, and Professor Nose and Shimoda have since started a joint research project on ice plant.
Professor Nose (right) and Shimoda with ice plant
(Photo provided by Professor Nose and Shimoda)
Under advice from the professor, Shimoda has cultured the plant in water for two years, revealing eye-opening traits of the plant.
“One of the most surprising things is that ice plant loves salt,” says Shimoda. “Most plants can hardly survive with 0.6% saline, however, ice plant grows more than double in size under the condition of one-forth or even a half of sea water concentration.”
They made the plant dry and analyzed the contents of the dry plant. As a result, about one-third of the dry plant was taken up by salt.
Nose points out two possible reasons why ice plant made such progress in the process of evolution. “One of the reasons is to expand the dominant territories of ice plant,” says the professor. “Since it is an annual, the plants that die about one year fall down on the ground. The ground where the plant dies down is covered with salt, rejecting other plants. So, land dominated by ice plants expands.”
“The other is to absorb water in the desert, a place with little water, where ice plant makes their habitat,” he continues. “Ice plant stores salt, keeping higher osmotic pressure in the plant. As a result, the plant can easily absorb water by osmotic water shift.”
A plant that can live in sea water may remind some people of mangrove, another unique plant that dominates coastal areas. However, Nose says that ice plant is completely different from mangrove.
“Ice plant loves salt, but mangrove does not. In other words, mangrove has no choice but to live near and in sea water. They have a special filter in their roots, making it possible to absorb pure water from sea water. But the absorbed water is not pure enough. It’s still salty. So, they have the other special system with their leaves, taking out salt in the absorbed water.”
Ice plant works
With the results of these studies, Professor Nose and Shimoda are preparing for the next step, culturing ice plant on the frontline of desertification, which is the salty land.
“Only ice plant can grow on such land, though nobody has ever tried such a project, yet,” says Nose. “In China, for instance, about 99 million hectares have turned into desert. Considering Japan’s total cultivated acreage is about 6.5 million hectares, you can easily understand that the scale of desertification there is enormous.”
The further progress of such desertification has had a negative impact on China’s food production. In addition, yellow sand is carried to Japan by the wind from deserts on the Chinese continent, causing various problems, such as killing trees, in Japan.
Professor Nose and Shimoda, saying that culturing ice plant could be an effective and realistic means to discourage the progress of desertification in China, has started a joint research project with a Chinese university of agriculture, focusing on desertification expanding from Mongolia to Shanghai.
Professor Nose is also studying another potential for ice plants: improving the plant as an edible vegetable for the Japanese market. The wild ice plant has been already developed and is edible in France. A limited amount of the plant is sold at high prices through on-line shopping services even in Japan.
With support from Japan’s Ministry of Agriculture (2004 and 2005) as well as Saga Prefecture (October 2006 to September 2008), Professor Nose and his project team are working on a new vegetable based on ice plant, organically cultured in water. They call it Barafu (means ice or crystal in Swahili).
“So far, we have two assignments. One is to control the salty taste of the plant. The other is to analyze the amounts of two key substances the plant contains--myo-inositol, which promotes fat metabolism, and pintol, which promotes development of low blood sugar levels, just like insulin.
In business relations with four farmers and 1 agriculture corporation in Saga Prefecture, the professor and the team have been working to produce Barafu.
It has been 24 years since Nose discovered ice plant in the desert near San Diego. Today, Nose’s instant curiosity is turning into the last resort for discouraging the progress of desertification in China as well as a new brand vegetable in Saga Prefecture.