What grows in salt water? That was the question facing Wenhao Sun as he researched phytoremediation — the use of plants to treat environmental problems; in this case, to clean polluted water.

Sun was principal investigator for Marine Agritech in the effort to use native Hawaiian 'akulikuli to rescue the filthy Ala Wai Canal by means of bacteria and micro-organisms that colonize the roots and improve water quality through their nutrient uptake.

Building on that venture, which is showing signs of success, Sun and his partners in Marine Agrifuture, a spinoff of Marine Agritech, began a search for other salt-tolerant plants. But this time, the point was to raise food plants, adding a new arm to the aquaculture industry in the Islands, where seafood and ogo already are being successfully farmed. 'Akulikuli is edible, but nobody seemed to like the flavor much.

Sun found a prime candidate in a plant with the family name Salicornia, a sea vegetable prized by cooks in the Mediterranean, a key part of the diet of Pacific Northwest Indian tribes and — this was important because of concern about introducing invasive species — once resident in the Hawaiian Islands. Sea asparagus beds in the Islands were wiped out during a 1989 storm, Sun said.

In the Pacific Northwest, where it's collected seasonally from the wild, chefs of fine-dining restaurants have pounced on the ingredient, with its crisp texture and pleasing flavor.

In Mexico and the Middle East, the plants are raised on dry land that is flooded with pumped-in seawater at regular intervals. But these plants are raised for seed, from which an oil high in healthful linoleic (omega-6) acid is pressed.

Working in a single greenhouse at the University of Hawai'i, Sun found that this versatile plant he calls sea asparagus could be successfully grown in a 50-percent mix of salt and fresh water enriched with organic waste. The seedlings are tucked into slotted plastic tubes set in plastic rafts, rooty toes in the water, fern-like green tops in the sun, ready for harvest in three months. A bonus: The plants happily share their ponds with fish or shrimp.

Sun learned that sea asparagus is almost ridiculously healthful. Besides being fat-free and rich in fiber, vitamin A and minerals such as calcium, magnesium, potassium, copper and manganese, plus vitamin B2 (riboflavin) and iodine, sea asparagus and other salt-tolerant plants contain trimethoglycine compounds that can help detoxify the liver, improve muscle function, reduce fat, prevent breakdown of DNA (associated with aging) and improve energy level, Sun said. Its sodium content is a concern to some, but Sun has developed a less-salty version, with 920 milligrams per 75 grams (2.6 ounces).

Reach Wanda A. Adams at wadams@honoluluadvertiser.com.