Gregory A. Koob, research assistant at Lyon Arboretum, and his staff - mostly volunteers - have been micropropagating 81 of Hawaii's endangered plants. Koob has had failures along with successes, but 51 of his test tube plants look promising.
The propagation process is based on the fact that a single cell from bud or leaf tissue can regenerate an entire new plant, which will be a duplicate or clone of the parent. Tissue is collected from the plant and placed in a jellied solution in a sterile test tube. The solution contains all the nutrients the plant will need, and the formula differs with each species.
Careful records are kept on each test tube, and when its tenant is big and strong enough, it is moved to a larger tub. Later the plant is transplanted and moved to the greenhouse and if all goes well, it is returned to the wild.
Through this process, Koob is doing more propagation on federally endangered plants than any other laboratory in the country.
Koob's laboratory is in the living room and kitchen of what was a caretaker's cottage on the arboretum driveway. It is now furnished with thousands of small glass test tubes, each housing a young plant.
Not all of these plants are endangered. The laboratory got its start on a more commercial level, and it now has two goals. "We are propagating endangered species of Hawaiian plants, and we are also propagating exotic (nonnative) plants for arboretum use." The latter, Koob added, are for plant sales and eventually will be made available to commercial nurseries and landscapers.
"By keeping everything clean, the plants are kept free of bacteria and fungi," Koob said. "We prefer to propagate from seeds when we can, rather than from tissue culture, because they give us a wider genetic pool. Tissue from buds or leaf cuttings provide a copy of only that plant.
"The plant population from tissue culture is not as viable. It loses its ability to produce seeds, and sometimes can't adapt to environmental change." Seeds grown in the sterile environment of Koob's lab stand a better chance of surviving than those planted in the arboretum greenhouse because they aren't attacked by bugs and viruses.
And there's another benefit. "In the greenhouse, you get one plant from one seed, but here we can grow as many plants as we want by micropropagating the seedling. We can use those copies in the restoration of the plant population. If the first one dies, we still have many copies."
Koob's greatest success to date is with Cyanea pinnatifida. "There was only one plant existing in the wild, at The Nature Conservancy's land in the Waianae Mountains," Koob said. A member of the lobelia family, it once grew as a bush or small tree in the Hawaiian native forests.
"The single plant hasn't flowered in the wild for more than 30 years, so there are no seeds. We took bud tissue to make copies, so that if anything happens to that plant we have duplicates.
"The Nature Conservancy put several plants back on their land, and we put one in our greenhouse. That one flowered, so now we have seeds, and we have made seedlings. When they mature and flower, we will cross pollinate the plants to mix up the genes, and we hope to get some variability. It will take a long time, but we are on our way."
But there have also been setbacks . Kokia cookei, a member of the hibiscus family, has been grown from plants raised at Waimea Falls Arboretum. They set seeds, but the mature seeds die without germinating. "If you slice the seed open, you find that it is empty.
"But when the seeds are immature, the embryo is still OK. So we took immature embryos and grew them into seedlings and then sent them to our greenhouse. They died, and we have never been able to create more."
Koob and his crew are also propagating Polynesian introductions brought here by the early settlers. These include 67 forms of taro. "The Hawaiians actually brought in two varieties and created more than 70 others. They were such good farmers that they recognized the smallest changes in their plants," Koob said.
These early farmers removed the keiki from the mother plant, cultivated it, and named it if it were something they wanted to keep. "These are fairly easy to micropropagate," he said. "Many of them will be available at the arboretum's March sale."
Koob is also cultivating Hawaiian tree ferns and other nonendangered native plants with the goal of making them available to growers. "Why grow monkeypod when you could have ohia or koa?" he asks. "These plants are adapted to Hawaii, and when you plant a dry land plant in a dry area or a wet land plant in a wet area, it will need far less maintenance than an introduction."
Koob, who has his doctorate in horticulture from the University of Hawaii, explains that micropropagation alone is not going to get Hawaii out of first place on the plant extinction list. Successful plant propagation in the wild is dependent upon birds and insects, upon shade from the forest above and mulch from the understory of groundcover. It's an ecosystem, one dependent upon the other. But Koob and the arboretum have taken a giant step in the right direction.
