By KAREN BINDER
Illinois Correspondent

CARBONDALE, Ill. — For those in the business of growing plants, a Southern Illinois University Carbondale researcher believes “cookies” may be the way to go.

While plant growers have been using manmade “seeds” to produce new shrubs for several decades, doctoral student Laurie J. George has developed a cookie that yields five times as many plants, as compared to artificial seeds. The College of Agricultural Sciences student uses a mixture of processed kelp, tissue culture media and calcium chloride, making the cookie chemically similar to natural seed coverings.

As she varies the concentrations of the cookie mix and adjusts the time spent sterilizing it, George can increase the number of plant starts from one to five. Seven weeks later – after four weeks of refrigeration and three weeks of light – they are ready to grow.

George believes the technique is more prolific, and less costly, than using artificial seeds.

“The artificial seeds encapsulate individual nodes, which takes a lot of time and labor,” she said. “While there are machines that do encapsulation, they’re costly, and they have a lot of moving parts which require maintenance.
“What I am trying to do is reduce these costs by focusing on mass encapsulation. It’s a technique smaller operations could use without a high cash outlay, and it can increase the numbers of plants that might not produce viable seeds on their own, plants that are rare and plants where we need to preserve their germplasm.”

She has been working with a cultivar of Hibiscus moscheutos called Lord Baltimore. The hardy perennial, sometimes called a swamp mallow because it likes bogs and marshes, can grow 5-6 feet tall each season and bears dramatic red flowers the size of a dinner plate.

Despite some early challenges – everything from what George refers to as a “high learning curve” in tissue culture (the process by which she gets the stock plants that supply the nodes she needs) to power and refrigerator failures, to thrips in the lab – George has mastered the art of the cookie, at least as far as Lord Baltimore is concerned.

“We have it pretty much down pat in getting plants started, and I am having really good luck in getting them established and growing them out,” she said.
“I’m focusing now on improving the survival rate after cold storage. Currently, between 70 and 75 percent survive, so the majority is re-growing and being reproduced as plants we can sell. But you want to have 100 percent survival rates.”

George also is attempting mass encapsulation with Snow Queen, a cultivar of the native Hydrangea quercifolia, a shrub prized for its showy look and exfoliating bark. This is proving trickier.

“It’s been a learning process for the hydrangea because it’s a totally different process from the hibiscus,” George said. “The cookie matrix had to be different, the sterilization process had to be different. Hydrangeas also are slow growers in tissue culture. Instead of a month or month-and-a-half to get plant material, I’m having to wait two to three months.”

George is seeking answers to some big-picture questions: Will mass encapsulation protect the nodes better than individual encapsulation does? Will it allow them to remain in cold storage for longer time periods – say, a year or longer? And will they re-grow as well or better than individual nodes once cold storage ends?

“I am hoping that because I have more material around the roots, I will have a better survival rate,” she said.