A NOVEL way of treating seeds with natural plant growth hormones could help
restore Florida’s Everglades to their former glory.
The cornerstone of this fragile ecosystem is a sedge called sawgrass,
Cladium jamaicense, which once covered up to 80 per cent of the Everglades.
Sawgrass normally spreads by rhizomes, and withstands both drought and flood.
But excess nutrients from agricultural fertilisers and disturbance by boats have
destroyed large areas of sawgrass. Because its seeds germinate poorly,
faster-sprouting cattails, Typha dominicans, then take its place.
This threatens the entire ecosystem, says Charles Carraher of Florida
Atlantic University in Boca Raton. Not only do cattails struggle to deal with
extreme high or low water levels, but their roots also fail to support the layer
of microscopic life called paraphytin that is the base of the Everglades food
chain.
Spreading seeds from boats or planes would be the easiest way to regenerate
sawgrass, says Carraher, if enough seeds could be made to sprout. To increase
the germination rate, he synthesised polymers consisting of chains of giberellin
or kinetin growth hormone molecules, then mixed them with talcum powder to make
them stick to the seeds. “Over time, the polymer degrades and gives up the plant
growth hormone,” Carraher says. Adding tin to the polymers prevents fungal
infections for up to three months.
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The treatment can raise sawgrass seed germination rates up to 25-fold.
Carraher hopes to begin trials in the Everglades within the next year or
two.
