Ever green

日期:2017-10-15 01:28:13 作者:麻樯章 阅读:

By Jeff Hecht 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,