SSS 2012-06-14（在线收听）

 Plants that use animals to disperse their seeds can find themselves in a pickle: They need to make fruit tasty enough to entice the local fauna, but they also need to make sure that their animal asssistants don't digest the very seeds that are meant to spread. In Israel's Negev dessert, a plant called seed mignonette came up with the distasteful strategy. Critters called spiny mice feed on mignonette. They love the fruit, but they hate the seeds. And so they spit them out all over the place---just as the plant planned. That's according to a study in the journal Current Biology. Sweet mignonette produces little blackberries that house about tweenty seeds apiece. Inside those seeds is an enzyme. When a berry-champing mouse crushes a seed, the enzyme is freed up to produce compounds that taste like hot mustard. Hence,..., better leaving through chemistry. Researchers armed with video cameras observed the mice spitting the pits like kids eating watermelon on a summer day. Nearly three quaters of the spit-soaked seeds landed intact. And they actually germinated twice as fast as seeds taken directly from the fruit itself. It's like a Dickens book: Great Expectorations.