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Rodents feeding on sweet mignonette love the fruit, but dislike the spicy seeds. So they spit them out, thereby dispersing them--to the plant's benefit. Karen Hopkin reports.

June 14, 2012

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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 assistants dont digest the very seeds theyre meant to spread.

In Israels Negev Desert, a plant called sweet mignonette came up with a 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. Thats according to a study in the journal Current Biology. [Michal Samuni-Blank et al, Intraspecific Directed Deterrence by the Mustard Oil Bomb in a Desert Plant]

Sweet mignonette produces little black berries that house about 20 seeds apiece. Inside those seeds is an enzyme. When a berry-chomping mouse crushes a seed, the enzyme is freed up to produce compounds that taste like hot mustard. Hence, ptooey, better leaving through chemistry.

Excerpt from:
Plant's Chemistry Gets Mice To Spit Seeds