Science: Weedy Legacy

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Germination after generations

In 1879 the famed botanist William Seal, a pioneer in the development of high-yield corn hybrids, began a bizarre experiment. He buried 20 pint-size bottles, each containing 1,000 seeds of 20 weed varieties, near his lab in East Lansing, Mich. His aim, in that age before weedkillers: to find out how long plowed-under seeds could survive, and thus, how long fields needed to be left fallow, to ensure a weed-free crop when replanted.

A very long time, it appears. After five years Beal unearthed one of his botties and, lo, the seeds sprouted. He kept at the experiment, exhuming a bottle every five years, and found each time that samples of all varieties would germinate. In 1920 Beal changed the digging schedule to every ten years. At his death in 1924, at 91, the experiment was inherited by colleagues at Michigan State College (now University), who had been bequeathed a map showing where the remaining bottles were buried. By 1960 only three varieties of seed still grew. A decade later, one hardy weed survived: Verbascum blattaria or moth mullein.

The seeds in the bottle unearthed this year were planted, as usual, in soil sterilized by steam. But at first nothing happened. Had the century-old seeds finally expired? No. After several weeks the first seedling emerged; within five months 29 seeds had germinated. Six of the seedlings died. Of the survivors, 21 are moth mullein, one is another type of Verbascum and the last a variety of the Malva species that had not sprouted since 1899.

Under the direction of Biochemist Robert Bandurski, M.S.U. botanists will try to germinate the remaining 1980 seeds One method they will use is vernalization, in which the transition from winter to spring is re-created by refrigerating the seeds briefly before exposing them again to warmth and light. The seedlings will be nurtured until they produce seeds of their own, in the hope that the progeny will offer clues about the mutating effects of 100 years' exposure to the natural radiation in the soil. Enough bottles remain buried to carry on Beal's experiment until 2040. More time might help; by some accounts, seeds from the tombs of the pharaohs have sprouted thousands of years after they were buried.