Seeds of a 142-year-old science experiment germinate
Last Thursday morning, several hours before sunrise, Marjorie Weber arrived at a rendezvous spot on the campus of Michigan State University. Three of the school’s other plant scientists were already there, waiting in dribbling snow. As they stood around blowing on their hands, the fifth member of their crew, Frank Telewski, “emerged from the darkness with a shovel slung over his shoulder,” Weber said. With everyone else crowded around, Telewski, the group’s leader, pulled out a copy of a map, drawn like an architectural blueprint. It would guide them to a botanist’s version of buried treasure: a bottle filled with sand and a bunch of really old seeds.
Weber and her colleagues are the latest custodians of the Beal seed viability experiment: a multi-century attempt to figure out how long seeds can lie dormant in the soil without losing their ability to germinate. Every 20 years, the experiment’s caretakers creep out to a secret location under cover of night, dig up a bottle, scatter its seeds over a tray of sterile soil and see which ones grow.
It is one of the world’s longest-running experiments, having already gone on for 142 years. And the botanists in East Lansing hope that it will last for at least another 80. What started out as a straightforward attempt to measure seed persistence has grown into a more interesting experiment as the decades pass. With technology improving and knowledge increasing, the keepers of the cache can do more than just count each bottle’s successful sprouts.
They can look inside seeds to see how they tick, begin to determine what accounts for longevity — and even, in some cases, get species that seemed done for to spring up again. Lessons from their work could help with everything from restoring damaged ecosystems to storing crop seeds for the long term. But first, they had to find where to dig. The bottle the team was looking for contains more than 1,000 seeds: 50 each of 21 different species, from black mustard to white clover to redroot amaranth. In 1879, William James Beal, a botanist at Michigan State, filled 20 such bottles and buried them in a row somewhere on campus. He figured he — and later, his successors — could dig one up every five years and plant the preserved seeds inside. When seeds are shed by their parents, they do not always grow right away. Under any given patch of land, there is a constellation of sleeping seeds “biding their time,” Weber said. Often, they lie dormant — for a season, a few years or even longer — until they get the right set of cues to sprout. Today, farmers do not really need the kind of help with weeds that motivated Beal to bury his bottles. But plant scientists have become invested in the question of which seeds last and how for other reasons. In some cases, seeds of endangered or long-lost plants may even be hiding out in the soil. To avoid losing the thread across these decades, a sort of ministry of seed-keepers has developed at Michigan State, with each generation of botanists passing the torch to younger colleagues.
Planting a seed is like asking it a yes or no question; the seed either sprouts, or it does not. But often a seed that does not grow is not fully dead. Examining its DNA and RNA lets scientists interrogate it much further; they can find out whether its machinery has degraded or persisted, how damaged the genetic material is, and what processes may still be possible even if germination is not, said Margaret Fleming, a post-doctoral researcher.