Seven date palm trees have been grown from 2000-year-old seeds that were found in the Judean desert near Jerusalem.
The seeds – the oldest ever germinated – were among hundreds discovered in caves and in an ancient palace built by King Herod the Great in the 1st century BC.
Sarah Sallon at the Louis L Borick Natural Medicine Research Center in Jerusalem and her colleagues previously grew a single date palm tree (Phoenix dactylifera) from one of the seeds. The team has now managed to grow a further six.
The ancient seeds were prepared by soaking them in water, adding hormones that encourage germination and rooting, then planting them in soil in a quarantined area.
The team used radiocarbon dating to reveal the seven seeds were all around 2000 years old. Genetic analysis showed that several of them came from female date palms that were pollinated by male palms from different areas. This hints that the ancient Judean people who lived in the area at the time and cultivated the trees used sophisticated plant breeding techniques.
Sweet and juicy
Historical accounts of the dates that grew from the palms in this region describe their large size, sweetness and medicinal properties. The Roman scribe Pliny the Elder, for example, wrote that their “outstanding property is the unctuous juice which they exude and an extremely sweet sort of wine-flavour like that of honey”. Unlike Egyptian dates, they could be stored for a long time, meaning they could be exported throughout the Roman Empire.
Sallon and her colleagues found that the seeds of ancient Judean dates are larger than modern varieties, which is often indicative of bigger fruit. They now hope to recreate the ancient fruit by pollinating females with males.
Judea’s date palm crops started to die out after the region’s wars with Rome in the 1st and 2nd centuries AD. Sallon believes the hot, dry conditions of the Judean desert probably helped to preserve the leftover seeds for so long.
Previously, the world’s oldest germinated seed was a 1300-year-old Chinese lotus seed recovered from a dried lake bed in China. In 2012, researchers in Russia grew a flower from 30,000-year-old fruit tissue recovered from frozen sediment in Siberia.
Journal reference: Science Advances, DOI: 10.1126/sciadv.aax0384