Pharoah`s ears

You can blame it on Napoleon. When he invaded Egypt in 1798, he took along 175 scholars. Although Napoleon`s army failed to conquer Egypt, his troop of intellectuals were triumphant. They "discovered" ancient Egypt and so triggered a craze that swept the whole of Europe. Fashionable society was soon in the grip of mummy fever. By the 1840s, the English papers carried regular reports of the amazing regenerative powers of "mummy wheat"-grain discovered in from tombs up to 6000 years old.

Some of these ancient seeds produced bumper yields from fat heads with as many as seven ears. In 1846, The Agricultural Gazette reported the excitement among members of the Newcastle Farmers` Club when they were shown an ear of wheat grown from a seed found in an Egyptian mummy case. "It is much more bulky than an English ear, being, in fact, seven English ears rolled into one!" This ear was more than a miracle of resurrection, pronounced the Gazette, it was evidence that the biblical story of Pharaoh`s dream was true. "And Pharaoh slept and dreamed the second time, and behold seven ears of corn came up upon one stalk..."

Each claim of success in raising mummy wheat brought a swift counterblast from botanists. Close examination of the seeds showed that although the outside looked intact, the embryo within was too badly damaged to germinate. Every attempt to grow authentic mummy seed failed. The sceptics argued that if anyone succeeded, then the grain they planted wasn`t as old as they had been led to believe.

In one famous instance in 1840, Martin Tupper, a popular writer of the day, claimed to have raised plants from mummy wheat. His seed came from an impeccable source-none other than Sir John Gardner Wilkinson, the most eminent of English Egyptologists. Later, it turned out that Tupper`s own gardener had scattered modern seed among the ancient to ward off disappointment.

There were other reasons why mummy wheat might be more modern than any mummy. For centuries, ancient tombs had been used to store grain. Mummies were often shipped to Europe packed in straw, with seed heads still attached. And Egyptian guides quickly realised that gullible tourists would pay well for grain, and kept handy supplies hidden in the tombs.

But it was the plants themselves that provided the best case against mummy wheat. The ancient Egyptians grew two main cereal crops, emmer wheat and barley. Obviously something was wrong if the seeds grew into oats or maize-species not present in ancient Egypt. When the plants did turn out to be wheat, it was usually a modern variety of bread wheat. And when the wheat was the seven-eared sort that Pharaoh dreamed of, it was invariably rivet wheat, unknown in Egypt at the time.

Despite all the evidence, the story still wouldn`t die, much to the annoyance of Wallis Budge, keeper of Egyptian antiquities at the British Museum. For years, he received two or three letters a week asking if it was possible for mummy seeds to grow. No, he replied, it was not. In 1897, in an effort to dispel all doubt, he bought a model granary, which had been excavated from a tomb at Thebes. The grain inside was 3000 years old. Budge gave some of the wheat to the director of Kew, who planted it under the watchful eyes of almost the entire staff. "They waited day after day, week after week, but no shoot of any kind appeared," Budge wrote in a letter to The Times. "At length after three months, they turned over the little plots and found that all the grains had turned to dust."

In 1933, the press reported a new case of wheat that had sprouted from ancient seeds: this time the grain came from a 4000-year-old tomb in India. Would Budge now admit there might be something to this mummy wheat? "No competent botanist believes that ancient Egyptian wheat will germinate," he declared in The Times. But lest anyone doubt it, he still had some seed left and would donate some to any reputable grower willing to test it.

The National Institute of Agricultural Botany took up the challenge, and reported its findings back to The Times. "After the fourth day, the grains had become slimy. At the end of 16 days in test, not only had every grain completely decayed, but a thick growth of mould had spread from them to the surrounding sand."

So why do many people, including archaeologists, still believe that these ancient seeds will grow? This is a question Mark Nesbitt, an archaeobotanist at Kew, has been pondering for some time. He suspects thatalthough earlier botanists debunked the idea fairly convincingly, they never provided a proper explanation for why a seed couldn`t survive thousands of years if it was kept in the arid interior of a tomb.

Over the past few decades, scientists working in seed banks have discovered much about the ageing process inside a seed, and the conditions that will prolong its life. Most cereals can be stored for centuries if they are partially dried and kept at subzero temperatures and low humidity, although exactly how long depends on the species. With the help of artificial ageing experiments, seed-bank scientists have produced sophisticated models that predict the shelf life of a seed under given conditions.

At Kew`s Millennium Seed Bank, John Dickie has now modelled the lifespan of mummy wheat. Cereals all behave much the same in storage, so Dickie assumed mummy wheat would deteriorate at a similar rate to modern varieties. Feeding this data into the model, he then added information about conditions in an ancient tomb.

One of the best-studied rock tombs is that of Nefertari, the favourite wife of Ramses II, who lived in the second millennium BC. The relative humidity in the tomb is a low 16 per cent-ideal for seed storage. But even deep inside the rock the temperature fluctuates widely, ranging from a low 16 �C to 28'�5 �C-bad news for seed survival.

Dickie found that if he started with top-quality seed and the temperature remained constant at 16 �C, one grain in a thousand might still germinate after 236 years. With the temperature sometimes hitting the high 20s, the grain would all be dead in 89 years. And if the seed was less than perfect to begin with . .

Author: Stephanie Pain, New Scientist Associate Editor

New Scientist

RSS Feeds

Pharoah`s ears

Science Research Departments