How Long Do Seeds Persist?

Press, Volume CI, Issue 29797, 13 April 1962, Page 7

How Long Do Seeds Persist?

A correspondent poses an interesting query in this week’s mail. She writes: “For the last 70 years at least, a shop and house have been on a certain piece of land. Now that these buildings have been demolished a big crop of weeds has come up. principally fat-hen. Where have the seeds come from?"

This is an excellent piece of evidence of the longevity of fat-hen seeds. There are previous records of fat-hen seeds surviving 50 years in the ground, but this case is even longer. The conditions would be excellent for a long life, however, for the cool, dry conditions existing under the building are those 'which are known to give maximum life in a seed. If the seeds had been in soil which was exposed to wetting and drying, and to considerable changes of temperature, there is no doubt that they would have died during this length of time. So the answer to the

query is simply that there were seeds m the soil all the time!

The longevity of these seeds is remarkable, but there are authenticated cases of even longer life with some plants. An experimenter from the Museum of Natural History in Parts attempted in 1934 to germinate seeds which had been in the muaeum's seed collection from the late 1700’s onward. The longest life obtained was from a Cassia, which germinated after 158 years!

An experiment started 4n 1879 by Dr. Beal, of Michigan State University, demonstrated that both dock and red shank are capable of remaining viable after 70 years' storage in mdut soil. The longest life of all, however, has been with one of the water lilies, seeds of which were recovered from a dried-up lake bed in Manchuria. The seeds, which were still capable of germinating when tlie seed coat was filed to allow the intake of water, were "dated" by the use of radio-isotopes as being somewhere between 830 and 1350 years of age! It looks as though the adage about “one year’s seeding ss seven years’ weeding" is a pretty hefty under-estimate!