THE ONE HUNDRED-YEAR PERIOD FOR DR. BEAL'S SEED VIABILITY EXPERIMENT

After 100 years of burial in moist well aerated sand, 21 seeds of Verbascum blattaria, one seed of Verbascum thapsus and one seed of Malva rotundifolia, germinated and produced normal plants. Six additional seeds, of the original 50 seeds of each of 20 varieties, germinated and died before identification was possible. THE SPRING OF 1980 marked the 100-year period for the seed viability experiment initiated by Dr. W. J. Beal, then professor of botany and forestry at the Michigan Agricultural College in East Lansing. The experiment is best described by Dr. Beal (1905): "In the autumn of 1879, 1 began the following experiments, with the view of learning something more in regard to the length of time the seeds of some of our most common plants would remain dormant in the soil and yet germinate when exposed to favorable conditions. I selected fifty freshly grown seeds from each of twenty-three different kinds of plants. Twenty such lots were prepared with the view of testing them at different times in the future. Each lot or set of seeds was well mixed in moderately moist sand, just as it was taken from three feet below the surface, where the land had never been plowed. The seeds of each set were well mixed with the sand and placed in a pint bottle, the bottle being filled and left uncorked, and placed with the mouth slanting downward so that water could not accumulate about the seeds. These bottles were buried on a sandy knoll in a row running east and west." During the first 35 yr of the experiment, germination tests were performed every 5th yr, and every 10th yr thereafter (Beal, 1884, 1885, 1889, 1894, 1904, 1905, 1911; Darlington, 1922, 1931, 1941, 1951; Darlington and Steinbauer, 1961; Kivilaan and Bandurski, 1973). The 14th I Received for publication 8 July 1981. This work was supported, in part, by the NSF grant PCM 04637 and is journal article no. 9965 from the Michigan Agricultural Experiment Station. The authors and Dr. E. J. Klos, Mr. E. Light, Ms. A. Schulze, Mr. S. Zeevaart and Dr. J. Zeevaart were present at the exhumation and Mr. E. Light, C. Kalomeris and L. Kemme helped in the care of the plants using greenhouse facilities supplied by Michigan State University-Department of Energy (DEAC02-76ERO1338). bottle was recovered for testing on April 16, 1980, leaving six more bottles for future tests. Germination tests with the Beal seeds-Germination tests were performed in a greenhouse during the summer months of 1980. Our germination tests included only the 20 species of seed included in the bottles by Beal and excluded the three species ( Quercus rubra, Thuja occidentalis and Triticum sp.) he had buried alongside the bottles. A soil mixture, consisting of approximately equal parts of well-sifted loam, sand and muck soil, was steam-sterilized for three 12-hr periods under 10-12 lb pressure. Three clean plastic trays, with perforated bottoms for drainage, were filled with the soil mixture. The surface of the soil in one tray was spread evenly with the contents of the unearthed bottle. This is essentially the procedure used previously (Darlington and Steinbauer, 1961). A second tray was planted, for identification purposes, with freshly harvested seed of species which had been found to be viable during prior, recent tests (Oenothera biennis L., Rumex crispus L., and Verbascum blattaria L.). The third tray was kept unplanted as a control for the absence of viable seeds in the heated soil substratum. Trays were placed in an air-conditioned greenhouse with a minimum night temperature of 22 C and ambient day temperatures. The natural daylength was supplemented with light from fluorescent tubes to attain a photoperiod of 20 hr. Watering was done as frequently as required to keep a moist soil surface. The tray containing the 100-year-old seed produced altogether 29 seedlings during a 14wk period. Since no additional plants emerged in a subsequent 2-wk period, the tray was left unwatered for 3 wk, and, following that, the soil surface was slightly disturbed and watering resumed for a 3-wk period. No new seedlings emerged. A 2-wk-long treatment of the moist