[Chap. XXXIV GROWTH, DORMANCY, GERMINATION OF SEEDS 397 



the effectiveness of low oxygen and low temperature storage conditions 

 on the retention of viability. 



Table 14. Percentage Germination of Air-dried Seeds of Delphinium Stored 

 in Sealed and Open Containers at About 70° F. and 46° F. (Data from L. V. 

 Barton. ) 



Storage 11 mos. 22 mos. 3 vrs. 10 mos. 5 vrs. 9 mos. 9 yrs. 3 mos. 



Condition 



The longest known period of survival of any seed is that of the lotus. 

 Seeds germinated after being kept in dry storage at the British Museum 

 for 150 years, but seeds from the same lot tested after 215 years failed 

 to grow. Seeds of this same species, Neltimbo nucifera, were viable after 

 burial in an ancient lake bed for at least 160 years, and probably for 

 more than 250 years, before their discovery in a road cut in Manchuria. 

 The hard seeds of the legumes are well known for their longevity; there 

 is a record of 158 years for a species of Cassia. Most agricultural seeds 

 live for 10 or 20 years, but the hard seeds of many crop legumes are 

 viable after 40 to 60 years. It should be noted, however, that the per- 

 centage of germination at the end of the longer periods is usually very 

 low. A number of seeds of wild plants with hard coats have records of 

 longevity up to 90 years. 



We still lack authentic records of the longevity of seeds stored in 

 hermetically sealed containers. The longest records are those derived 

 from "hard seeds" which represent seeds with embryos sealed indi- 

 vidually. Putting seeds in sealed containers is merely duplicating the con- 

 ditions within hard seed coats, for it likewise results in excluding oxygen 

 and water from embryos. 



A diagrammatic record of the famous experiments by Beal at the 

 Michigan Agricultural College is given in Fig. 174. Beal buried the seeds 

 in the soil in inverted open bottles in 1879. Bottles containing the seed 

 mixture have been dug up at five-year intervals and the number of living 

 seeds tested, with the results shown in the diagram. 



Why do dormant seeds die? This question has been asked for many 

 years and many answers have been proposed, but none of them has been 



