CHE REFERENCE LIBRARY - ZetaTalk

If seeds are buried in the grouncl and exposed to the actionof frost, the period of dornianr*y is usually com&%ddy redWd. Thus Pam mr4 nntl King ribport ( I’IYW. Iowa Acad.Sci. xl-) cxpcrinWnt s by I1’awcett showing that “ the dormantperiod of common pigweed (A Iuwfwtu~s ~Yrf$le.r0s) wa3 nine andone-third da>-s when kept in pa,ckages in a dry room, a,nd onlysix and one-t.hird days after having been wintered out of doors.In the case of wild rye, the dormant. period was lessened fromnine to five days . . . while the percentage of germinationwas increased from 22 per cent to 48 per cent,, and, the pigweedfrom 40 per rent to 50 per cent. In geneA, the longest dormantperiod was found in those seeds which have the hardestand thickest. coats.‘?The better germination of some kinds of seeds after beingsubjected to freezing is t.he result of the cracking of the shelland the letting in of moisture, rat,her than the lessening of aninherent dormancy ; perhaps this is always the explanation.Plant-growers resort extensively to the burying of nuts andhard-shelled seeds to insure germination. They also file ornotch certain seeds, as those of the moonflowers, to allow waterto enter and to start the germina,tion processes, taking care, ofcourse, not to injure the embryo.How long germination may be delayed and the seeds stillremain Gable (or germinable) depends on the kind of plantmore than on the conditions of storage. The longevity ofseeds, in other words, is largely an hereditary trait lying probablyin the anatomy and cl1emica.l constitution, In this realm,new experiments are needed on a considerable scale, reinforcedby the modern understanding of the physiological processes.The stories of live seeds being taken from the mummies ofancient Egypt are not credible ; these statements have oftenbeen exposed. Yet certain seeds may outlive a human life.I’ammel and King report the following table from Ewart, ofVictoria (Australia), on certain rather remarkable longevities :