AbstractsBiology & Animal Science

In all plants, including fungi and algae, as well as higher forms, this periodicity of growth, due to season, nutrition, environment, etc., is seen. Practically all temperate zone plants exhibit a yearly periodicity. The change in season causes a period of activity in summer and a corresponding one of rest in winter. Seeds also show this same phenomenon of periodicity of growth. The fact that nearly all plants exhibit a periodical rest period, during which - under normal conditions - there is no growth, has long been known, and the general problem of discovering the causes and factors influencing this dormant period has interested investigators for many years. However, it is only within the last few years that any definite knowledge has been secured in answer to some of the many interesting questions arising from a consideration of this fundamental plant-growth problem. Much work must still be done before the final explanation of some of the phenomena accompanying the dormant period can be satisfactorily made. The following report, dealing with an investigation of the rest period of seeds, is only one specific part of a problem dealing with the rest period of plants in general.