2 Physiological Prc-determinatiou 



cent., or even more, owing to the pre-determining influence upon the 

 resultant plant of the physiological condition of the seed as effected by 

 environmental conditions both previous to and also during germination. 



The plant physiological problem which we are raising and with which 

 we propose to deal in this and in following papers under the same general 

 title, may be stated formally at the outset as follows : Presuming always 

 a given equal number of plants, what are the limits of variation in growth 

 and yield which may be pre-determined by the action of environmental 

 conditions during the seed stage both previous to and during the course 

 of germination ; and how far may later environmental conditions during 

 the course of growth affect the latitude of such variation? 



The experimental work conducted by the authors dealing with the 

 problem thus outlined is in progress. The present paper deals with the 

 first results of experiments designed to test the effect of preliminary 

 soaking of the seed upon its subsequent growth and development^. 



In the next paper of this series the literature bearing directly or 

 indirectly upon the subject will be reviewed. This review will clearly 

 indicate the wideness of the field and the possibility of obtaining impor- 

 tant results if experimental work on a sufficiently large scale be carried 

 out both in the field and in the laboratory. 



The stage of germination is obviously a very critical one in the life- 

 history of the plant. By artificial control of the environmental con- 

 ditions of the seed previous to and during the process of germination 

 the cultivator may aim not only at the natural optimum, that is the 

 yield produced by good seed under the most favourable conditions, but 

 may even improve upon this. 



EXPERIMENTAL. 



Experiment 1. Seeds soivn on damp sand. 



Seeds of the following plants were used in this experiment, viz. 

 culinary pea {Pisum sativum), dwarf bean {Phasenlus vulgaris), barley 

 (Hordeum), and sunflower [Helianlhus annuus). The seeds were soaked 

 under 4 cm. of distilled water at an average temperature of 17° C. (i.e. 

 the temperature of the laboratory) for periods varying from 8 to 72 hours 

 and the result of this treatment upon the germination (Table I) and 

 upon the subsequent growth of the same seeds (Table II) was observed. 

 In this experiment both germination and growth occurred with the seed 

 lying on damp sand in porous pots surrounded with water and loosely 

 covered with glass. 



^ The experimcnta described in thia paper were catriod out during thi.' autuiun nf I'.HT. 



