236 



Physiological Pre- determination 



(d) At a later stage the experimental plants take the lead, and 

 flower before the control plants. 



(e) The experimental plants have a longer growth-period and 

 flowering-period than the control plants, arrive at maturity at a later 

 date and give larger final yields, and this probably accounts for the fact 

 that plants from seeds which are soaked in water previous to sowing 

 are more productive than plants from untreated seeds. 



(/) Soaking the seed in a relatively large volume of water, for 

 instance, ten volumes of water to one volume of seed, reduces the 

 beneficial effect, and may even be harmful. 



(g) The soaking treatment is especially useful when the seeds are 

 sown in light dry soil, provided that the seed is well covered with the soil. 



In view of the importance of their results we may give in full an 

 account of a few typical experiments carried out by Kraus(25) and by 

 Wollny (42). Kraus carefully analysed at all stages of development of the 

 plants the effect of the seed treatment. The following is a summary 

 of the results of three of his experiments carried out with beans, peas, 

 and seeds of Lujnnus angustifolium respectively. 



Experimental data. 



Soil. Deep loamy sand (Keuper). 



PrevioHS Historij. Crop maize, stable manure applied. 



Preparalion of the Soil. In the spring the ground was dug deeply with a spade. 



Cultivation of the Ground. Weeded and hoed. 



Date of Sowing. April 20th. 



Weather Conditions during Experiment: 



Kind of Seed used. Carefully selected large seeds. 

 Treatment of the Seed: 



1. Untreated (= controls); 



2. Swollen in water for 24 hours, afterwards quickly dried; 



3. Swollen in water for 24 hours, sown in the moist condition. 

 (During tlie soalving-treatment a few of tlie peas had sprouted.) 



Spacing and Depth of Solving: 



Number of seeds 



Spacing Depth in each row 



Beans 15 em. 4 em. 42 



Peas 10 em. ."{ cm. 42 



Lupins 15 cm. 3 cm. 30 

 Harvested. August 3Gth. 



