230 



Physiological Pre-detennination 



With regard to the growth of the normal plant the general law was 

 formulated to the effect that during the vegetative growth period the 

 dry weight of the plant increases according to the jjrinciple of a geometric 

 series^. This law amounts to a statement that the total dry weight of 

 the plant increases on a "compound interest"' basis. From this law it 

 follows that there are two main factors which control the final vield: 



160 



Fig. 1. Total dry-weight increase in the case of a, normal plants of Helianthus annuxis 

 Bismarckianus; b, plants from which one cotyledon and one foliage leaf had been 

 removed; c, plants from which both cotyledons had been removed. (After Gcricke.) 



^ The results of a series of investigations, wiiich were carried out in CU'niuiny on the 

 suggestion of the Ministry of Agriculture, and which were recorded in the Laudwirth- 

 achaftliche Jahrbiicher, 1877-79, supply a mass of detailed data with regard to the normal 

 growth, the increase in dry-weight, and the change in leaf-area of a number of cultivated 

 l)lants. These data appear to support the general law formulated above. 



