— 247 — 



will be on the whole proportional to the dry matter of the plant. 

 By and by, when a part of the new built matter is used more for 

 the formation of stem and root, that consumes matter instead of 

 producing it the dry matter of the plant will increase more slowly. 

 As a fact, the shape of the curve from June 6 to July 20 is almost 

 rectilinear. In the first part of August the leaves are lost. Hence 

 the production of matter will cease and, as may be seen from the 

 curve, the dry matter content of the plant will diminish, partly 



May June July August 



Fig. 6. The content of dry matter in the different phases of development 

 in Sinapis alba (Hornberger). 



because of the loss of the leaves and partly because the respiration 

 of the stem, root and seeds goes on for some time. 



5. Production of matter per unit of area. Finally I will 

 give some figures for the production of dry matter in Sinapis per 

 hectare, taken from Hornberger's paper. The seeds were sowed 

 on April 24, 7 kg per ha, and the experiment lasted until Aug. 18. 

 In this time the production of dry matter per hectare in kg was 

 as follows: (The figures indicate the greatest values, not always 

 the value at the termination of the experiment). 



Leaves 857 kg 



Stems 5856 - 



Shells 2255 - 



Roots 311 - 



9279 kg 



