2IO 



U. SUZUKI. 



in the latter. The reserve nitrogen is therefore hardly sufficient 

 for the normal development of the shoots, and some plants may 

 suffer in consequence and become diseased. 



One may ask now, how can we explain the fact that some 

 varieties, like Takasukc, become diseased more easily than 

 others, like Jumonji. This 1 shall explain fully in the following 

 pages. 



As we see from the results of the analyses, the decrease of 

 nitrogen in the bark of the roots of Jumonji during the growing 

 period, is smaller than in Takasuke and Tsuruta, 

 and the total quantity of reserve nitrogen is also far smaller in 

 Jumonji than in the other two. This means that Jumonji needs 

 a far smaller quantity of reserve nitrogen to build up the same 

 quantity of leaves and new shoots. The roots of Jumonji seem to 

 be especially fitted for the absorption of soil nutriments, and to 

 make good the deficiency of the reserve materials already pre- 

 sent. If now we compare the nitrogen contents of the leaves in 

 the three varieties we find : 



Takasuke. Tsuruta. I union ji. 



April 28, 6.40 6.80 576 



May 18, 5.00 4.30 4.00 



From this it is clear that Jumonji can build up the same 

 quantity of leaves with a far smaller quantity of nitrogen, that 

 is, the necessity for nitrogen must be far smaller than in the 

 other two varieties. Further, we have calculated that Takasuke 

 consumes 6.31 grams reserve nitrogen to produce 1220 grams 

 fresh leaves ( = 266.8 grams dry matter, containing 13.34 grams 

 nitrogen), while in Jumonji only 3.95 grams reserve nitrogen is 

 spent to produce the same amount of fresh leaves ( = 316 grams 

 dry matter, containing 12.64 grams nitrogen). Thus we see that 

 Jumonji needs only 62% or nearly § of the reserve nitrogen re- 

 quired by the other two varieties to produce the same quantity 

 of leaves. This evidently shows that Jumonji has a stronger 

 absorptive power for the nitrogen in the soil and manures, and 

 does not rely upon reserve nitrogen so much as the other two. 

 It is therefore not to be wondered at that, Jumonji is less liable 

 to attack by the disease, since the comparatively small quantity 

 of reserve materials in the roots is soon made good by the newly 

 absorbed nutriments. 



