206 
Smith and B idler. — Relation of 
time the plants in the full nutritive solution were coming into flower and 
the inflorescence showed colour ; the plants had four nodes and the ultimate 
leaf was unfolding. The plants growing in the absence of potassium, on the 
other hand, had stagnated since the twelfth day, and possessed but one short 
internode and a miniature leaf ; the root system was also dwarfed, but other- 
wise resembled that of the plants growing in the full nutritive solution. 
Table XVIII. Green and dry weights of Japanese buckwheat grown 
in water cultures free from and- containing potassium. 
Nutritive potassium 
No. of 
Total weight 
of plants. 
Dry weight of j 
Ratio of 
tops to 
roots. 
used. 
plants. 
Green. 
Dry. 
Tops. 
Roots. 
Grm. 
Grm. 
Grm. 
Grm. 
Nutritive -solution F 
4 
8-052 
0-8692 
0-8181 
0-0511 
4 
9.186 
0.9250 
0-8698 
0.0552 i 
4 
10-665 
1-0609 
0.9941 
0-0668 
4 
11-067 
1.1388 
1.0839 
0*0549 
Mean 
i 
2.436 
0-2496 
0-2354 
0.0142 
16-5 
Nutritive solution F, 
4 
0-986 
0.1300 
0-H75 
0-0125 
less potassium. 
4 
0.834 
o-i 281 
0-H93 
0.0088 
4 
0-682 
0-0869 
0.0824 
0-0045 
| 
4 
0.678 
0-1038 
0-0950 
0-0088 
Mean 
i 
0.199 
0-0281 
0.0259 
0-0020 
i 12.9 
Table XIX. Amount of and distribution of potassium in Japanese buck 
wheat grown in water culture free from and containing potassium. 
Nutritive solution 
used. 
4 > 
Nutritive solution F 
Nutritive solution F, 
less potassium 
No. of 
plants. 
1 
Amount of potassium j 
in 
1 
Tops. 
Roots. 
Entire 
plants. 
Mg. 
Mg. 
Mg. 
16 
J 16 
21 2.70 
2.60 
24.30 
1.40 
to 
-lx 
6 6 
Potassium 
utilized per 
gramme of dry 
matter 
formed. 
Tops. Roots' 
Total 
potas- Potassium 
Ratio of slum absorbed 
potas - utilized from the 
per nutritive 
gramme solution 
of dry by one 
matter plant, 
formed . 
sium 
content 
of tops 
to 
roots. 
Mg. 
Mg. ! 
Mg. 
Mg. 
Mg. 
56.48 106.60 1 
0.52 
59*34 
J 4*74 
6.28 
40.46 
0.15 
8.91 
0.18 
I 
The green and dry weights of the plants are given in Table XVIII. 
A glance at the table shows that in the absence of potassium the dry 
weight of the buckwheat plants was 8-8 times less than that of the plants 
growing in the full nutritive solution. But it will be noticed that, contrary to 
what was found in the case of the wheat and corn, absence of potassium 
does not disturb the relative growth of tops and roots. 
The distribution of potassium in the plants is shown in Table XIX. 
