Potassium to Growth in Plants. 
225 
Summary. 
1. The reserve supply of potassium in the seed is not sufficient to 
maintain normal growth except for a very short period of time. 
2. Symptoms of potassium starvation appear early in the life of 
a plant, and are characterized by a dwarfing of the axis and progressive 
death of the foliage, the older leaves succumbing first. 
3. The potassium absorbed per gramme of dry matter formed is higher 
in plants growing in the presence of potassium than in plants growing in its 
absence. 
4. Recovery from potassium starvation occurs the more slowly the 
longer potassium is withheld. 
5. The relative distribution of potassium per gramme of dry matter 
formed as between tops and roots is the same whether the plants are 
growing in the presence of potassium, in the absence of potassium, or 
have first suffered from a more or less prolonged period of starvation. 
6. When potassium-starved plants are supplied with potassium the 
element becomes distributed promptly in accordance with the physiological 
needs of the plant, the absorption progressing with marked rapidity. 
7. The normal life cycle is inhibited in potassium-starved plants and 
more or less delayed by partial potassium starvation. 
8. The relative potassium requirement per gramme of dry matter formed 
as between the tops and roots is the same in the case of wheat and corn, but 
in the case of buckwheat the requirement of the roots is higher than that 
of the tops. 
9. The amount of potassium utilized per gramme of dry matter formed 
in normal plants of wheat and corn is substantially the same. 
10. The amount of potassium utilized per gramme of dry matter formed 
in wheat and corn plants growing in the absence of potassium is substantially 
the same. 
11. The amount of potassium utilized per gramme of dry matter formed 
in buckwheat growing in the absence of potassium is higher than in the case 
of wheat and corn. 
12. The amount of potassium contained in the seed does not in itself 
determine the length of time a plant grown from it can live in the absence of 
potassium without injury resulting. 
Q 
