Nov. 17,1923 
Absorption of Carbon by the Roots of Plants 
CONCLUSIONS 
(1) The presence of sodium or ammonium nitrate, or of calcium, 
sodium, or potassium carbonate, in culture solutions for wheat seedlings 
is followed by the presence of carbonates in the ash of the plants. 
(2) When sodium nitrate, for example, is present in the culture solu¬ 
tion the plants seem first to absorb the N 0 3 ion, leaving in the solution 
some sodium which combines with the water and with the C 0 2 dissolved 
in the solution to form sodium carbonate or bicarbonate. This in turn 
gives up its C 0 3 to the plant. 
(3) The plant absorbs C0 3 by means of its roots. 
(4) The plant probably absorbs C0 3 as an ion, or exudes C0 2 , for 
the purpose of maintaining equilibrium in its tissues or in the nutrient 
solution. 
(5) Wheat plants do not seem to be able to absorb C 0 2 from its solu¬ 
tion in water without the presence of a soluble base. 
(6) The absorption of a basic radical, potassium for example, seems to 
depend largely upon the absorption of an acid radical. 
(7) There is a possibility that the term “lime-loving” as applied to 
to plants, might more properly be “carbonate-loving.” 
