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AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
3. The absolute weight of green material, dry raatter, and ash was 
determined for the tops, roots, and total plants in each culture. The ash 
content was expressed in percentage of green weight and dry weight. 
4. The effects of reduced transpiration upon the total ash content of 
the plants used in these experiments depended upon how transpiration was 
reduced. 
5. Under the conditions of these experiments, with a uniform concen- 
tration of nutrient solution, the total ash content of barley plants varied 
but slightly even though the quantity of water transpired was reduced to 
less than one half by increasing the atmospheric humidity. On the other 
hand, in plants in which the transpiration was reduced to less than one 
half by shading and the photosynthetic activity was also reduced, thus 
reducing the available food, the total ash content was also correspondingly 
reduced. When the total transpiration was reduced by increasing the 
concentration of the nutrient solution, the total ash content was only 
slightly reduced. 
6. The ash content expressed in percentage of total dry weight of the 
whole plants varied but slightly, regardless of whether the plants were 
grown under conditions of high or of low transpiration and irrespective of 
how transpiration was reduced. 
7. , These results do not support the theory that transpiration has an 
important role in supplying plants with nutrient salts. The results of this 
investigation seem to indicate that, there being no other limiting factor, 
the amount of food available which would allow for growth, in which process 
nutrient salts are used, is an important factor in determining in how large 
quantities or how rapidly the essential salts enter the plant. Analyses for 
ash content indicate that there is little or no relation between transpiration 
and the absorption of salts in barley plants. 
This investigation was suggested by and conducted under the direction of 
Professor O. F. Curtis, to whom the writer is indebted for helpful advice 
and a constant interest shown throughout its progress. 
Laboratory of Plant Physiology, 
Cornell University 
LITERATURE CITED 
Burgerstein, A. Ueber die Transpirationsgrosse von Pflanzen feuchter Tropengebiete. 
Ber. Deutsch. Bot. Ges. 15 : 154-165. 1897. 
Curtis, O. F. The upward translocation of foods in woody plants I. Tissues concerned 
in translocation. Amer. Jour. Bot. 7 : 101-124. 1920. 
Fittbogen, J. Untersuchungen iiber das f iir eine normale Production der Haferpflanze not- 
wendige Minimum von Bodenfeuchtigkeit sowie iiber die Aufnahme von Bestand- 
teilen des Bodens bei verschiedenen Wassergehalt desselben. Landw. Jahrb. 2 : 
252-371. 1873. 
Giltay, E. Vergleichende Studien iiber die Starke der Transpiration in den Tropen und in 
mitteleuropaischen Klime. Jahrb. Wiss. Bot. 30 : 615-644. 1897. 
