12 
BULLETIN 52, HAWAII EXPERIMENT STATION. 
Growth of Rice in Nutrient Solutions. 
In order to investigate the influence of manganese more fully and 
without the complication of soil phenomena, various experiments 
wore conducted in nutrient solutions with the addition of manganese 
sulphate and manganese dioxid. Rice, which is similar to the pine- 
apple in its susceptibility to chlorosis, was used in these experiments 
because it is more convenient of culture in nutrient solutions and 
furnishes results more quickly than the pineapple plant. 
Experiment I. — This experiment was divided into two series of 
nine tests each, using the nutrient solutions shown in Table 6. 
Table 6. — Nutrient solutions used. 
Series I.— Loew and Sawa's (-33) nutri- 
ent solution. 
Calcium nitrate 
Magnesium sulphate 
Potassium nitrate 
Monopotassium phosphate 
Ammonium sulphate 
Ferrous sulphate 
Quantity. 
Series II.— Gile and Carrero's (17) 
acid nutrient solution. 
Per cent. 
0.04 
.01 
.03 
.02 
.01 
.01 
Weight. 
Grams. 
Potassium nitrate... 0. 1017 
Monobasic potassium phosphate . 0714 
Sodium nitrate . 2143 
Sodium sulphate .0315 
Calcium chlorid . 05 
Magnesium chlorid . .05 
Ferric chlorid .0041 
Sulphuric acid c.c. X/m__ . 5 
Distilled water c.c. 1.000 
The manganese dioxid used in all the experiments was prepared by 
Merck and marked "artificial," and "pure," and contained about 
90 per cent MnO,. Ten grams of this manganese dioxid in 200 
cubic centimeters of pure water gave, on 18 and 42 hours' contact, 
a pH value of about 6.6, or a faintly acid reaction. Coral sand and 
calcium carbonate under the same conditions gave a pH value of 
about 8.4 or a distinctly alkaline reaction. 
Rice seedlings were germinated in distilled water and transferred 
to the various nutrient solutions when the plumules were about 
2 inches long. Four plants each were grown in large flasks. Dupli- 
cate tests of each trial were made. Transpired water was replaced 
with distilled water daily and the solutions were changed every 
fourth day. The solutions were freshly made 18 hours before chang- 
ing and the flasks and roots were rinsed with a little of the fresh 
solution when the changes were made. The plants were grown for 
40 days. 
The plants were harvested on the fortieth day and the green and 
dry weights of the stalks and leaves and of the roots were determined. 
The results are given in Tables 7 and 8. 
