20 
BULLETIN 52, HAWAII EXPERIMENT STATION. 
The results of Experiment IV are similar to those of Experiment 
III. Manganese dioxid with 5, 10, or 20 milligrams per liter of iron 
supplied as ferric chlorid and 18 milligrams per liter of manganese as 
manganous sulphate (0.005 per cent manganous sulphate) caused 
chlorosis and a severe depression in growth. When the leaves were 
dipped in iron solution the chlorosis was largely overcome but normal 
frowth was not fully induced. Very dark green spots formed on the 
ipped leaves where the iron penetrated. The chlorotic effects of 
& /O 20 40 SO 
M/LUG#tfMf OF '//eO/V P£% Z/7Z/P &//>/*./&? TO TH£ 
Fig. 3.— (Results of Experiment V.) Effect of manganous sulphate and maganese dioxid on the growth 
of rice in nutrient solutions supplied with various amounts of iron from ferric citrate. 
manganese were completely overcome when the amount of iron in 
the solution was increased to 40 and 80 milligrams per liter, but the 
checks were injured by this amount of iron from ferric chlorid. 
Manganese dioxid, by its removal of some of this excessive iron, gave 
slightly better results than the check. 
Experiment V. — This was a repetition of Experiment III. The 
different variables were the same as in Experiment III except that 
