1918] CURRENT LITERATURE 571 
more abundantly in the upper parts of the trees, and are the cause of increased 
sap concentration. Any agreement between observed increments of osmotic 
pressure and theoretical values calculated from the increased hydrostatic head 
and resistance to be overcome in the tracheae by virtue of higher position is 
regarded as a coincidence, and not as a proof of adjustment on the part of the 
cells to the back pull of increased head and resistance-—CHARLES A. SHULL. 
Antagonism.—Antagonism between iron and manganese in their effects 
on the growth of two varieties of wheat has been investigated by TorriIncHAM 
and Beck.“ Manganous chloride in water cultures even in low concentrations 
reduces root growth, but when ferric chloride is added in about equimolecular 
(0.00001 M) concentration the deleterious effects of the manganous salt are 
overcome. The two varieties of wheat used did not give exactly the same 
results, and it is believed that effects will depend on variety to a certain extent. 
Thus the amount of reserve iron in the seed would influence the response of 
the plant to variations in supply of salts of these two metals. In very dilute 
solutions the manganous chloride seemed to have stronger effects than ferric 
chloride on the color and growth, while in higher concentrations (0.001M) the 
iron salt had more effect than the manganese. Although the concentrations 
used approach that of these salts in the soil solution, no conclusions as to 
antagonism in soil cultures can be drawn because of the great variety of other 
salts ~ iim which might modify the result. 
S YER has studied the effects of manganese sulphate and some other 
inorganic | bce in overcoming the unfavorable action of vanillin and 
salicylic aldehyde on plants grown in culture solutions of varying composition. 
e finds that vanillin reduces the growth of cow peas, but the presence of nitrate 
reduces the unfavorable action, and may even entirely overcome the reduction 
of growth caused by vanillin. The harmful effects of salicylic aldehyde in 5 
and to ppm. concentrations on wheat seedlings were entirely overcome by 
manganese sulphate in ro ppm. concentration; and the harmfulness of vanillin 
was also partially overcome by manganese sulphate. He explains the action 
of nitrate and manganese on the ground that they favor root oxidation, whereby 
the harmful organic compounds are oxidized and are not permitted to influence 
growth unfavorably.—CHARLES A. SHULL. 
The embryo sac of Aster and Solidago.—These much investigated embryo 
sacs have been studied again, this time by Patm,” a pupil of ROSENBERG. 
™ ToTTINGHAM, W. E., and Beck, A. J., oe between manganese and iron 
in the growth of wheat. Plant World 19:359-370 
15 SKINNER, J. J., The effect of vanillin and agree Z adtides in culture solution 
and the action of chemicals in altering their influence. Plant World 19:371-378. 
1916. 
6 Parm, BJ., Zur esi der Gattungen Aster und Solidago. Acta Horti 
Bergiani 5:1~18. figs. 27. 
