1912] A. R. Rose 437 



cium phytate has no marked influence. This is apparent from the 

 results in beakers 3-7 (Series I), 16-18 (Series II) and 38 and 42 

 (Series IV). In all these cases, there is only a negligible increase 

 in growth associated with the addition of the phytate. The growth 

 of the seedlings in beaker No. 19 was perceptibly improved, how- 

 ever, when as much as 0.036 per cent. of calcium phytate was added 

 to the mixture used in beaker No, 16. 



In all these trials calcium phytate was comparable with dibasic 

 calcium phosphate (CaHP04). In both salts, the calcium ion 

 seemed to be the agent which stimulated the growth of the root, 

 and the 0.005 per cent. and 0.006 per cent. Solutions were suffi- 

 cient to supply calcium for more than six days' development. 



Besides the calcium salt, magnesium inosite hexaphosphate 

 was also studied in this connection. This Compound had an effect 

 upon root growth similar to that of magnesium sulphate, potassium 

 nitrate and potassium phosphate. Data pertaining to the growth 

 of seedlings in Solutions containing magnesium phytate along with 

 calcium salts, were obtained in Nos. 70-76 (Series VII). These 

 should be compared with Nos. 59-67 (Series VI) in which various 

 combinations of calcium sulphate and calcium nitrate with calcium 

 phosphate and calcium phytate were employed. In Series VII, the 

 average root growth per plant per day, for the first six days, varies 

 from less than 8.5 mm, to 11.4 mm., whereas, in Series VI, grown 

 at the same time, the ränge is from 12 mm. to 16.5 mm. Here the 

 retarding effect of the magnesium phytate is plainly indicated. 



A comparison of the effects of magnesium phytate and magne- 

 sium phosphate has been made in beakers Nos. 96 and 97 (Series 

 IX), calcium sulphate being present in both Solutions. No differ- 

 ence in rate of growth occurred. 



The double salt of calcium and magnesium (a form of phytin 

 very commonly found in plants) was not favorable to root growth. 

 Various strengths of Solution were tried, e. g., o.ooi per cent., 

 0.002 per cent., 0.005 P^^ cent., and 0.0 1 per cent. There were 

 growths of 6.0 mm., 9.4 mm., 10 mm. and 7.4 mm, respectively, per 

 plant per day for the first six days, with apparent cessation of 

 growth on the eighth day. The copper salt was found to be ex- 

 ceedingly toxic. 



