Abstract
In connection with Part 10 of this series of study, the base exchange capacities and ultimate pH of various plant roots were measured. The methods employed by Mattson or Drake were more or less modified on the procedures of electrodialysis and titration. The schema of the apparatus for electrodialysis employed in this study is shown in Fig. 1. The fresh root samples were directly electrodialysis until the electric current lowered approximately to 0.01-0.02 Amp., neutral red as indicator. To put the results on the comparable basis approximately five minutes were necessary for thc neutralisation to pH 7. After filtration in about 30 seconds with glass filter, 100 cc of the filtrate was added with excess acid, boiled five minutes to drive off carbon dioxide and final]y titrated back with alkali, utilising methyl-red as indicator. The base exchange capacities and ultimate hydrogen ion concentrations thus obtained are shown in Table 1. Three two parameters coincided fairly well as given in Fig. 3. The figures were highly significant on 1% level between legumes and cereals in agreement with the results obtained by MATTSON or DRAKB.
