Abstract
Mineralization and absorption of soil ogranic phosphorus by plant root were investigated, using diluted alkaline extract of soil. Results obtained are as follows. 1. Phosphatase activities in root-cap cell, coating root tip of corn, and also degraded roots of barley and rice plant, were found to be very high. In the course of degradation of root, this activity increased until maximum was attained and then decreased (Table l, 2). 2. It was recognized that phytin-inosit was absorbed by barley or rice plant in the same magnitude as that of phytin-P. This fact seemed to suggest that phytin was absorbed by root without any dephosphorylation (Table 3). 3. Organic phosphorus extracted by 0.5 NNH_4OH from two soils was hardly mineralized by excised roots of barley and rice seedlings (Table 4), while this phosphorus was slightly utilized by the intact roots of the same plants. But it was obscure whether the above phosphorus was absorbed as such or mineralized before it became available (Fig l).
