Physiological and Ecological Studies of Rice Plant in Well-drained and Ill-drained Fields. : (6) Changes of some constituents in root of rice plant.

Abstract

The authors investigated constitutional changes of rice root cultured in well-drained and ill-drained paddy fields. 1) By the phenol method and spodogramm hydrogen chloride treatment method, remarkable amounts of silica were found absorbed on the epidermis and outside of the central cylinder of rice root. 2) By phenol method, we supposed that iron and silica deposited together on root epidermis and that certain cells of root epidermis were especially rich in iron and silica as compared with others. (Fig. 3) And by spodogramm hydrogen chloride treatment we found the silica of epidermis of rice root to be of indeterminate form as shown in Fig. 4 and Fig. 5. 3) By spodogramm hydrogen chloride treatment we found that the outside of central cylinder of rice rice root was silicified and that silica of central cylinder showed cell shapes like that of leaf blade and not like the epidermis silica of root. (Fig. 7, 8, 9, ) 4) According to analytical results, iron and silica were rich in well-drained rice root compared with ill-drained rice root, and well-drained rice root showed a tendency to increase iron and silica at late growth periods, but ill-drained rice root showed rather decreases of those components at late periods. 5) In order to correct the percentage values of constituents against the soil residua in root sample, calculation was made by the formula as follows: [constituent weight/sampling weight-(iron weight+silica weight)x100] 6) Soluble nitrogen was rich in ill-drained rice root as compared with well-drained rice root, but differences in protein nitrogen contents was not recognized, and protein nitrogen in rice root decreased in late growth periods, while soluble nitrogen did not changed according to the growth. 7) Phosphate decreased in late growth periods, and well-drained rice root was rich in phosphate as compared with ill-drained rice root. 8) It is considered that iron, silica, and phosphate contents in rice root had a positive correlation to root metabolic capacity, and soluble nitrogen had a negative correlation. By studies on constitutional changes in rice root cultured under various conditions it would be able to make clear the physiological functions of the organ.