根の特性からみた栽培稲品種 : VI. 鉄被膜形成と三要素吸収

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As is reported in the previous papers (1959 a & b), amounts of ferreous coatings in rice roots, both per plant and per unit surface area, increased up to the period of heading, having kept pace with the growth advance. In contrast to those changes, the relative growth rate of root weights dropped progressively. Amounts of ferreous coatings were also larger in those plants of which the root development was vigorous. Moreover, when roots were forced to age artificially, they produced much more coatings. In addition to these results, from the authors' determinations of the cation exchange capacity of roots of several varieties, it was made clear that the capacity was almost proportional to the amounts of ferreous coatinges. If the values of the capacity indicate the exchan geability of cations on root surface and the possibility of the absorption of those ions by roots, it may be suggested that the ferreous coating formation must be related to the nutritional uptake, including both anions and cations. In this investigation the authors tried to decide the relation mentioned above and to clarify the physiological significance for the ferreous coatings. Those varieties such as Norin 1, 41, 37 and 69 were planted without transplanting in paddy field of which soil is of sandy loam and of good drainage. Sampling was done every 15 days after planting, but at the harvest time it was conducted at the yellow meturation stage of each variety. In all samples the plant growth and contents of N, P and K were analysed and estimated in both top and underground parts. In the underground part, the ferreous coatings were quantitatively determined. Main results and some discussions concerned were as follows. 1) In each variety, ferreous coatings, total contents of the three elements and dry weights, respectively per plant, went upwards hand in hand as the growth advanced, until the period of heading (Fig. 1). Moreover throughout all stages of the growth and among all varieties used, the amounts of coatings were nearly proportional to the content of each element. These facts might be, however, interpreted as the accidental phenomena accompanying with the growth processes. Both factors such as the time and growth which affect the phenomena, must be therefore eliminated from those data obtained, inorder to make clear the relations among thern. 2) The time factor can be removed by caluculating those quantities per unit time, with such formulae as shown in Tab. 2. Fig. 2 shows the parallel relations among those per unit time. 3) This holds also for the elimination of the growth factor by calculating the relative rates of those quantities respectively. Formulae used for the calculations are also shown in Table 2. These relative rates changed quite parallely during the course of the growth (Fig. 3). Moreover the positive correlations between the rate of the coating formation and that of the absorption of each element were found (Fig. 4). Thus the anthors came to a conclusion that the ferreous coating formation was in a close connection with the nutritional uptake uptake and the plant growth. The ferreous coating formation may originate first from the oxidation of ferrous ions by roots at the interspace between roots and soils. Then the ferric ions may be exchanged and adsorbed on root surface to produce the coatings. The nutritional absorption may also be enhanced by the surface exchange and the oxidation in roots. Thus there may be some theoretical coincidence which justifies the experimental results. 4) Amounts of the ferreous coatings may be affected by the total root surface area at the time of the measurement and also by the integrated physiological activities favorable for the coating formation in roots. A formula such as Fe=A×∫f shows this connection. From this formula, 1/(Fe|A)=1/(∫f) is derived. This signifies that the reciprocal of the amounts of coatings per unit surface area becomes smaller when summed functions in roots increases. Thus
日本作物学会の論文
1961-01-20

根の特性からみた栽培稲品種 : VI. 鉄被膜形成と三要素吸収

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