Shingo Mitsui

The uptake of strontium and cesium by plants from soil with special reference to the unusual cesium uptake by lowland rice and its mechanism

Abstract In the previous experiments using strontium-90 and cesium-134, the authors found some differences between lowland and upland rice with respect to their uptake from soil, particularly the unusual high absorption of cesium by lowland rice.

The effect of pesticides on the denitrificatitn in paddy soil

Abstract The formation of nitrate in paddy fields is undesirable, because it will be lost through denitrification or leaching. Drained condition before flooding encourages the formation of nitrate, the loss of which after flooding is inevitable.

The intake and utilization of carbon by plant roots from 14C-Labelled Urea. Part IV

Abstract Whether urea can be utilized as a direct nitrogen source for the growth of higher plants or not, has been studied by many investigators. Such studies conducted with plants in sterile media provide evidences that many higher plants can utilize urea-nitrogen.1) Yamaguchi 2) observed that, when maize seedlings were grown in sterile culture with, the urea was detected in the shoots and even in gutation water. More recently, Bollard et al 3,4) f a so etected urea in the xylem sap extracted from young apple trees grown in sand, to which urea was supplied. Similar findings were established in wheat seedlings5) and in rice plants4).

Nutritional Study of Silicon in Graminaceous Crops (Part 1)

Abstract Silicon in crop plants has been studied in various ways, for example, in elucidating its effects on phosphorus and nitrogen uptake by roots, or increase of resistance to diseases and insect pests, Graminaceous crops generally contain much more silicon in them than other families of plants, Remarkable effects of silicon application to plants On their growth appear especially in case they have contained about 5 to 10% of silicon before-hand. When silicon content in plants, on the other hand, is quite low, such as less than 0.5% for dry matter, plants show retardation of their grOwth at both vegetative and reproductive stages. It may be deduced that silicon applied to plants might play a role in different ways in cases where they have already had either considerable or quite small amounts of silicon. While the former case has been studied very much, extreme deficiency of silicon in plants has been investigated very little1)-8). Experiments reported here were designed for elucidating roles of silicon...

ABSORPTION OF RADIOACTIVE STRONTIUM BY SOIL, ESPECIALLY IN RELATION TO NATIVE CALCIUM.

Abstract Since it has been well known that radioactive strontium, among the fission nuclides, is particularly important in respect to the potential biological radiation hazard, much attention has been given in recent years to the study on its behaviour in soil and plant. The experiments described herein were conducted in order to elucidate some of the features of carrier-free radioactive strontium added to soils especially in connection with native calcium.

On the utilization of carbon in fertilizers through rice roots under pot experimental condition

Abstract Kursanov et al. conducted a series of studies on the CO2 uptake by roots and translocation and uilization in plant, using carbon-l4 labelled CO2. Kursanov, Kuzin and Mamul1) first studied the uptake of CO2 by the roots of intact bean seedlings and found that after 18-hours exposure in the light, most of the radioactive carbon was translocated upwards. Later on, in a more detailed paper2) these Russian workers estimated that under their experimental conditions, the amount of CO2 absorbed by roots is as much as 25 per cent of that taken up from the atmosphere by leaves. They also reported that soluble carbonates supplied as a fertilizer increased the yield of bean, barley, potato and sugar beet by 15 to 18 per cene). In addition Grinfeld 4) stated that 30–50 kg of CO2 per hectare, dressed as ammonium carbonate, increased the yield of sugar beet by 7 to 16 per cent.

Dynamic aspects of N.P.K. uptake and O2 secretion in relation to the metabolic pathways within the plant roots

Abstract As previously reported1)-4) the inhibition of nutrients uptake by rice plant with such respiration inhibitors as hydrogen sulfide, butyric acid, cyanide, and azide differed strikingly from element to element. The order of suppression, however, was similar in these respiratory inhibitors, and the Ce I Itlon coefficients as revealed in terms of percents of decrease were grouped in the order of K2O·P2O5>SiO2·SO3·Br>MnO·NH4-N·H2O2> MgO·CaO. This established order attracted the authors interest to elucidate the essential mechanism of the uptake of each element, possibly linked specifically with metabolic pathways, particularly of respiration, within the plant roots. In view of the prime importance of three major fertilizer elements N.P.K., the specific metabolic linkages of these three elements were subjected to a energetic study.

COMPARATIVE PHYSIOLOGICAL STUDY OF IRON, MANGANESE AND COPPER ABSORPTION BY PLANTS : III. Interaction between Fe, Mn and Cu on the Absorption of the Elements by Rice and Barley Seedlings

Abstract In the previous reports, influence of metabolic inhibitors, such as NaCN, 2,4-dinitrophenol and EDTA, on the absorption of 59Fe, 54Mn and 64Cu(1) and the distribution of these elements in root cell were studied using the separation technique by centrifugal forces (2). These experiments revealed that rice and barley plants behave differently in their mode of absorption and distribution of these elements.

SOIL ADSORPTION OF UREA II : An infra-red spectrophotometric analysis for a mechanism of adsorption of urea

Abstract Soils have generally been considered to adsorb little amounts of urea because it scarcely dissociates in water solution. A few works1-3) have been reported on this problem. But it should be noticed that an electrostatic adsorption might not be the sole mechanism of soil adsorption of urea. In the previous paper4) a correlation between equilibrium concentrations of urea in soil solutions and the amount of adsorbed urea was worked out, using Tanashi paddy soil of volcanic ash origin. An adsorption coefficient of Urea on the soil was calculated from the correlation and it was suggested that the soil possibly adsorbed considerable amounts of urea by a force which was weaker than the electrostatic force. together with experiments4) using urea derivatives such as thiourea, methylurea or dimethylurea, it was concluded that the soil adsorption of Urea was possibly due to the formation of hydrogen bondings, principally arising from amino hydrogens and partly from carbonyl oxygen in a urea molecule.

Soil adsorption of urea: I. On the mechanism of adsorption of urea

Abstract Since urea itself scarcely dissociates in water solution, it has been vaguely considered that soil adsorption of urea is so little that the amount of nitrogen adsorbed is almost negligible as compared with ammonium salt. But possibly a considerable quantity of urea may be adsorbed in any other manner than the ion adsorption which occurs in the case of ammonium ion.