Saburo Okamoto

Effect of mineral nutrition on metabolic change induced in crop plant roots (V): Respiration in sweet potato roots

Abstract In the previous work concerning the effect of potassium nutrition on glycolysis in sweet potato roots (1), monoiodoacetic acid (MIA) and sodium fluoride (NaF) inhibited more strongly respiration in younger roots and root tip parts, and yet a potassium deficiency enhanced its inhibition. The inhibition of MIA, which inhibits triose phosphate dehydrogenase (2), may indicate the importance of the EMP pathway and the Krebs cycle (3,4). The inhibition of NaF, which in higher concentrations inhibits enolase (2), may suggest the importance of the metabolism following phosphoglycerate → phosphoenolpyruvate or the Krebs cycle (3,4). It is of interest, therefore, to elucidate the role of the Krebs cycle in respiration in sweet potato roots, and what significance potassium nutrition has in the Krebs cycle operation. This paper deals with experiments bearing on respiration in roots of sweet potato plants grown at varying degrees of potassium application, especially in the presence of various inhibitors and /...

Effects of potassium nutrition on the glycolysis and the krebs cycle in taro plants

Abstract The previous works (1, 2) with the bleeding sap from taro plants showed that a potassium deficiency altered the amplitude and the period of the diurnal periodicity in exudation process with the roots, and suggested that potassium might be an essential element for an intensive exchange of amino acids between living xylem tissues and xylem sap. The other works (3,4) with excised roots from sweet potato plants grown in a seven days solution culture showed that the relatively K-deficient roots had higher respiratory activities than the normal, especially In the root tip, and accumulated concomitantly higher levels of reducing sugars and amino nitrogen. Recently, however, an increasing number of works (5, 6) has been devoted exclusively to elucidating the relationship between respiratory activity in plant tissues and organic acid metabolism under a relative K-deficiency. In this work the effects of potassium nutrition on the glycolysis and the Krebs cycle in the roots and the leaves of taro plants are...

Effect of mineral nutrition on contents of organic constituents in sweet potato plants during growth

Abstract Although chinese yam plants are an important crop in Japan, relatively little is known about their content of the organic constituents. IZAWA and NATAKE (1,2,3) showed some aspects of the effect of the fertilizer treatment on the organic composition of chinese yam plants at various phase of their vegetation. Many reports on chinese yam plants have appeared; nevertheless, the nature of carbohydrate and nitrogen metabolism has remained unknown. However, there are a number of excellent reports (4, 5, 6) which directly or indirectly have a bearing on these biochemical phase in sweet Potato plants. Therefore, the objectives of the Present study were twofold : a) to determine the contents of sugars, starch, alcohol-insoluble solids, and various nitrogen constituents in sweet potato plants during growth as affected by mineral nutrition, and b) to compare the effect of mineral nutrition on sweet potato plants with its effect on chinese yam plants.

The respiration in the roots of broad bean and barley under a moderate potassium deficiency

Abstract The previous work on the respiration in taro plants (1) suggests that superior activities of the glycolysis and the Krebs cycle in these plant tissues under a moderate K-deficiency may be reduced a) with advancing plant maturation, b) with extended K-deficiency, or c) with increasing damage in the metabolism itself, due to unfavourable treatments. Thus the question arises where a critical point of potassium deficiency resulting in a higher respiration rate compared with its normal status should be set up in each plant species, giving careful consideration to the physiological and environmental conditions of the plant concerned. This work was undertaken in an attempt to compare the effects of potassium nutrition on the respiration in the roots of broad bean and barley with those in a longer term culture of taro plants (1).

Effect of mineral nutrition on metabolic change induced in crop plant roots (iv): Effects of potassium nutrition on glycolysis in sweet potato roots

Recent developments in enzyme chemistry are establishing the significance of potassium as a cofactor for enzymes involved in the respiratory system, especially pyruvic kinase (1–3), or the organic acid metabolism, for example aconitase (4). However, the available literature on the glycolytic system of crop plant roots in relation to potassium nutrition is limited at present. Based on the previous works with bleeding sap (5,6) and excised roots (7) from taro plants, this work was undertaken to gain some information concerning the effect of potassium nutrition on glycolysis in plant roots, especially in view of inhibitory effects of monoiodoacetic acid (MIA) or sodium fluoride (NaF). Another object was to ascertain whether the excised roots used were profitable materials for investigation sin to the effect of potassium nutrition on the metabolic status of crop plant roots.

Yield and chemical composition of red clover and ladino clover as affected by phosphorus and calcium

Abstract In Japan red clover and ladino clover are a popular forage. These clovers are adaptable to a wide range of soil conditions, and respond well to fertilization. They are often grown on relatively infertile soils with the aid of complete fertilizers.1