Effect of iron and manganese on65Zn absorption and translocation in soybean seedlings

Summary Short-term experiments were conducted to determine the effect of varying levels of iron and manganese on⁶⁵Zn absorption by roots and translocation to shoots in soybean seedlings. In 11 hours uptake duration, both iron and manganese depressed the⁶⁵Zn absorption by roots and translocation to shoots. The depression was of higher magnitude at higher levels of iron and manganese (5.0 ppm) in the medium coupled with highest level (5.0 ppm) of zinc concentration. It is concluded that interactions between zinc and iron as well as zinc and manganese occur during absorption and translocation processes.Publication No.1185 under Journal Series of the G.B. Pant University of Agriculture and Technology, Experiment Station, Pantnagar     

The influence of phosphorus,zinc and manganese on absorption and translocation of iron in watercress

Summary Absorption and translocation of iron by intact watercress plants (Rorippa nasturtium-aquaticum (L) Hayek) was studied in short period uptake experiments utilising ⁵⁹Fe labelled ferric chloride. Total translocation of iron was inhibited by increasing levels of phosphorus, zinc and manganese in the nutrient medium; the elevated phosphorus and zinc concentrations enhanced iron absorption into roots, but increased retention of absorbed iron in translocating portions of the plant. High levels of manganese in the medium reduced the initial absorption of iron into the root system.     

Effect of manganese on zinc-65 absorption by rice seedlings and its translocation within the plants

Summary Effect of manganese on absorption and translocation of zinc by rice seedlings was studied in a nutrient solution using radioactive zinc (Zn⁶⁵). With increase in manganese application, zinc uptake decreased in roots, but increased in shoots with an application upto 10 M manganese. Reduction in zinc absorption was more at low rates of zinc application. However, translocation of zinc from roots to shoots increased with manganese application upto 20 M but the increase was more pronounced with an application of 2M zinc only.     

Effect of manganese poisoning on the levels of manganese and iron in rat viscera

Twenty rats were poisoned by manganese inhalation, and sacrificed six months after the first exposure. The tissue concentrations (in microgram/g dry weight) of manganese and iron were found in liver, pancreas, lung, kidney and suprarenal gland for atomic absorption spectrometry in control and experimental animals. The measurements show high tissue concentrations of manganese, especially in liver and pancreas of the experimental animals, as well as a little increase in the tissue concentrations of iron, fundamentally in liver, kidney and suprarenal gland.     

Effect of zinc on translocation of iron in soybean plants

Zinc interfered with translocation of iron from roots to above ground parts of Glycine max. (L.) Merrill var. Hawkeye. During periods in which zinc impeded iron translocation, it also suppressed the production of reductant by roots. Addition of iron, as a ferric metal chelate (iron ethylenediaminedihydroxyphenylacetic acid), to the growth medium overcame the interference of zinc. In the root epidermis, potassium ferricyanide formed a precipitate (Prussian blue) with ferrous iron derived from the previously supplied iron ethylenediaminedihydroxyphenylacetic acid. The reduction of ferric iron was suppressed by zinc.     

Sites of absorption and translocation of iron in barley roots: tracer and microautoradiographic studies

Absorption and translocation of labeled Fe were measured at various locations along the length of intact seminal axes and lateral roots of iron-sufficient (+Fe) and iron-stressed (−Fe) barley (Hordeum vulgare) plants. In seminal axes of +Fe plants, rates of translocation were very much higher in a zone 1 to 4 cm from the root tip than elsewhere in the root. Lateral roots of high rates of translocation were also restricted to a narrow band of maturing or recently matured cells. In −Fe plants the patterns of uptake and translocation were essentially the same as in +Fe plants but the rates were 7- to 10-fold higher. The amount of labeled Fe bound to the root itself was not increased by Fe stress and its distribution along the root seemed inversely related to the ability to translocate Fe.

Microautoradiographic studies showed that most of the iron bound to roots was held in an extracellular peripheral band in which iron seemed to be precipitated. This process may be assisted by microbial colonies but did not depend on them since it was seen, although to a lesser extent, in sterile roots. In zones from which iron was translocated there was evidence that internal root tissues became labeled readily, but as translocation declined with distance from the root tip, radial penetration of Fe appeared to become progressively less. The results are discussed in relation to possible changes in the pH or redox potential of the surface of the root.

     

Effect of CaC03 and iron application on the availability of manganese in light-textured soil

The effect of added CaCO₃ and iron as ferrous sulphate on the availability of various forms of manganese in light-textured soil was studied in laboratory at room temperature. All forms of manganese decrease with increase in added CaCO₃ upto 16%. Application of iron as ferrous sulphate also decreased all forms of manganese. The addition of iron and CaCO₃ together showed additive negative effect on the forms of manganese through various reactions. The increase in the time of incubation decreases manganese extracted with all forms of extractants due to oxidation and hydration of manganese to higher insoluble oxides and hydroxides. Ammoni um acetate (pH 7.0) + 0.1 % hydroquinone extracted highest amount of manganese by reducing some of the higher oxides along with lower oxides.     

Effect of zinc depletion/repletion on intestinal iron absorption and iron status in rats

Iron and zinc deficiencies likely coexist in general population. We have previously demonstrated that zinc treatment induces while zinc deficiency inhibits iron absorption in intestinal cell culture models, but this needs to be tested in vivo. In the present study we assessed intestinal iron absorption, iron status (haemoglobin), red blood cell number, plasma ferritin, transferrin receptor, hepcidin) and tissue iron levels in zinc depleted, replete and pair fed control rats. Zinc depletion led to reduction in body weight, tissue zinc levels, intestinal iron absorption, protein and mRNA expression of iron transporters, the divalent metal ion transporter-1, hephaestin and ferroportin, but elevated the intestinal and liver tissue iron levels compared with the pair fed control rats. Zinc repletion led to a significant weight gain compared to zinc deficient rats and normalized the iron absorption, iron transporter expression, tissue iron levels to that of pair fed control rats. Surprisingly, haemoglobin levels and red blood cell number reduced significantly in zinc repleted rats, which could be due to rapid weight gain. Together, these results indicate that whole body zinc status has profound influence on growth, intestinal absorption and systemic utilization of iron, mediated via modulation of iron transporter expression.     

Effect of algal growth on the availability of phosphorus,iron and manganese in rice soils

Summary Laboratory experiments were conducted to study the effect of algal growth on the change of (I) pH, (II) available phosphorus and (III) solubility of iron and manganese content in five waterlogged alluvial rice soils of West Bengal, India. The results showed that the algal growth initially caused an increase in the soil pH, which later declined to the original value in some of the soils. The available phosphorus content decreased upto 90 days of their growth and began to increase towards the later period of incubation. The drastic fall of water soluble plus exchaneable manganese content of the soils due to algal growth was accompanied by similar increase in reducible manganese content. No appreciable change in water soluble plus exchangeable ferrous iron content was encountered but theN-NH₄OAC(pH 3) extractable iron due to algal growth progressively decreased with the progress of the incubation period.     

Absorption and translocation of foliar-applied iron

The absorption of ⁵⁹Fe³⁺ by the leaves of various plant species was studied. Stomata were found to play a major role in foliar absorption when leaves were totally submerged in treatment solutions, and a correlation was found to exist between stomatal area and absorption. Day treated leaves absorbed much more than did night treated leaves. The use of a surfactant markedly increased absorption. Translocation from treated leaves was demonstrated and was found to vary with species.     

Effects of calcium and sugars on intestinal manganese absorption

An in vivo luminal perfusion technique was used to investigate the influence of Ca, Mg, lactose, and glucose on Mn absorption in different segments of the rat intestine. Mn absorption was determined by measuring disappearance of⁵⁴Mn activity from the perfusion solution containing 0.1 or 0.01 mmol/L Mn. Na and water absorption were also determined. Mn absorption decreased during the first 30 min of perfusion to reach a steady state thereafter. Ca (1 mmol/L) inhibited Mn absorption in the proximal jejunum and in the colon, whereas Mn absorption was increased by Ca in the distal jejunum. Mg (1 mmol/L), lactose, and glucose (25 mmol/L each) had no effect on Mn absorption in the jejunum. These results can be explained by a direct interaction of Mn and Ca during transcellular Ca transport in the proximal jejunum and colon. The reason for the stimulatory effect of Ca in the distal jejunum is unknown.     

Effect of chlorpromazine on central nervous system concentrations of manganese,iron, and copper

Chronic administration of chlorpromazine produced alterations in trace metal concentrations in caudate nucleus, frontal cortex, and cerebellar hemisphere of guinea pigs. Manganese concentration following chronic chlorpromazine rose significantly in the caudate nucleus and cerebellar hemisphere whereas iron concentration rose most significantly in the caudate nucleus. Copper content was decreased in all regions examined. The possible significance of increased manganese and iron in the caudate nucleus is discussed in relationship to the clinical problems of chlorpromazine-induced dyskinesias.     

Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper and manganese by rats

Interest in the beneficial effects of polyphenols, including tannic acid (TA), is increasing, although, these compounds also have adverse effects; for example, on the absorption of iron (Fe), and possibly other trace minerals. We examined the effect of a graded dose of TA on the absorption of Fe and compared with that of zinc (Zn), copper (Cu) and manganese (Mn) in rats. We also investigated the effect of TA on cecal fermentation which plays a role in absorption. In Experiment 1, to set the optimum dose of Fe, male Sprague-Dawley rats (weighing 70-90 g) after acclimatization were fed with different levels of dietary Fe (5, 10, 20, 30 and 35 mg/kg). We observed that the hematocrit (Ht), serum Fe concentration and transferrin saturation (%) were each reduced in those rats fed less than 20 mg/kg Fe in a dose-dependent manner. In Experiment 2, the rats were fed with test diets containing the minimum required level of Fe, 30 mg/kg diet, with (5, 10, 15 and 20 g/kg diet) or without TA for a period of three weeks. Feeding a diet containing more than 10 g TA/kg diet, but not 5 g TA/kg diet, reduced the hemoglobin concentration (Hb), Ht and serum Fe concentration due to decreased Fe absorption. In contrast, the Zn, Cu and Mn absorption was not affected by TA feeding. It is also demonstrated that liver Fe, but not the Zn, Cu and Mn contents, were lower in the TA groups than in the TA-free control group. Feeding TA slightly decreased the pH value of the cecal contents with an increase in the major short-chain fatty acid pool. About 15% of the ingested TA were recovered in the feces of each TA-fed group. Our results demonstrate that more than 10 g TA/kg diet induced anemia by reducing the Fe absorption, although there was no effect on the absorption of other important trace minerals. Our findings suggest that the usual intake of polyphenols is relatively safe, but that a high intake by supplementation or by dietary habit of tannin affects only the Fe level.     

Effect of orally-administered epidermal growth factor on intestinal iron absorption and mucosal permeability

A progressive increase in intestinal 59Fe3+ absorption was observed on oral feeding of mice with physiological doses of EGF/UGO. Maximal changes were apparent after 3d and appeared to be dose-dependent. In addition to a small increase in intestinal cell proliferation, as reflected by increased ornithine decarboxylase activity, EGF/UGO-feeding increased mucosal permeability (evaluated with [51Cr]-EDTA): the latter could account for the increase in iron absorption. Sialoadenectomy, to remove the major source of endogenous EGF/UGO, had no appreciable effect on the intestinal absorption of iron.