Molybdenum in the Biosphere
Molybdenum in plants
Impacts of Mo application on biological nitrogen fixation and diazotrophic communities in a flooded rice-soil system
Molybdenum (Mo) deficiency in the farmland of China may limit biological nitrogen fixation (BNF), however, the impact of Mo application on BNF capacities and diazotrophic communities in rice-soil systems is unclear. In this experiment, treatments in a 6.7atom% (15)N2-labelling field-based growth chamber for 74days and treatments in a 99 atom% (15)N2-labelling microcosm experiment for 40days combined with 16S rRNA gene sequencing and DNA-stable isotope probing (SIP) were used to investigate the impacts of Mo application on BNF and diazotrophic communities. Our results showed that under the condition that no nitrogen (N) fertilizer was applied, Mo application (500gsodiummolybdateha(-1)) significantly increased N2 fixation in a rice-Inceptisol system, from 22.3 to 53.1kgNha(-1). Mo application significantly increased the number of nifH gene copies and the relative abundance of cyanobacteria in both growth chamber and microcosm experiments. Among cyanobacteria, the relative abundances of the most abundant genera Leptolyngbya and Microcoleus were significantly increased by Mo application. (15)N2-DNA-SIP further demonstrated that Leptolyngbya and Microcoleus incorporated (15)N2. Mo application greatly increased BNF in Mo-deficient paddy field (</=0.068mgkg(-1)) and stimulated the growth of cyanobacteria. These results indicated that Mo application in Mo-deficient paddy field could be a useful measure to increase soil N input under no N fertilization.
J. Ma, Q. Bei, X. Wang, P. Lan, G. Liu, X. Lin, Q. Liu, Z. Lin, B. Liu, Y. Zhang, H. Jin, T. Hu, J. Zhu, and Z. Xie, Impacts of mo application on biological nitrogen fixation and diazotrophic communities in a flooded rice-soil system, Sci Total Environ, 2018, 649, 686-694.
Metabolomics analysis reveals potential mechanisms of tolerance to excess molybdenum in soybean seedlings
Most plants exhibit strong tolerance to excess molybdenum (Mo). However, the metabolic profile and tolerance mechanisms of plants in response to excess Mo remain unknown. We comprehensively analyzed changes in the metabolic profiles of leaves and roots in soybean (Glycine max L.) seedlings cultured under normal-Mo and excess-Mo conditions by using ultra performance liquid chromatography (UPLC) combined with MS/MS (mass spectrometry). There were 42 differential metabolites in the roots and 19 differential metabolites in the leaves in response to excess Mo stress. In roots, the organic acids, levels of gluconic acid, D-glucarate and citric acid increased by 107.63-, 4.42- and 2.87-folds after excess Mo exposure. Several hormones (salicylic acid, jasmonic acid) and lipids (PG, MG, DG etc) also increased significantly under excess Mo condition. Metabolites related to ascorbate-glutathione metabolism and flavonoid and isoflavone biosynthesis notably accumulated in roots. Only lipid metabolism and salicylic acid accumulation were induced in leaves under excess Mo stress. It is speculated that organic compounds such as 2-oxoarginine, L-nicotine, gluconic acid, D-glucurate, and citric acid played important roles to chelate Mo and reduce its toxicity. Signaling molecules (JA, SA, and some lipids) and non-enzyme antioxidants such as flavonoids/isoflavones act synergistically to detoxify ROS and contribute to Mo tolerance in soybean seedlings. More metabolic pathways were induced by Mo excess in roots than in leaves, suggesting that roots play more implant role in Mo tolerance.
S. Xu, C. Hu, S. Hussain, Q. Tan, S. Wu, and X. Sun, Metabolomics analysis reveals potential mechanisms of tolerance to excess molybdenum in soybean seedlings, Ecotoxicol Environ Saf, 2018, 164, 589-596.
Impacts of trace element addition on lentil (lens culinaris l.) agronomy
Adequate supply of micronutrients is important for the proper growth and yield of lentil, particularly in poorly fertile soil. This study was carried out to understand the effects of zinc (Zn), boron (B), and molybdenum (Mo) on the growth and yield of lentil, and how these elements can help manage soil fertility issues. In this regard, the morpho-physiological traits of lentils (BARI Masur-7) were collected from two experiments receiving the same treatments carried out during consecutive rabi seasons of 2015-2016 and 2016-2017. The experiments were laid out with a randomized complete block design having eight treatments, and was replicated thrice. The treatments were T-1 (Control), T-2 (Zn-2.0 kg ha(-1)), T-3 (B-1.5 kg ha(-1)), T-4 (Mo-1.0 kg ha(-1)), T-5 (Zn2.0B1.5 kg ha(-1)), T-6 (Zn2.0Mo1.0 kg ha(-1)), T-7 (B1.5Mo1.0 kg ha(-1)), and T-8 (Zn2.0B1.5Mo1.0 kg ha(-1)). The results revealed that the application of micronutrients either singly or in combination had significant effects on the plant height, number of branches per plant, number of pods per plant, number of seeds per pod, thousand seed weight, and the seed yield of lentil. The maximum seed production was, however, observed in plots receiving treatment T-8, i.e., the combined application of Zn, B, and Mo. Agronomic biofortification also had significantly increased protein content of lentil seeds while affecting the macro and micronutrient content of lentil seed. These results suggest that any micronutrient deficiencies might lead to a yield loss of lentil, and such a scenario could be avoided by a combined application of micronutrients at a proportionate level.
M. M. Islam, M. R. Karim, M. M. H. Oliver, T. A. Urmi, M. A. Hossain, and M. M. Haque, Impacts of trace element addition on lentil (lens culinaris l.) agronomy, Agronomy-Basel, 2018, 8.
Differential influence of molybdenum and tungsten on the growth of barley seedlings and the activity of aldehyde oxidase under salinity
The influence of molybdenum, tungsten on germination and growth of barley Hordeum vulgare L. was studied. Results of this study revealed the differential effect of heavy metals on seedlings growth. Exogenous molybdenum treatment stimulated the growth of seedlings. The addition of the metal significantly stimulated root elongation. Contrastingly, the addition of tungsten resulted in increased seed germination and inhibits the growth of seedlings. The negative effect of tungsten on the growth of barley was more profound for roots of plants. In addition, the influence of metals on the growth of plants was also tested in saline conditions. It is shown that under salinity stress plant growth drastically decreased in presence of tungsten. Results of this study showed that activity of molybdenum-containing aldehyde oxidase (AO; EC 188.8.131.52) was also significantly affected by metals. The activity of AO in leaves and roots enhanced with increasing concentrations of molybdate, while tungstate treatment inhibited the enzyme activity. Perhaps, the differential influence of molybdenum and tungsten on the growth of barley is a direct effect of metals on aldehyde oxidase activity in plants. Moreover, the intense negative effect of tungsten treatment on barley growth under salinity conditions emphasizes an important role of aldehyde oxidase in plant resistance to stress factors.
Z. Batyrshina, T. M. Yergaliyev, Z. Nurbekova, N. A. Moldakimova, Z. K. Masalimov, M. Sagi, and R. T. Omarov, Differential influence of molybdenum and tungsten on the growth of barley seedlings and the activity of aldehyde oxidase under salinity, J Plant Physiol, 2018, 228, 189-196.
The response of 12 different plant materials and one mushroom to Mo and Pb mineralization along a 100-km transect in southern central norway
Along a transect crossing the Oslo rift Mo and Pb mineralizations occur, among them the Nordli Mo and the Snertingdal Pb deposit. In total 15 different sample media (soil C and O horizon and 13 plant materials) were collected at each of 41 sites along a c. 100-km transect to the north of Oslo and analysed for 53 chemical elements. The responses of 12 different plant media (birch, spruce, cowberry and blueberry leaves and twigs, fern, horsetail and pine bark) and one mushroom (rufous milkcap) to the mineralization and lithological changes along the transect were studied. Most sample materials show a clear reaction to the mineralization, horsetail emerges as the plant that provides the strongest signal and milkcap is the sample medium least suited for mineral exploration. Birch and cowberry emerge as the best compromise for biogeochemical exploration in terms of signal strength and widespread availability in Norway. The uptake of many elements in the plants is strongly controlled, surprisingly few elements indicate the major lithological changes along the transect, e.g. the presence of the Oslo Rift. Most plants react strongly to the presence of Pb mineralization, this can be due to direct uptake or to deposition of local soil dust but cannot be attributed to long range atmospheric transport.
C. Reimann, P. Englmaier, B. Flem, O. A. Eggen, T. E. Finne, M. Andersson, and P. Filzmoser, The response of 12 different plant materials and one mushroom to mo and pb mineralization along a 100-km transect in southern central norway, Geochemistry-Exploration Environment Analysis, 2018, 18, 204-215.
Heavy metals and metalloids: Sources, risks and strategies to reduce their accumulation in horticultural crops
Food production in areas contaminated with heavy metals is associated with health risks because of their adverse effects on food safety and marketability, and on crop growth and yield quality. The present review focuses on sources and risks of heavy metals, mainly in cultivated fields in various regions, and strategies to reduce their accumulation in horticultural crops. The following heavy metals are discussed: arsenic (As), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), mercury (Hg), molybdenum (Mo), nickel (Ni), strontium (Sr), tin (Sn), titanium (Ti), vanadium (V) and zinc (Zn). Heavy metal sources in the environment can originate from natural and anthropogenic activities. Their main natural enrichment in soils stems from parent-material weathering. However, in coastal areas, precipitation of sea spray may enrich soil with B. In contrast, the main anthropogenic sources of heavy metals in cultivated areas are irrigation with treated sewage water, application of residual biosolids, and atmospheric pollution. Plants absorb heavy metals predominantly through roots and, to a lesser extent, through leaves. Leaf uptake can occur through the stomata, cuticular cracks, ectodesmata, and aqueous pores. Heavy metal uptake may lead to their accumulation in vegetables and fruit trees, and their consequent introduction into the food chain, which is recognized as one of the major pathways for human exposure to them. This exposure can result in retardation, several types of cancer, kidney damage, endocrine disruption, and immunological and neurological effects. High concentrations of heavy metals can also affect the growth and yield of many crops: Zn and Cd decrease plant metabolic activity and induce oxidative damage; Cu generates oxidative stress and reactive oxygen species; Hg can induce visible injury and physiological disorders; Cr affects photosynthesis in terms of CO2 fixation, electron transport, photophosphorylation and enzyme activities; Pb induces plant abnormal morphology; Ni spoils the nutrient balance, resulting in disorders of cell membrane functions; Fe causes free radical production that irreversibly impairs cell structure and damages membranes, DNA and proteins; As causes leaf necrosis and wilting, followed by root discoloration and retardation of shoot growth. Therefore, international organizations, such as the US EPA and EU bodies, are working on regulating the maximum allowable levels of food pollutants. A number of direct (mycorrhiza, transgenic plants and grafting) approaches can be deployed to overcome problems of heavy metal contamination in horticulture.
M. Edelstein, and M. Ben-Hur,Heavy metals and metalloids: Sources, risks and strategies to reduce their accumulation in horticultural crops, Scientia Horticulturae, 2018, 234, 431-444.
EFFECT OF NANOAQUACITRATES ON PHYSIOLOGICAL PARAMETERS OF FODDER GALEGA INFECTED WITH PHYTOPLASMA
The laboratory experiments have been found that soaking seeds Galega orientalis L. (Fodder galega) in nanoaquacitrates solutions of Mn (10 and 20 mg/dm(3)), Mo (4 mg/dm(3)) and Mg (2 and 4 mg/dm(3)), has been lead to germination energy rise, while Mn (10 and 20 mg/dm(3)) and Mo (4 mg/dm(3)) concentrations has been influenced germinating ability. At the same time, the soaking seeds in solution of nanoaquacitrates Mn (20 mg/dm(3)) had the biggest stimulatory effect on the accumulation 7 daily sprouts mass (on 18%). It has been shown that soaking seeds in nanoparticles Mn and Mo solutions leads to the increase of catalase activities (especially under the influence of manganese) and peroxidase activities (under molybdenum influence). Applying the method of chlorophyll a fluorescence in the field and greenhouse experiments with Galega orientalis L. plants, artificial infected with phytoplasma Acholeplasma laidlawii var. granulum st. 118 the following changes in the photosynthetic apparatus has been indicated: reduction in the length of the light-antenna, blocking transport of electrons in plastoquinone pool PSII with reducing the pool of electron acceptors. It has also been indicated that photochemical activity resistance of the photosynthetic apparatus decreases while its stability increases, as result of described above effects the concentration of chlorophyll a and b in plants leaves decreases. The above-mentioned negative effects have been deactivated through foliar treatment of infected Galega orientalis L. plants with nanoaquacitrates solution Mo (4 mg/dm(3)) that allow increasing of photochemical resistance of photosynthetic apparatus as well as chlorophyll content in leaves. The foliar treatment with Mn (20 mg/dm(3)) solution of the infected plants, in compared with infected plants without treatment, resulted in more significant increase of Ki value (which correlate to the ribulose-1,5-bisphosphate carboxylase/oxygenase activity), which is explaining anti-mycoplasma effect of this solution.
H. Huliaieva, I. Tokovenko, V. Maksin, V. Kaplunenko, and A. Kalinichenko,EFFECT OF NANOAQUACITRATES ON PHYSIOLOGICAL PARAMETERS OF FODDER GALEGA INFECTED WITH PHYTOPLASMA, Ecological Chemistry and Engineering S-Chemia I Inzynieria Ekologiczna S, 2018, 25, 153-168.
Effect of food preparation using naturally-contaminated groundwater from La Pampa, Argentina: Estimation of elemental dietary intake from rice and drinking water
Water from La Pampa, Argentina, was used for washing and cooking rice to examine the in-situ impact of using naturally-contaminated water for food preparation on the elemental dietary intake. Whilst washing with the control tap water (28 mu g/L As) reduced the concentration of As in rice by 23%, the use of different well waters (281-1144 mu g/L) increased As levels significantly (8-227%) in comparison with the original concentration in the rice (0.056 mu g/g). Cooking the rice at a low water-to-rice ratio (2:1) using modern methods increased the levels of As in the cooked samples by 2-3 orders of magnitude for both pre-washed and un-washed rice. Similar trends were observed for vanadium. Although the levels of manganese, iron, copper, zinc and molybdenum in rice were reduced during washing and cooking for most water samples, the molybdenum concentration in the cooked rice doubled (2.2-2.9 mu g/g) when using water containing > 1 mg/L Mo.
M. Jaafar, A. L. Marcilla, M. Felipe-Sotelo, and N. I. Ward,Effect of food preparation using naturally-contaminated groundwater from La Pampa, Argentina: Estimation of elemental dietary intake from rice and drinking water, Food Chemistry, 2018, 246, 258-265.
Molybdenum isotope fractionation in plants measured by MC-ICPMS
A new method was developed for precise and accurate Mo isotope ratio measurements in plant materials by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). It is based on the use of anion-exchange chromatography to isolate Mo from concomitant matrix elements in sample digests, a desolvating Apex-Q sample inlet system as a means of Mo signal enhancement and on-line normalisation to an admixed internal standard (Pd) to correct for instrumental mass bias. Mo isotope ratios were determined in sample solutions with Mo concentrations as low as 10 ng g(-1). The developed method was successfully applied to the determination of natural variations in the isotopic composition of Mo in different anatomical parts of plants. We show for the first time that Mo isotope fractionation can occur during long-distance transport of Mo in plants. Our data also show that the magnitude of Mo isotope fractionation during translocation of Mo is different for different plant species. Mo isotope ratio data obtained by MC-ICPMS can therefore be used as a sensitive probe of processes controlling transport and distribution of molybdenum in plants.
D. Malinovsky, and N. A. Kashulin,Molybdenum isotope fractionation in plants measured by MC-ICPMS, Analytical Methods, 2018, 10, 131-137.
Subcellular distribution of molybdenum, ultrastructural and antioxidative responses in soybean seedlings under excess molybdenum stress
Some studies have shown that excess molybdenum (Mo) could produce toxic effects on plants. However, little is known about the subcellular distribution of Mo and cell ultrastructure within plants under excess Mo stress. Here, we comprehensively analyzed the changes of Mo distribution in subcellular fractions, cell ultrastructure and antioxidant enzymes in leaves and roots of soybean seedlings in response to excess Mo stress. The results showed that roots exhibited higher Mo accumulation than leaves at the 100 mg L(-1) Mo level, about 38.58-, 171.48- and 52.99-fold higher in cell walls, cell organelles and soluble fractions, respectively. Subcellular fractionations of Mo-containing tissues indicated that approximately 90% of Mo was accumulated in the soluble fractions and cell walls of the roots and leaves, and soluble fractions (accumulated 66.3-72.2% Mo) might serve as an effective storage site for excess Mo. Furthermore, excess Mo caused ultrastructural alterations in roots and leaves of soybean seedlings, leading to structural abnormality of chloroplast in leaf cells, plasmolysis, cellular deformity, vacuole enlargement and the swelling of cell wall and cytoplasm in root cells. Meanwhile, under excess Mo stress, the activity of POD, CAT and APX enzymes in roots was 1.43, 2.35 and 1.23 times that under standard Mo condition, while that of SOD and CAT enzymes in leaves was 1.23 and 1.94 times, respectively. This study provided novel insights into the mechanisms of excess Mo toxicity in soybean seedlings.
S. Xu, C. Hu, Q. Tan, S. Qin, and X. Sun,Subcellular distribution of molybdenum, ultrastructural and antioxidative responses in soybean seedlings under excess molybdenum stress, Plant physiology and biochemistry : PPB, 2017, 123, 75-80.
Potato tubers contamination with nitrate under the influence of nitrogen fertilizers and spray with molybdenum and salicylic acid
A field trial was conducted through 2015 and 2016 growing seasons to study the effect of nitrogen fertilizer sources and foliar spray with molybdenum (Mo), salicylic acid (SA) and their combination on tubers yield, some chemical constituents, nutrients uptake, nitrate accumulation and nitrate reductase activity in potato tubers. N source was added at a rate of 350 kg N ha(-1)in five equal doses as two different forms, the first is urea and the second is ammonium sulfate plus calcium nitrate equally. SA was sprayed with three rates of 0, 75 and 150 mg l(-1). Also, Mo as ammonium molybdate was sprayed using three rates 0, 50 and 100 mg l(-1)Mo. Both treatments of SA and Mo were applied separately as well as with each other, at three successive times 30, 50 and 70 days after planting of potato plants. Results indicated that the addition of 350 kg N ha(-1) as ammonium sulfate and calcium nitrate equally caused a significant elevation (P > 0.05) in fresh weight, chlorophyll b, carotenoids, chlorophyll a, nitrate reductase activity, dry weight and NPK uptake by potato tubers compared with the same amount of nitrogen in the form of urea only. All the aforementioned characteristics were improved with increasing concentration of Mo and/or SA. The highest accumulation of nitrate was recorded under the addition of 350 kg N ha(-1) as urea alone. The highest average of all the aforementioned characteristics was observed at the treatment of 350 kg N ha(-1) as ammonium sulfate and calcium nitrate equally plus spraying with 100 mg l(-1)Mo and 150 mg l(-1) SA. In contrast, this treatment gave the lowest accumulation of nitrates in potato tubers.
A. S. Elrys, A. I. E. Abdo, and E. M. Desoky,Potato tubers contamination with nitrate under the influence of nitrogen fertilizers and spray with molybdenum and salicylic acid, Environmental science and pollution research international, 2018, 25, 7076–7089.
Gene expression related to molybdenum enzyme biosynthesis in response to molybdenum deficiency in winter wheat
Molybdenum (Mo) is an essential trace element for higher plants. Mo enzyme biosynthesis is regulated by several plant genes. A hydroponic trial was conducted to investigate the effect of Mo deficiency on the expression of genes that are related to Mo enzyme biosynthesis in winter wheat. The results showed that Mo deficiency decreased the activities of nitrate reductase (NR), sulphite oxidase (SO), aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) in the leaves or roots of winter wheat by regulating the expression of NR, SO, AO and XDH genes. Mo deficiency induced the expression of TaCnx2 and TaCnx5, which might result in the accumulation of cyclic pyranopterin monophosphate (cPMP) and molybdopterin (MPT) in wheat. Mo deficiency significantly decreased TaCnx1 expression, which is expected to reduce molybdenum cofactor (Moco) formation. Moco shortage induced the expression of TaAba3 in winter wheat. The blockade of Moco biosynthesis under conditions of Mo deficiency might decrease the activities of Mo enzymes.
Nie, Z. J., Hu, C. X., Tan, Q. L., and Sun, X. C.,Gene expression related to molybdenum enzyme biosynthesis in response to molybdenum deficiency in winter wheat, Journal of Soil Science and Plant Nutrition, 2016, 16, 979-990.
Effect of molybdenum levels on photosynthetic characteristics, yield and seed quality of two oilseed rape (Brassica napus L.) cultivars
Molybdenum (Mo) is an essential element for higher plants. The objective of this study is to evaluate the effect of different Mo levels on the photosynthetic characteristics, yield and seed quality of two oilseed rape cultivars (ZS11 and L0917) using a pot experiment at four Mo levels [0 (control), 0.15, 0.3 and 1.0mgkg-1]. Results showed that the dry matter significantly increased with Mo concentration increasing at the stem elongation stage. The net photosynthesis rate (P-n), stomatal conductance (G(s)) and transpiration rate (T-r) were the highest at the 0.15mgkg-1 level but reduced at 0.3 and 1.0mgkg-1 levels. The yield and harvest index were highest at 0.15 and 0.3mgkg-1 for ZS11 and L0917, respectively. Gray correlation model analysis showed that the synthetic characteristics of seed quality (expressed as gray relation degree) followed the sequence of Mo1.0 > Mo 0 > Mo 0.3 > Mo 0.15mgkg-1 for L0917 and Mo 1.0 > Mo 0.15 > Mo 0 > Mo 0.3mgkg-1 for ZS11. Our results demonstrate that the yield of oilseed rape reached a maximum at 0.15 and 0.30mgkg-1 for ZS11 and L0917, respectively, while the integrated seed quality is optimal at 1.0mgkg-1 for both cultivars in Mo-deficient soil.
Qin, S. Y., Hu, C. X., Tan, Q. L., and Sun, X. C.,Effect of molybdenum levels on photosynthetic characteristics, yield and seed quality of two oilseed rape (Brassica napus L.) cultivars, Soil Science and Plant Nutrition, 2017, 63, 137-144.
Cucumber molybdenum and iron
Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants
Molybdenum (Mo) and iron (Fe) are essential micronutrients required for crucial enzyme activities in plant metabolism. Here we investigated the existence of a mutual control of Mo and Fe homeostasis in cucumber (Cucumis sativus).
Plants were grown under single or combined Mo and Fe starvation. Physiological parameters were measured, the ionomes of tissues and the ionomes and proteomes of root mitochondria were profiled, and the activities of molybdo-enzymes and the synthesis of molybdenum cofactor (Moco) were evaluated.
Fe and Mo were found to affect each other's total uptake and distribution within tissues and at the mitochondrial level, with Fe nutritional status dominating over Mo homeostasis and affecting Mo availability for molybdo-enzymes in the form of Moco.
Fe starvation triggered Moco biosynthesis and affected the molybdo-enzymes, with its main impact on nitrate reductase and xanthine dehydrogenase, both being involved in nitrogen assimilation and mobilization, and on the mitochondrial amidoxime reducing component.
These results, together with the identification of > 100 proteins differentially expressed in root mitochondria, highlight the central role of mitochondria in the coordination of Fe and Mo homeostasis and allow us to propose the first model of the molecular interactions connecting Mo and Fe homeostasis.
Vigani, G., Di Silvestre, D., Agresta, A. M., Donnini, S., Mauri, P., Gehl, C., Bittner, F., and Murgia, I.,Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants, The New phytologist, 2017, 213, 1222-1241
Effects of tungsten on uptake, transport and subcellular distribution of molybdenum in oilseed rape at two different molybdenum levels
Due to the similarities of molybdenum (Mo) with tungsten (W) in the physical structure and chemical properties, studies involving the two elements have mainly examined their competitive relationships. The objectives of this study were to assess the effects of equimolar W on Mo accumulation, transport and subcellular distribution in oilseed rape at two Mo levels with four treatments: Mo1 (1mumol/L Mo, Low Mo), Mo1+W1 (1mumol/L Mo+1mumol/LW, Low Mo with Low W), Mo200 (200mumol/L Mo, High Mo) and Mo200+W200 (200mumol/L Mo+200mumol/L Mo, High Mo with high W). The fresh weight and root growth were inhibited by equimolar W at both low and high Mo levels. The Mo concentration and accumulation in root was increased by equimolar W at the low Mo level, but that in the root and shoot was decreased at the high Mo level. Additionally, equimolar W increased the Mo concentrations of xylem and phloem sap at low Mo level, but decreased that of xylem and increased that of phloem sap at the high Mo level. Furthermore, equimolar W decreased the expression of BnMOT1 in roots and leaves at the low Mo level, and only decreased its expression in leaves at the high Mo level. The expression of BnMOT2 was also decreased in root for equimolar W compared with the low Mo level, but increased compared with high Mo level. Moreover, equimolar W increased the proportion of Mo in cell wall fraction in root and that of soluble fraction in leaves when compared with the low Mo level. The results suggest that cell wall and soluble fractions might be responsible for the adaptation of oilseed rape to W stress.
Qin, S., Sun, X., Hu, C., Tan, Q., Zhao, X., and Xu, S.,Effects of tungsten on uptake, transport and subcellular distribution of molybdenum in oilseed rape at two different molybdenum levels, Plant science : an international journal of experimental plant biology, 2017, 256, 87-93.
Molybdenum Stress Modulates Enzymes Responsive to Oxidative Stress and Affects Seeds Viability and Vigor in Chickpea
The importance of molybdenum (Mo) for plant growth is disproportionate with respect to the absolute amounts required by most plants. Chickpea (Cicer arietinum L.) cv. K-75 plants were raised in refined sand in glasshouse at graded levels from 0.002 to 1 mu M for 100days. Mo deficiency symptoms appeared as interveinal chlorosis of middle and old leaves. Compared with the control (0.2 mu M Mo), dry matter, yield and seed protein decreased at low and excess Mo. The concentration of Mo in leaves and seed as well as the activity of nitrate reductase (NR) increased with an increase in Mo supply. The activities of antioxidative enzymes stimulate at both low and excess Mo supply. Low and excess Mo decreased the lipid peroxidation status in chickpea leaves, suggesting its antiperoxidative nature. The values of deficiency, threshold of deficiency and threshold of toxicity of Mo were, respectively, 0.38, 1.2 and 15 mu g g(-1) in leaves of chickpea.
Gopal, R., and Shukla, A. K.,Molybdenum Stress Modulates Enzymes Responsive to Oxidative Stress and Affects Seeds Viability and Vigor in Chickpea, Communications in Soil Science and Plant Analysis, 2017, 48, 43-50.
Metals Content in HERBAL SUPPLEMENTS
Obesity has become an international epidemic. To evaluate the level of metals in extracts of plants prescribed as weight loss supplements, different brands containing Camellia sinensis (L.) Kuntze, Citrus aurantium L., Cordia ecalyculata Vell, Ilex paraguariensis A. St.-Hil, Cissus quadrangularis L., Senna alexandrina Mill were purchased in local market, hot acid digested, and analyzed while metal content by inductively coupled plasma optical emission spectrometry, ICP-OES. Quality assurance and quality control tests were carried out in order to monitor and control the reliability of the analytical method. For each metal evaluated, a calibration curve was prepared with certified reference material. The recovery test was performed for each batch of samples. Analyses were performed in triplicate. Quantification of aluminum, barium, cadmium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, lead, vanadium, and zinc were determined. The metals most frequently detected were manganese (15.3-329,60 mg kg-1) aluminum (11.76-342.4 mg kg-1), and iron (11.14-73.01 mg kg-1) with higher levels in products containing C. sinensis China origin, I. paraguariensis Brazilian origin, C. quadrangularis, and C. aurantium China origin, respectively. To ensure safety consumption, an adequacy of the certification of Brazilian suppliers for herbal weight loss products is indispensable.
Barrella, M. V., Heringer, O. A., Cardoso, P. M., Pimentel, E. F., Scherer, R., Lenz, D., and Endringer, D. C.,Metals Content in Herbal Supplements, Biological trace element research, 2017, 175, 488-494.
Molybdenum and iron mutually impact their homeostasis in CUCUMBER (Cucumis sativus) plants
Molybdenum (Mo) and iron (Fe) are essential micronutrients required for crucial enzyme activities in plant metabolism. Here we investigated the existence of a mutual control of Mo and Fe homeostasis in cucumber (Cucumis sativus). Plants were grown under single or combined Mo and Fe starvation. Physiological parameters were measured, the ionomes of tissues and the ionomes and proteomes of root mitochondria were profiled, and the activities of molybdo-enzymes and the synthesis of molybdenum cofactor (Moco) were evaluated. Fe and Mo were found to affect each other's total uptake and distribution within tissues and at the mitochondrial level, with Fe nutritional status dominating over Mo homeostasis and affecting Mo availability for molybdo-enzymes in the form of Moco. Fe starvation triggered Moco biosynthesis and affected the molybdo-enzymes, with its main impact on nitrate reductase and xanthine dehydrogenase, both being involved in nitrogen assimilation and mobilization, and on the mitochondrial amidoxime reducing component. These results, together with the identification of > 100 proteins differentially expressed in root mitochondria, highlight the central role of mitochondria in the coordination of Fe and Mo homeostasis and allow us to propose the first model of the molecular interactions connecting Mo and Fe homeostasis.
Vigani, G., Di Silvestre, D., Agresta, A. M., Donnini, S., Mauri, P., Gehl, C., Bittner, F., and Murgia, I.,Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants, The New phytologist, 2017, 213, 1222-1241.
Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of ALFALFA
Rhizobia-legume symbiosis is the most well researched biological nitrogen fixation system. Coating legume seeds with rhizobia is now a recognized practical measure for improving the production of legume corp. However, the efficacy of some commercial rhizobia inoculants cannot be guaranteed in China due to the low rate of live rhizobia in these products. A greenhouse experiment was conducted to assess the effects of different rhizobial inoculant formulations on alfalfa productivity and nitrogen fixation. Two rhizobia strains, (ACCC17631 and ACCC17676), that are effective partners with alfalfa variety Zhongmu No. 1 were assessed with different concentrations of ammonium molybdate in seed-coat formulations with two different coating adhesives. Our study showed that the growth, nodulation, and nitrogen fixation ability of the plants inoculated with the ACCC17631 rhizobial strain were greatest when the ammonium molybdate application was0.2% of the formulation. An ammonium molybdate concentration of 0.1% was most beneficial to the growth of the plants inoculated with the ACCC17676 rhizobial strain. The sodium carboxymethyl cellulose and sodium alginate, used as coating adhesives, did not have a significant effect on alfalfa biomass and nitrogen fixation. However, the addition of skimmed milk to the adhesive improved nitrogenase activity. These results demonstrate that a new rhizobial seed-coat formulation benefitted alfalfa nodulation and yield.
Zhou, J., Deng, B., Zhang, Y., Cobb, A. B., and Zhang, Z.,Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of Alfalfa, PLoS One, 2017, 12, e0170179.
Nutrient deficiencies in Brassica napus modify the ionomic composition of plant tissues: a focus on cross-talk between molybdenum and other nutrients
The composition of the ionome is closely linked to a plant's nutritional status. Under certain deficiencies, cross-talk induces unavoidable accumulation of some nutrients, which upsets the balance and modifies the ionomic composition of plant tissues. Rapeseed plants (Brassica napus L.) grown under controlled conditions were subject to individual nutrient deficiencies (N, K, P, Ca, S, Mg, Fe, Cu, Zn, Mn, Mo, or B) and analyzed by inductively high-resolution coupled plasma mass spectrometry to determine the impact of deprivation on the plant ionome. Eighteen situations of increased uptake under mineral nutrient deficiency were identified, some of which have already been described (K and Na, S and Mo, Fe, Zn and Cu). Additionally, as Mo uptake was strongly increased under S, Fe, Cu, Zn, Mn, or B deprivation, the mechanisms underlying the accumulation of Mo in these deficient plants were investigated. The results suggest that it could be the consequence of multiple metabolic disturbances, namely: (i) a direct disturbance of Mo metabolism leading to an up-regulation of Mo transporters such as MOT1, as found under Zn or Cu deficiency, which are nutrients required for synthesis of the Mo cofactor; and (ii) a disturbance of S metabolism leading to an up-regulation of root SO4 2- transporters, causing an indirect increase in the uptake of Mo in S, Fe, Mn, and B deficient plants.
Maillard, A., Etienne, P., Diquelou, S., Trouverie, J., Billard, V., Yvin, J. C., and Ourry, A.,Nutrient deficiencies in Brassica napus modify the ionomic composition of plant tissues: a focus on cross-talk between molybdenum and other nutrients, Journal of experimental botany, 2016.
Molybdenum FERTILIZATION effect on nodulation, yield and quality of green gram grown in the soils of southern agro-climatic zone of Tamil Nadu, India
A pot experiment was conducted under natural condition with green gram (cultivar CO 6) using twenty bulk soil samples collected from major soil series of Southern agro climatic zone of Tamil Nadu.
Application of graded levels of molybdenum (Mo) at 0, 0.025, 0.050, 0.075 and 0.1 mg kg-1 positively influenced the yield, nodulation characteristics and nutritional quality of green gram crop. The highest number of nodules, dry weight nodules per plant, nodule N concentration and chlorophyll content of leaves were registered at 0.075 mg kg-1 level.
Similarly, the seed and stover yield, uptake of N, P, K and Mo by green gram were also increased with molybdenum application up to 0.075 mg kg-1 level beyond which they declined.
However, the amount of protein in seed significantly increased with increasing levels of Mo up to 0.1 mg kg-1 level in different soils.
Hence, Mo application not only increased the yield but also enhanced the nutritional quality of green gram through effective nodulation.
Velmurugan, R., and Mahendran, P. P.,Molybdenum fertilization effect on nodulation, yield and quality of green gram grown in the soils of southern agro-climatic zone of Tamil Nadu, India, Legume Research, 2015, 38, 798-803.
[Green gram, also known as the mung bean, is a small round bean similar in shape to the field pea. People in the U.S. primarily eat green gram as a sprout, and as a bean it cooks up fast and has a sweet flavor. With its high fiber and nutrient content, it offers a number of health benefits. www.livestrong.com.]
Molybdate effect of molybdenum on nodulation, plant yield and nitrogen uptake in hairy vetch (Vicia villosa Roth)
Hairy vetch (Vicia villosa Roth) is a leguminous cover crop that is generally used as a green manure to sustain soil health in arable land. Molybdenum (Mo) acts as a cofactor for the nitrogenase (NA) and nitrate reductase (NR) enzymes, which are important for nitrogen (N) fixation, nitrate reduction and N transport in plants. In this study, we applied various doses of Mo to soil to evaluate their efficacy on nodulation, nodule characteristics and biomass production of hairy vetch. Mo application increased the number and size of nodules and NA and NR enzyme activity in hairy vetch. This increase in enzyme activity increased N assimilation and led to higher biomass yield. Plants grown in soil that received 0.5mg Mo kg-1 showed optimal physical and biochemical properties in nodules, and these properties may explain the increased N fixation in hairy vetch. Higher Mo doses (1.0 mg kg-1) led to the deterioration of nodule structure and, hence, reduced enzymatic activity in plants. The 16S rRNA gene sequencing and cluster analysis showed that the bacterial isolates found in the nodules of hairy vetch roots belonged to the Rhizobiaceae family and shared high sequence similarity with Rhizobium leguminosarum and Agrobacterium tumefaciens. Application of 0.63mg Mo kg-1 to soil was the optimum dose to maximize the biomass yield of hairy vetch.
Alam, F., Kim, T. Y., Kim, S. Y., Alam, S. S., Pramanik, P., Kim, P. J., and Lee, Y. B.,Effect of molybdenum on nodulation, plant yield and nitrogen uptake in hairy vetch (Vicia villosa Roth), Soil Science and Plant Nutrition, 2015, 61, 664-675.
MOLYBDATE PLANTS SOYBEAN SEED COATING
In Japan, soybeans are generally cultivated in paddy fields which often have poor drainage. West of the Kanto region, the seeds are sown in the rainy season. Therefore, the seedling establishment is prone to damage by the rain after sowing. The generation of sulfide ions in flooded and reduced soil is thought to be one factor causing this flooding damage. Since molybdate ions suppress the generation of sulfide ions, the effect of coating soybean seeds with molybdenum compounds, on the seedling establishment under a flooded condition was examined. Soybean seeds were coated with several kinds of poorly-soluble molybdenum compounds at different concentrations. The coated seeds were sown in soil and then flooded for 3 d at 25 - 30 degrees C. Seedlings were not established from seeds not coated with molybdenum compounds. Seedling establishment was appreciably improved by coating the seeds with a molybdenum compound at the rate of 0.5 - 1 mol-Mo kg(-1) seed. Seedling establishment was especially improved by coating with molybdenum trioxide. Accordingly, coating the soybean seed with molybdenum compounds could mitigate the flooding damage occurring after sowing.
Hara, Y.,Improvement of Soybean Seedling Establishment under a Flooded Condition by Seed Coating with Molybdenum Compounds, Plant Production Science, 2015, 18, 161.
MOLYBDATE (?) PLANTS DRY BEAN MOLYBDENUM REQUIREMENTS NO LIMING
Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20mgkg(-1). In one experiment dolomitic lime was added at the rate of 2.5g per kg of soil before the application of Mo treatments and incubated 5weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20mgkg(-1). Maximum shoot dry weight was obtained with the addition of 17mgMokg(-1) in the experiment with Mo rates without lime and 9.69mgMokg(-1) in the experiment of Mo rates with lime application. Maximum seed yield was obtained with the application of 10.48mgMokg(-1) in the experiment that did not receive lime along with Mo treatments and 10.28mgMokg(-1) in the experiment that received lime along with Mo treatments. Similarly, the maximum number of pods per plant was obtained with the addition of 9.33mgMokg(-1) in the experiment that did not receive lime and 8.83mgMokg(-1) in the experiment that did receive lime. Maximum root length was obtained with the addition of 12.38Mokg(-1) in the experiment that did not receive lime and 9.75mgMokg(-1) in the experiment that received lime. Maximum root dry weight was obtained with the addition of 11.67mgMokg(-1) in the experiment that did not receive lime and 9.28mgMo in the experiment that received lime. Soil properties determined after harvest of dry bean plants were not influenced significantly with the addition of Mo in the Oxisol under investigation.
Fageria, N. K., Stone, L. F., and Santos, A. B.,Molybdenum Requirements of Dry Bean with and without Liming, Communications in Soil Science and Plant Analysis, 2015, 46, 965.
MOLYBDATE (?) PLANTS RED BASIL
Red basil (Ocimum basilicum L.) cv. Red Rubin was cultivated in model pot experiment in the soil amended by arsenic, cadmium and lead solutions in stepwise concentrations representing the soil concentration levels of former mining area in the vicinity of Pribram, Czech Republic. The element levels added to the soil reached up to 40 mg Cd, 100 mg As, and 2000 mg Pb per kg of soil. Moreover, essential macro-and microelements as well as cyanidine contents were investigated to assess their potential interactions with the risk elements. The extractable element portions in soils determined at the end of vegetation period differed according to the individual elements. Whereas the plant-available (extractable with 0.11M CH3COOH) content of Cd represented 70-100% of the added Cd, the mobile portion of Pb did not exceed 1%. The risk element content in plants reflected the increasing element contents in soil. The dominant element portions remained in plant roots indicating the limited translocation ability of risk elements to the aboveground biomass of this plant species. Although the risk element contents in amended plants significantly increased, no visible symptoms of phytotoxicity occurred. However, the effect of enhanced risk element contents on the essential element uptake was assessed. Considering inter-element relationships, elevated sulphur levels were seen in amended plants, indicating its possible role of phytochelatin synthesis in the plants. Moreover, the molybdenum contents in plant biomass dropped down with increasing risk element uptake by plants confirming As-Mo and Cd-Mo antagonism. The increasing content of cyanidine in the plant biomass confirmed possible role of anthocyanins in detoxification mechanism of risk element contaminated plants and suggested the importance of anthocyanin pigments for risk element tolerance of plants growing in contaminated areas.
Ruzickova, P., Szakova, J., Havlik, J., and Tlustos, P.,The effect of soil risk element contamination level on the element contents in Ocimum basilicum L, Archives of Environmental Protection, 2015, 41, 47.