Effect of molybdenum treatment on molybdenum concentration and nitrate reduction in maize seedlings

Abstract

Since 1940 molybdenum has been known as an essential trace element in plant nutrition and physiology. It has a central role in nitrogen metabolism, and its deficiency leads to nitrate accumulation in plants. In this study, we cultivated maize seedlings (Zea mays L. cv. Norma SC) in nutrient solution and soil (rhizoboxes) to investigate the effect of molybdenum treatment on the absorption of molybdenum, sulphur and iron. These elements have been previously shown to play important roles in nitrate reduction, because they are necessary for the function of the nitrate reductase enzyme. We also investigated the relationship between molybdenum treatments and different nitrogen forms in maize. Molybdenum treatments were 0, 0.96, 9.6 and 96 μg kg-1 in the nutrition solution experiments, and 0, 30, 90, 270 mg kg-1 in the rhizobox experiments. On the basis of our results, the increased Mo level produced higher plant available Mo concentration in nutrient solution and in soil, which resulted increased concentration of Mo in shoots and roots of maize seedlings. In addition it was observed that maize seedlings accumulated more molybdenum in their roots than in their shoots at all treatments. In contrast, molybdenum treatments did not affect significantly either iron or sulphur concentrations in the plant, even if these elements (Mo, S and Fe) play alike important roles in nitrogen metabolism. Furthermore, the physiological molybdenum level (1x Mo = 0.01 µM) reduced NO3-N and enhanced the NH4-N concentrations in seedlings, suggesting that nitrate reduction was more intense under a well-balanced molybdenum supply.

Arbuscular Mycorrhizal Fungi Improve the Performance of Sweet Sorghum Grown in a Mo-Contaminated Soil

“…Generally, plant Mo concentrations are correlated positively with Mo levels in the plant growth substrate [42,43]. In our experiment, root Mo concentrations and shoot Mo concentrations in mycorrhizal plants showed positive correlations with soil Mo concentrations ( Table 2).…”

Arbuscular mycorrhizal inoculation increases molybdenum accumulation but decreases molybdenum toxicity in maize plants grown in polluted soil

“…Excess Mo causes toxic effects in plants, such as alteration of morphology, cell structures and physiological responses. 27,28 However, the toxicity threshold values of Mo greatly varied with soil properties and plant species, with a wide range of added Mo concentrations generating 50% inhibition of plant growth (ED 50 ) among the surveyed 10 soils, ranging from less than 1 mg kg À1 to higher than several thousand mg kg À1 , and ryegrass showed higher resistance to Mo toxicity than other three crops (oilseed rape, red clover, and tomato). 29 In the present study, the added Mo caused plant growth reduction in most cases, suggesting a phytotoxic effect on maize grown in the studied soil.…”

Agronomic biofortification with selenium impacts storage proteins in grains of upland rice

“…In our former study, Reis et al observed the interaction between nitrogen and Se in upland rice under field conditions showing that plants treated with nitrogen can accumulate more Se in seeds. In addition, Se can affect sulfur metabolism and molybdenum concentration in plants, which is co‐factor of nitrate reductase enzyme showing a direct effect on nitrogen metabolism ,,35–37…”

“…In addition, Se can affect sulfur metabolism and molybdenum concentration in plants, which is co-factor of nitrate reductase enzyme showing a direct effect on nitrogen metabolism. 23,28,[35][36][37] The application of Se along with nitrogen, phosphorus and potassium (NPK) fertilizer is an effective way to address the low concentrations of Se typically found in human and animal food, as demonstrated by the results of decades of study in Finland. [24][25][26] After the adoption of the Se biofortification programme in Finland, the Se status of the population has improved to optimal levels.…”