Mn In Nutrient Solution Research Articles

Interaction of silicon and manganese in nutritional and physiological aspects of energy cane with high fiber content

BackgroundSilicon (Si) is a multiple stress attenuator element in plants, however more research is needed to elucidate the actions in the plants defense system with low nutrition of manganese (Mn) for a prolonged period, and the attenuation mechanisms involved in the effects of Mn deficiency on energy cane with high fiber content. Thus, the objective of this study was to evaluate whether Si reduces the oxidative stress of the energy cane grown in low Mn in nutrient solution, to mitigate the effects of Mn deficiency, improving enzymatic and non-enzymatic defense, uptake of Mn the plant growth.MethodsAn experiment was carried out with pre-sprouted seedlings of Saccharum spontaneum L. in a 2 × 2 factorial scheme in five replications in which the plants were grown under sufficiency (20.5 μmol L−1) and deficiency (0.1 μmol L−1) of Mn combined with the absence and presence of Si (2.0 mmol L−1) for 160 days from the application of the treatments. The following parameters were evaluated: accumulation of Mn and Si, H2O2, MDA, activity of SOD and GPOX, total phenol content, pigments, and quantum efficiency of PSII.ResultsMn deficiency induced the oxidative stress for increase the H2O2 and MDA content in leaves of plants and reduce the activity of antioxidant enzymes and total phenols causing damage to quantum efficiency of photosystem II and pigment content. Si attenuated the effects of Mn deficiency even for a longer period of stress by reducing H2O2 (18%) and MDA (32%) content, and increased the Mn uptake efficiency (53%), SOD activity (23%), GPOX (76%), phenol contents, thus improving growth.ConclusionsThe supply of Si promoted great nutritional and physiological improvements in energy cane with high fiber content in Mn deficiency. The results of this study propose the supply of Si via fertirrigation as a new sustainable strategy for energy cane cultivation in low Mn environments.

Time-resolved X-ray fluorescence analysis of element distribution and concentration in living plants: An example using manganese toxicity in cowpea leaves

The distribution and concentration of nutrients and contaminants affect almost every metabolic process in plants but analytical limitations have hindered the determination of microscopic changes over time within living plant tissues. We developed a novel method using synchrotron-based micro X-ray fluorescence (μ-XRF) that, for the first time, allows quantification of the spatial and temporal changes of multiple elements in the same area of living leaves. The utility of this approach was tested by examining changes over 48 h in unifoliate leaves of 7-d-old cowpea (Vigna unguiculata) plants simultaneously at 0.2 and 30 μM Mn in nutrient solution, with 30 μM Mn known to be toxic to cowpea and cause the formation of Mn-dense lesions. The fast X-ray fluorescence detector system reduced dwell on living leaf samples. This produced no evidence of tissue damage through repeated μ-XRF scanning, thereby overcoming previously noted experimental artifacts. This permitted, for the first time, visual and quantitative assessments of spatial and temporal changes in nutrient concentrations. By focusing on changes in Mn status, this study illustrated extension of two-dimensional μ-XRF scans to a three-dimensional geometry of Mn kinetics in the same area of leaves. The multi-element potential of this method was exemplified through the measurement of distributions and concentrations of K, Ca, Fe, Cu, and Zn within living plant leaves. This novel method and accompanying information on changes in Mn distribution showed the potential for microscopic, time-resolved, in vivo examination of changes in elemental distribution. We consider that this method will be of benefit for a wide range of studies, including functional characterization of molecular biology, examining changes in the distribution of nutrients, and understanding the movement and toxicity of contaminants.

Physiological, biochemical and molecular responses of Mentha aquatica L. to manganese

Mentha aquatica is an aromatic herb which possesses valuable terpenoids constituents. Here, we intended to evaluate the effects of the different manganese (Mn) concentrations on the physiological, biochemical and molecular responses in M. aquatica. Basic Hoagland's solution (control), 40, 80, and 160 μM of Mn supplied as MnSO4·H2O were applied to the nutrient solution. The results indicated that the different concentrations of Mn differently affected the physiological, biochemical and molecular responses in M. aquatica. The growth parameters (biomass and photosynthetic pigments) and expression levels of β-caryophyllene synthase (CPS), limonene synthase (Ls), geranyl diphosphate synthase (Gpps), and menthofuran synthase (Mfs) genes were increased at the moderate Mn concentrations (40 and 80 μM) and began to decrease at the higher levels. However, the contents of anthocyanins, flavonoids, malonaldehyde (MDA) and hydrogen peroxide (H2O2), Mn accumulation, activities of antioxidant enzymes, yield of essential oils and the expression levels of 1-Deoxy d-xylulose-5-phosphate synthase (Dxs) and isopentenyl diphosphate isomerase (Ippi) genes were gradually increased with increasing concentration of Mn in the nutrient solution. Also, the content and chemical composition of terpenoid constituents were altered in the Mn-treated plants. Here, we suggest that the application of external Mn in nutrient solution elevates the growth and expression levels of the genes that are involved in the terpenoid biosynthesis pathway in M. aquatica. Nevertheless, the extent and stability of these growth and gene expression elevation are varied among the different Mn treatments.

Interaction Effects of Zinc and Manganese on Growth, Uptake Response and Chlorophyll Content of Sweet Corn (Zea mays var. saccharata)

Manganese (Mn) and Zinc (Zn) interact with each other and this interaction can result in impacts on the yield of corn plants. This study was conducted to examine the effect of different levels of Mn and Zn on the yield, Mn and Zn concentration, root growth parameters and chlorophyll contents of corn plants. Sweet corn was grown in nutrient culture containing all combinations of Zn and Mn at levels of 0.0, 0.1, 1.0 and 10.0 mg L-1 as ZnSO4.7H2O and MnSO4.H2O, respectively and harvested at 28 days after transplanting. Mn and Zn concentrations in roots and shoots increased with increasing Mn and Zn concentration in nutrient solution. Zn concentration in both roots and shoots enhanced with increasing Mn levels. Mn concentration in shoots did not show any correlation with Zn concentration in nutrient solution, but Mn concentration in roots decreased with increasing levels of Zn. Zn0Mn1 treatment produced the highest yield. The lowest dry weight of young corn plants was recorded under Zn10Mn0 treatment due to Mn deficiency. Chlorophyll content decreased with high Zn application and this can be attributed to the interaction of Zn with iron in the growth medium. Different levels of Zn and Mn in nutrient solution did not have any significant effect on root parameters.

MANGANESE TOXICITY IN THREE SPECIES OF ANNUAL MEDICS

The selection of Medicago spp. cultivars tolerant to high levels of manganese (Mn) is needed if they are to be established in acidic soils. We compared the growth of three species of annual medics (M. polymorpha, M. murex and M. tornata) in an acid soil with a high level of extractable Mn, and in nutrient solutions with 100 and 500 μM Mn. M. polymorpha accumulated the greatest biomass in the field, in pots, and in nutrient solution, but M. murex was the most tolerant of a high level of Mn in nutrient solution and in the unlimed acid soil in pots. M. tornata produced a similar biomass to M. murex in limed soil and in a nutrient solution with a low level of Mn. However, it was very sensitive to a high level of Mn, both in solution and in unlimed soil. The relative growth between the three species in the field, in pots, and in nutrient solution was comparable, suggesting that selection in nutrient solution can be used to identify ecotypes tolerant to Mn.

CHARACTERIZATION OF MANGANESE TOXICITY IN TWO SPECIES OF ANNUAL MEDICS

There is interest in the development of cultivars of Medicago spp. tolerant to soil acidity, where manganese (Mn) can be a major constraint to plant growth. We evaluated the response of several ecotypes of M. polymorpha and M. murex to a high level of Mn (50 mg Mn kg−1 soil), and its impact on biological N2 fixation and mineral composition. Plant growth in pots was decreased by Mn toxicity, whether plants were dependent on N2 fixation or provided with fertilizer nitrogen (N). Plant growth was impaired by high levels of Mn to a greater extent than was N2 fixation. Tolerance to high levels of Mn differed between the ecotypes, with accession 66 of M. polymorpha and 194 of M. murex being the most tolerant. A 500 μM concentration of Mn in nutrient solution led to decreased concentration of zinc (Zn) in the whole plant, and to modifications in the partition of iron (Fe), potassium (K), and calcium (Ca) between roots and shoots. Tolerance to Mn was negatively correlated with the concentrations of Mn and Zn in the roots.

Mechanism of manganese toxictty and tolerance of plants VII. effect of light intensity on manganese‐induced chlorosis

Abstract Effect of light intensity on Mn‐induced chlorosiss was investigated with bush bean (Phaseolus vulgaris L.) and corn (Zea mays L.) seedlings. The seedlings were grown in nutrient solutions containing different concentrations of Mn in enclosures which transmitted different percentages of the total solar radiation. At high levels of Mn in nutrient solution, the increase in light intensity increased the Mn uptake by the plant and resulted in a decrease in the chlorophyll content of the leaves. Even at similar levels of Mn concentrations within the leaves, high light intensity increased the severity of Mn‐induced chlorosis. Photobleaching experiments were carried out with isolated chloroplasts suspended in media containing 0, 10‐4 , 10‐3,10‐2 and 10‐1 M Mn2+. Addition of Mn2+ to the medium decreased the extent of photobleacing of chlorophyll with increaing Mn2+ concentration up to 10‐3 M . In concentrations of Mn2+ higher than 10‐3 M, the extent of bleaching was increased again, accompanied by precipi...

Differential tolerance of bush bean cultivars to excess manganese in solution and sand culture

Abstract Nineteen bush bean cultivars were screened for tolerance to excess Mn in nutrient solution and sand culture experiments. Seven‐day‐old seedlings were treated with full strength Hoagland No. 2 nutrient solution containing different Mn concentrations for 12 days in the greenhouse. Cultivars showing the greatest sensitivity to Mn toxicity were ‘Wonder Crop 1’ and ‘Wonder Crop 2'; those showing the greatest tolerance were ‘Green Lord’, ‘Red Kidney’ and ‘Edogawa Black Seeded’. Leaf Mn concentration of plants grown in sand culture was higher than that for plants grown in solution culture. The lowest leaf Mn concentration at which Mn toxicity symptoms developed, was higher in tolerant than in sensitive cultivars. The Fe/Mn ratio in the leaves at which Mn toxicity symptoms developed, was higher in the sensitive cultivars than in the tolerant ones. We concluded that Mn tolerance in certain bush bean cultivars is due to a greater ability to tolerate a high level of Mn accumulation in the leaves.

THE INFLUENCE OF NITROGEN SOURCE ON THE TOLERANCE OF HOLCUS LANATUS L.* AND BROMUS ERECTUS HUDS. TO MANGANESE

SUMMARYBoth Bromus erectus and Holcus lanatus grew better in NO3‐N than in NH4‐N. NH4‐N inhibited Mn uptake and NO3‐N enhanced it. The concentration of Mn found in both species was greater in NO3‐N than NH4‐N treated plants and increased severity of toxicity symptoms was observed in plants given NO3‐N treatments. In general, uptake and concentration of Mn was greater in Holcus than in Bromus, although Holcus displayed less severe symptoms of toxicity. Root concentrations of Mn were greater than those of shoots in Holcus. As excess Mn generally affects plant tops more severely than roots it is possible that a mechanism reducing upward translocation of Mn conferred a degree of tolerance in Holcus. Growth of the population of Holcus used was affected to a lesser extent than Bromus by large concentrations of Mn in nutrient solution which may partially account for the markedly different frequency of occurrence of these species on soils which contain high concentrations of both NH4‐N and Mn. In Bromus NH4‐N and Mn interact to reduce their combined effects but in both species the adverse effects of NH4‐N on growth for the most part masks that of Mn. Conversely with NO3‐N, itself beneficial, Mn uptake is not depressed as it is with NH4‐N and when Mn‐toxicity occurs, it is more marked. In solution culture Bromus is very sensitive to NH4‐N and also to Mn in the presence of NH4‐N or NO3‐N, whereas in the kind of habitat in which Bromus occurs N is present as NO3 and the adverse effect of any Mn present is neutralized by Ca.

Effect of Temperature on Soybean Growth and Manganese Accumulation1

AbstractManganese deficiency in soybeans (Glycine max (L.) Merr.) appears to be more severe in spring than in summer. This may result from a decrease in the Mn supply relative to growth or an increase in the functional requirement of Mn under cooler conditions. To examine the supply‐functional concentration relationship, experiments were conducted in growth chambers at various temperatures. Manganese deficient soybeans were exposed to various concentrations of Mn in nutrient solution and sampled periodically during vegetative growth. Both Mn accumulation and the growth parameters such as dry weight of plant parts, leaf area, and plant height increased exponentially with time. Since the growth parameters responded similarly, the results were expressed as the dry weight of the tops. The relative growth rate (RGR) and relative accumulation rate of Mn (RAR) were calculated. The RGR increased with both increasing temperature and Mn supply whereas the RAR increased primarily with increasing Mn supply. The RGR maximized between 10 and 20 ppb Mn in solution, indicating an adequate plant Mn concentration. At adequate Mn, the RGR increased from 0.08 to 0.12 g g−1 day−1 with increasing temperature and plant Mn increased with the Mn concentration in the nutrient solution. At inadequate Mn, the RGR increased with the Mn concentration in the nutrient solution and plant Mn equilibrated at a minimal concentration the functional requirement that decreased linearly from 7 to 4 µg/g with increasing temperature. Relative growth rate was then expressed as a function of plant Mn concentration and temperature. At higher temperatures, the functional requirement, of Mn was low but on increasing the top Mn concentration, the RGR plateaued at a high rate. On the other hand, at lower temperatures the functional requirement was greater and the RGR with adequate Mn was lower. At the functional requirement, the RGR was governed by the rate of Mn accumulation.

Influence of temperature on the expression of manganese toxicity by two soybean varieties

Two soybean varieties (Glycine max) were grown in nutrient solution to investigate their response to manganese toxicity at two different temperature regimes. Dry matter yields of both varieties were markedly reduced by lower temperature (21°C day/18°C night). At these temperatures leaf crinkle symptoms of Mn toxicity were very severe on Bragg and moderate on Lee at high levels of Mn in solution (15 ppm). However increasing the temperature to 33°C day/28°C night completely eliminated symptoms on both varieties. High levels (15 ppm) of Mn in nutrient solution decreased yields of both varieties at low temperature with Bragg showing the greater reduction. At high temperature neither variety showed yield reductions at 15 ppm Mn. Higher concentrations of Mn in shoots and roots were obtained at higher temperature, indicating that increased tolerance was not associated with lower plant Mn levels. Lee consistantly contained higher levels of Mn in the shoots than Bragg in the 15 ppm Mn solution at both temperatures although appearing to be more tolerant at low temperatures. The implications of these results for environmental effects on the expression of Mn toxicity in the field are discussed. re]19751202

Effect of different iron-, potassium-, phosphate-, and calcium-manganese relationships on the growth and chemical composition of aromatic strain of bidi tobacco (Nicotiana tabacum L.)

In order to study the Mn nutrition ofbidi tobacco plant (Nicotiana tabacum L. aromatic strain 2-1) when it is supplied with nutrient solutions containing different ratios of Mn with Fe, P, K and Ca, a sand-culture experiment was carried out in four different series viz. Fe-Mn, K-Mn, P-Mn and Ca-Mn. No characteristic deficiency symptoms except general loss of green colour and diminished growth were observed at 0.1 ppm Mn in the nutrient solution. Toxicity was observed when Mn in the nutrient solution was 100 ppm and severity of the symptoms decreased with increase in Fe-Mn or K-Mn ratios, but it increased when P-Mn ratio increased while in Ca-Mn series it first decreased and then increased at still higher concentration of Ca on account of chloride ion effect as CaCl2 had to be added to bring about 500 ppm concentration of Ca necessary for the treatment. No symptoms of deficiency or toxicity were observed when Mn in nutrient solution varied from 1 to 10 ppm and Fe-Mn ratio for the leaf varied from 0.4 to 6.1 and its Mn content varied from 190 to 1575 ppm. Slight loss of green colour and plant vigour appeared when Fe-Mn ratio for the leaf was higher than 12.8 even though the Mn content was as high as 90 ppm. Toxic effect due to excessive Mn was felt when Fe-Mn ratio was 0.35 or less and leaf content 1875 ppm or more. Nicotine content was inversely related to the intensity of Mn-toxicity.