Root Iron Content Research Articles

Resistances and Physiological Responses of Impatiens uliginosa to Copper Stress

The phytoremediation of soil and water that has been significantly contaminated with metals has potential ecological and economical ramifications, as well as the advantages of high efficiency, and is an environmentally friendly method of ecological pollution control. This study aimed to examine the impact of varying concentrations of Copper (Cu2+) (0, 5, 10, 15, 20, and 25 mg·L−1) on the growth, development, physiology, biochemistry, mineral elements, and features of Cu2+ enrichment of Impatiens uliginosa. This plant is endemic to Yunnan Province in China and is a wetland species. The results showed that the root lengths, stem diameters, plant height, and stem and leaf biomass of I. uliginosa showed a phenomenon of “low promotion and high inhibition,” while the root biomass showed a trend of gradual decreasing. At the early stage of Cu2+ stress (day 6), the activities of peroxidase and catalase and the contents of malondialdehyde (MDA) of I. uliginosa were directly proportional to the concentration of Cu2+. As the treatment time increased, the activation of a defense mechanism in vivo enabled I. uliginosa to adapt to the high Cu2+ environment, and the content of MDA gradually decreased. As the concentration of Cu2+ increased, its contents in the roots, stems, and leaves also gradually increased. In particular, when the concentration of Cu2+ reached 25 mg·L−1, its contents in the roots of I. uliginosa increased by 39.16-fold compared with that of the control group (CK). The concentration-dependent influence of the contents of iron (Fe) and zinc (Zn) in the roots and leaves were observed. Low concentrations of Cu2+ promoted iron content in roots and leaves, and vice versa, while Zn content decreased with the increasing concentration of Cu2+. It was conclusively shown that I. uliginosa has the potential to remediate low concentrations of Cu2+ pollution in water and is a textbook ornamental plant to remediate bodies of water that are polluted with Cu2+.

The Influence of Copper and Zinc on Photosynthesis and Phenolic Levels in Basil (Ocimum basilicum L.), Borage (Borago officinalis L.), Common Nettle (Urtica dioica L.) and Peppermint (Mentha piperita L.).

This work is aimed at relationships which govern zinc and copper uptake by four popular medicinal herbs: basil (Ocimum basilicum L.), borage (Borago officinalis L.), common nettle (Urtica dioica L.) and peppermint (Mentha piperita L.). They are often grown in soils with significant copper or zinc levels. Herbs were cultivated by a pot method in controlled conditions. Manganese, iron, copper and zinc concentrations were determined by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry. The efficiency of photosynthesis was estimated by measuring the chlorophyll content, water use efficiency, net photosynthesis, intercellular CO2, stomatal conductance, and transpiration rate. Phenolic compounds were determined by the Folin-Ciocalteu method. Analysis of variance showed that herbs grown in soil treated with copper exhibited a lower iron content in roots, while manganese behaved in the opposite way. The only exception was borage, where a decrease in the manganese content in roots was observed. Both copper and zinc supplementations increased the total content of phenolics, while the highest increases were observed for common nettle and basil. Peppermint and borage responded less to supplementation. In the majority of samples, zinc and copper did not significantly affect the photosynthesis. Herbal extracts from common nettle and basil had unique antioxidant properties and may be good free radical scavengers.

Root stoichiometry explains wheat endophytes and their link with crop production after four decades of fertilization

Fertilization can impact root endophytic microbiomes and food production. However, the impacts of decades of continued fertilization on root microbiomes, and their link with ongoing crop production, remain poorly understood. Here, we used a four decade-long fertilization experiment, including contrasting types of organic and inorganic fertilization, to investigate the effects of long-term fertilization on multi-kingdom root endophytic microbiomes, including keystone species (modules within microbial networks), and their indirect associations with the production of wheat, which is one of the most important crops worldwide. We found that long-term inorganic (nitrogen, phosphorus, potassium (NPK)) and organic (NPK with straw (NPKS) and NPK with cow manure (NPKM)) fertilization had significant impacts on the community composition of endophytic arbuscular mycorrhizal fungi (AMF), bacteria, and non-mycorrhizal fungi. In addition, compared with NPK fertilization, NPKS and NPKM amendments significantly decreased the microbial network complexity, which was associated with changes in the root iron content. Finally, we identified an important subset of keystone root endophyte species within the microbial network (Module #2), which was positively correlated with wheat yield, and affected by changes in root carbon to phosphorus ratio. This study provides evidence that long-term fertilization can affect keystone root endophytic species in the root microbiome, with implications for food security in an over-fertilized world.

Dual effects of nZVI on maize growth and water use are positively mediated by arbuscular mycorrhizal fungi via rhizosphere interactions

Nanoscale zero-valent iron (nZVI) might generate positive and negative effects on plant growth, since it acts as either hazardous or growth-promotion role. It is still unclear whether such dual roles can be mediated by arbuscular mycorrhizal fungi (AMF) in plant-AMF symbiosis. We first identified that in 1.5 g kg−1 nZVI (≤1.5 g kg−1 positively), maize biomass was increased by 15.83%; yet in 2.0 g kg−1 nZVI, it turned to be declined by 6.83%, relative to non-nZVI condition (CK, p < 0.05), showing a negative effect. Interestingly, the inoculation of AMF massively improved biomass by 45.18% in 1.5 g kg−1 nZVI, and relieved the growth inhibition by 2.0 g kg−1 nZVI. The event of water use efficiency followed similar trend as that of biomass. We found that proper concentration of nZVI can positively interact with rhizosphere AMF carrier, enabling more plant photosynthetic carbon to be remobilized to mycorrhiza. The scanning of transmission electron microscopy showed that excessive nZVI can infiltrate into root cortical cells and disrupt cellular homeostasis mechanism, significantly increasing iron content in roots by 76.01% (p < 0.05). Simultaneously, the images of scanning electron microscopy showed that nZVI were attached on root surface to form an insoluble iron ion (Fe3+) layer, hindering water absorption. However, they were efficiently immobilized and in situ intercepted by extraradical hyphae in mycorrhizal-nZVI symbiosis, lowering iron translocation efficiency by 6.07% (p < 0.05). Herein, the optimized structure remarkably diminished aperture blockage at root surface and improved root activities by 30.06% (p < 0.05). Particularly, next-generation sequencing demonstrated that appropriate amount of nZVI promoted the colonization and development of Funneliformis mosseae as dominant species in rhizosphere, confirming the positive interaction between AMF and nZVI, and its regulatory mechanism. Therefore, dual effects of nZVI can be actively mediated by AMF via rhizosphere interactions. The findings provided new insights into the safe and efficient application of nanomaterials in agriculture.

Ammonium nutrition interacts with iron homeostasis in Brachypodium distachyon.

Most plant species develop stress symptoms when exposed to high ammonium (NH4+) concentrations. The root is the first organ in contact with high NH4+ and therefore the first barrier to cope with ammonium stress. In this work, we focused on root adaptation to ammonium nutrition in the model plant Brachypodium distachyon. Proteome analysis revealed changes associated with primary metabolism, cell wall remodelling, and redox homeostasis. In addition, it showed a strong induction of proteins related to methionine (Met) metabolism and phytosiderophore (PS) synthesis in ammonium-fed plants. In agreement with this, we show how ammonium nutrition impacts Met/S-adenosyl-Met and PS metabolic pathways together with increasing root iron content. Nevertheless, ammonium-fed plants displayed higher sensitivity to iron deficiency, suggesting that ammonium nutrition triggers impaired iron utilization and root to shoot transport, which entailed an induction in iron-related responses. Overall, this work demonstrates the importance of iron homeostasis during ammonium nutrition and paves a new way to better understand and improve ammonium use efficiency and tolerance.

Synthesis of iron chelates for remediation of iron deficiency in an alkaline and calcareous soil

The present study was aimed to investigate the using iron chelates viz., ferrous glycinate and ferrous citrate for the remediation of iron deficiency in alkaline and calcareous soil. The lab experiment was carried out to study the synthesis of Fe chelates by using organic and amino acid based chelating agents. The Fe chelates were synthesized based on 2:1 molar ratio of chelating agents and metal ions. The synthesized iron chelate was characterized by using Fourier transform infrared spectrophotometer (FT-IR). Finally, the synthesized amino acid and organic acid chelated iron were used to remediate the calcareous soil with black gram as a test crop. Iron content in black gram (above ground mass) tented to fluctuate at different growth stages. The highest shoot iron content of 325, 351 and 347 mg kg-1 at vegetative, flowering and harvest stages were recorded with 1% ferrous glycinate as foliar spraying on 25 and 45 Day after sowing (DAS). The root iron content was also higher in 1% ferrous glycinate as foliar spraying on 25 and 45 DAS. The current investigation affirmed that the utilizing different chelating agents like the ferrous glycinate were powerful than ferrous sulfate, which may build the iron substance and iron take-up of blackgram in various development stages.

Effects of Chitosan on the Uptake of Total Iron, Manganese and Boron in Peach Seedlings

As materials for the study, peach seedlings were sprayed with various concentrations (0, 1, 2, 4 and 6 g/L) of chitosan for the sake of the uptake of total iron, manganese and boron content and a more particular knowledge of the growth of the seedlings. The results in experiment showed that the total manganese content accumulated more in peach seedlings compared with other two elements. The total manganese and boron content in roots and leaves of chitosan-treated seedlings could increase in general. In the wake of the chitosan concentration increased, the total iron content in roots and leaves of seedlings gradually decreased but increased in stems. When it comes to the absorption of nutrients by peach seedlings, there were existing synergism and antagonism in this experiment among iron, manganese and boron, which were good for the growth of peach seedlings.

Effect of vermicompost application on root growth and ginsenoside content of Panax ginseng

Vermicomposts are valuable by-products of organic wastes and can be used to improve soil environments in ginseng production. We compared the effects of food waste vermicompost (FWV), cow manure vermicompost (CMV) and paper sludge vermicompost (PSV) on several ginseng root production variables. Interactions between soil chemical properties, root growth, ginsenoside content and plant mineral content were also investigated. In the PSV treatment, the root yield increased by 40 t ha−1 compared to the untreated control. Nitrate concentration correlated negatively with root yield, and none of the vermicompost treatments differed significantly from the control in terms of root loss. Soil pH correlated positively with root weight, and total ginsenoside content did not vary among treatments, although some individual ginsenosides did differ among treatments. Root iron content correlated strongly with total ginsenoside content, and total ginsenoside content correlated negatively with root yield. Overall, our results showed that the root yield increase was not due to nutrient increase. Vermicompost was safe to use in relation to root rot disease, and it favourably elevated the pH of fields converted from rice paddies to ginseng production. Ginsenoside was not involved in defence mechanisms against root rot disease. Root iron content may have been involved in the metabolism of ginsenoside, and there was an apparent trade-off between ginsenoside content and root yield. Finally, vermicompost application altered resource allocation and soil chemical properties, which led to novel interactions between root parameters and components.

Root associated iron oxidizing bacteria increase phosphate nutrition and influence root to shoot partitioning of iron in tolerant plant Typha angustifolia

Typha angustifolia is a heavy metal tolerant plant that grows in a uranium mine tailings highly contaminated with iron. In this study three iron oxidizing microbes (FeOBs) isolated from Typha rhizoplane were investigated for their role in plant growth promotion (PGP). Their effect on iron nutrition in Typha under iron replete and excess condition was also evaluated. The PGP activities of the FeOBs were studied by measuring their influence on plant growth. To investigate the mechanism of growth promotion their ability to solubilize phosphate, and to produce Indole acetic acid and siderophores were studied. The influence of the FeOBs on root to shoot partitioning of iron was tested by measuring total iron content in roots and shoots treated with microbes. The FeOBs were named as Paenibacillus cookii JGR8, (MTCC12002), Pseudomonas jaduguda JGR2 (LMG25820) and Bacillus megaterium JGR9 (MTCC12001). The siderophore producers, influenced iron accumulation in the plant root. Additionally P. pseudoalcaligenes JGR2 increased shoot iron content overcoming the root- shoot barrier that allows Typha to exclude metals from its shoot. Among the PGP mechanisms tested, ability to solubilize phosphate appeared to be most significant for increasing the plant biomass. FeOBs that produce siderophore increased iron content in plant and therefore can be of immense biotechnological importance. However Biomass increase was directly correlated with increased phosphate acquisition and not with enhanced iron accumulation in Typha.

Uptake and transport of iron ions (Fe+2, Fe+3) supplied to roots or leaves in spinach (Spinacia oleracea L.) plants growing under different light conditions

&lt;p&gt;In experiments carried out in a phytotron using aqueous cultures, there was investigated the effect of root or foliar application of different types of iron salts on spinach plant productivity, leaf and root iron content as well as the rate of transport of iron from the roots to the leaves. Plants were grown in Hoagland's solution with a single concentration at two fluorescent light intensities: 290 and 95 µmol × m&lt;sup&gt;-2&lt;/sup&gt; × s&lt;sup&gt;-1&lt;/sup&gt; PAR. To fertilize the plants, iron was supplied at a dose of 25 mg Fe in the nutrient solution or as foliar sprays using the following salts: 1 – Fe 0; 2 – FeCl&lt;sub&gt;2&lt;/sub&gt; × 4H&lt;sub&gt;2&lt;/sub&gt;O; 3 – FeCl&lt;sub&gt;3&lt;/sub&gt; × 4H&lt;sub&gt;2&lt;/sub&gt;O; 4 – FeSO&lt;sub&gt;4&lt;/sub&gt; × 7H&lt;sub&gt;2&lt;/sub&gt;O; 5 – Fe&lt;sub&gt;2&lt;/sub&gt;(SO&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;3&lt;/sub&gt; × nH&lt;sub&gt;2&lt;/sub&gt;O; 6 – Fe-Cit.&lt;/p&gt;&lt;p&gt;The obtained results showed that the productivity of spinach plants treated with FeCl&lt;sub&gt;2&lt;/sub&gt; and FeSO&lt;sub&gt;4&lt;/sub&gt; using foliar sprays and of those fed with Fe-citrate (Fe-Cit) through the roots was significantly higher than in the case of the other salts used. Root application of the salts used had a significant effect on root iron content, whereas their foliar application significantly affected leaf iron content. In this respect, ferrous salts were generally the most beneficial, while ferric salts were the least beneficial. The rate of transport of iron to the leaves, irrespective of the method of its application, was clearly higher for ferrous salts and Fe-Cit than for ferric salts. The free proline content in the leaves of plants not fertilized with Fe was 2–4 times lower than in plants supplied with this nutrient. An irradiance of 290 µmol × m&lt;sup&gt;-2&lt;/sup&gt; × s&lt;sup&gt;-1&lt;/sup&gt; had a positive effect on plant productivity and root Fe content.&lt;/p&gt;.

COMPARATIVE STUDIES OF PLANT GROWTH AND DISTRIBUTION IN RELATION TO WATERLOGGING

SummaryRooted cuttings of Salix caprea L. and ‐S. cinerea ssp. oleifolia (Macreight) growing in soil were exposed to (a) intermittent, (b) partial and (c) complete waterlogging of the soil. Measurements of growth and other characteristics were compared with unflooded controls. Both species were harmed by waterlogging but S. caprea was more sensitive than 5. cinerea as shown by the greater reduction of height, internode number, dry weight of root, stem and leaf, specific leaf area and leaf area per plant. The waterlogging treatments did not differ amongst themselves in the degree of inhibition of growth which they caused. A single fully waterlogged treatment would thus have been quite adequate in screening for tolerance.The reduction in specific leaf area of S. caprea was probably mediated by reduced turgidity and failure of leaf tissue to expand fully. Leaf iron content increased in both species but less so in S. cinerea, which is able to immobilize more iron in, or on, its roots. 5. caprea leaves contained over 2000 μg g−1 iron, a concentration recorded as toxic in other plants; these leaves became brittle and some lower leaves were shed. Root iron content increased more in S. cinerea than in S. caprea, and this was accompanied by an increase in phosphorus content. Chlorophyll and magnesium content of leaves was significantly reduced in S caprea but not in S. cinerea. Photosynthetic potential was reduced in S. caprea but not in S. cinerea; this was probably unrelated to stomatal control of CO2 uptake. S. cinerea produced adventitious roots at the surface of flooded soil and when cuttings were immersed in water; S. caprea did not. These observations are compatible with the ecology of the two species, S. caprea normally inhabiting better drained soils than 51. cinerea.