Zinc isotopic fractionation in Phragmites australis in response to toxic levels of zinc

Stable isotope signatures of Zn have shown great promise in elucidating changes in uptake and translocation mechanisms of this metal in plants during environmental changes. Here this potential was tested by investigating the effect of high Zn concentrations on the isotopic fractionation patterns of Phragmites australis (Cav.) Trin. ex Steud. Plants were grown for 40 d in a nutritive solution containing 3.2 μM (sufficient) or 2 mM (toxic) Zn. The Zn isotopic composition of roots, rhizomes, shoots, and leaves was analysed. Stems and leaves were sampled at different heights to evaluate the effect of long-distance transport on Zn fractionation. During Zn sufficiency, roots, rhizomes, and shoots were isotopically heavy (δ(66)Zn(JMC Lyon)=0.2‰) while the youngest leaves were isotopically light (-0.5‰). During Zn excess, roots were still isotopically heavier (δ(66)Zn=0.5‰) and the rest of the plant was isotopically light (up to -0.5‰). The enrichment of heavy isotopes at the roots was attributed to Zn uptake mediated by transporter proteins under Zn-sufficient conditions and to chelation and compartmentation in Zn excess. The isotopically lighter Zn in shoots and leaves is consistent with long-distance root to shoot transport. The tolerance response of P. australis increased the range of Zn fractionation within the plant and with respect to the environment.

Adsorption Behavior and Mechanism for the Uptake of Fluoride Ions by Reed Residues

The adsorption behavior and mechanism for the uptake of fluoride ions by untreated and desugared reed residues (roots, stems and leaves) were studied through adsorption experiments, elemental analysis, infrared spectroscopy and surface area analysis. The results showed that the adsorption capacity of untreated and desugared reeds followed the order: desugared roots 2136 mg/kg > desugared leaves 1825 mg/kg > desugared stems 1551 mg/kg > untreated roots 191 mg/kg > untreated stems 175 mg/kg > untreated leaves 150 mg/kg, so adsorption capacity of desugared reeds was larger than that of the untreated reeds. The adsorption kinetic of fluoride ions followed a pseudo-first-order model. A Langmuir model could be used to fit the isothermal adsorption process which was a spontaneous endothermic reaction involving mainly physical adsorption. The ΔG for the uptake of fluoride by the desugared reeds was more negative, so the degree of spontaneity was higher than for the use of the untreated reeds. After samples were desugared, the specific surface area and aromaticity of the reed increased, while the polarity and hydrophilicity decreased, which explained the adsorption amount of desugared reed was higher than that of the untreated. This study enriches techniques and methods of removing fluoride ions from water.

Dietary exposure of the red-crowned crane (Grus japonensis) to total and methyl mercury in Zhalong Wetland, northeastern China

To determine the dietary exposure of the migratory red-crowned crane to mercury (Hg), this study analyzed the concentrations of total mercury (T-Hg) and methyl mercury (MeHg) in its prey, i.e., reeds and three aquatic animal families (Perccottus glenni Dybowski, Cybister japonicus Sharp, and Viviparidae) in northeastern China. Results indicated that the Hg concentration in Zhalong Wetland was elevated through the food chain, and the prey of the red-crowned crane contained measurable levels of T-Hg and MeHg. In prey tissues, MeHg was the main form of the Hg element and accounted for 61% of total Hg concentration in Viviparidae, 58% in C. japonicus Sharp, and 85% in P. glenni Dybowski. The highest T-Hg and MeHg concentrations ranged from 1.66 to 3.89 ppm and from 1.12 to 2.67 ppm, respectively, and they were detected in the feathers of the red-crowned cranes. The lowest T-Hg concentration was determined in the excretions of wild red-crowned cranes at 0.21 ppm; furthermore, the content of MeHg was below the detection limit. In Zhalong Wetland, the level of dietary exposure of the population of red-crowned cranes to Hg is below the threshold of Hg toxicity. Moreover, eggshells are suitable indicators of Hg risk levels to the red-crowned crane.

Small-Scale Habitat-Specific Variation and Adaptive Divergence of Photosynthetic Pigments in Different Alkali Soils in Reed Identified by Common Garden and Genetic Tests

Flexibility of photosynthetic pigment traits is an important adaptive mechanism through which plants can increase mean fitness in a variable environment. Unlike morphological traits in plants, photosythesis has been shown to exhibit phenotypic plasticity, responding rapidly to environmental conditions. Meanwhile, local adaptation at small scales is considered to be rare. Thus, detecting the small-scale adaptive divergence of photosynthetic pigments presents a challenge. Leaf concentrations of photosynthetic pigments under stressful conditions may be reduced or maintained. Concentrations of some pigments and/or ratio of Chlorophyll a (Chla) to Chlorophyll b (Chlb) do not change markedly in some species, such as the common reed, Phragmites australis, a cosmopolitan grass and common invader. Little is known about photosynthetic responses of this plant to varying levels of alkali salt. Few studies have attempted to account for the relationship between pigment accumulation and leaf position in wild plant populations in grasslands. In this study, photosynthetic pigment concentrations and the total Chl(a+b)/Car ratio decreased as the growing season progressed and were shown to be significantly lower in the habitat with a higher soil pH value and less moisture when compared between habitats. The Chla/Chlb ratio did not differ significantly between habitats, although it increased significantly over time. Leaves in the middle position may be functionally important in the response to soil conditions because only pigment concentrations and the Chl(a+b)/Car ratio of those leaves varied between habitats significantly. The outlier loci, used to evaluate molecular signatures of selection, were detected by Arlequin, Bayescan, and Bayenv analyses. In the simulated habitats of common garden, the local genotypes had higher values of Chla, Chlb, Chl(a+b), Car in their home habitat than did genotypes originating from the other habitat. Q_ST-F_ST comparisons provided evidence of divergent selection. It appears likely that soil moisture, pH and electric conductivity drove local adaptation. Combined approaches that utilize information on phenotypes from field and common garden experiments, genome-wide markers, and environmental data will be the most informative for understanding the adaptive nature of the intraspecific divergence.

Characterization of Mechanical and Hygroscopic Properties of Individual Canes of Reed

The search for sustainability has led to the utilization of more ecological materials with at least, a similar structural performance to those used at present. In this regard, reed fits the environmental and structural requirements as it is a sustainable and biodegradable lignin-cellulose material with remarkable mechanical properties. This research confirms the reed’s structural efficiency as it demonstrates that it has excellent strength and stiffness in relation to its density. The reed anisotropy has a large impact on its properties. Indeed, the strength and stiffness parallel to the fibers are clearly higher than in the perpendicular direction. The results confirm that strength and stiffness decrease with the moisture content and nodes act as reinforcement in compression and bending. If compared with steel, timber and concrete, the reed possesses the highest value for strength. Hence, reed constitutes a strong candidate for environmentally friendly engineering.

Optimization of Thermal Conductivity vs. Bulk Density of Steam-Exploded Loose-Fill Annual Lignocellulosics

Lignocellulosic biomass (LCB)-based thermal insulation materials available in the market are more expensive than conventional ones and consist mainly of wood or agricultural bast fibers which are primarily used in construction and textile industries. Therefore, it is crucial to develop LCB-based thermal insulation materials from cheap and available raw materials. The study investigates new thermal insulation materials from locally available residues of annual plants like wheat straw, reeds and corn stalks. The treatment of raw materials was performed by mechanical crushing and defibration by steam explosion process. Optimization of thermal conductivity of the obtained loose-fill thermal insulation materials was investigated at different bulk density levels (30-45-60-75-90 kg m^-3). The obtained thermal conductivity varies in range of 0.0401-0.0538 W m^-1 K^-1 depending on raw material, treatment mode and a target density. The changes of thermal conductivity depending on density were described by the second order polynomial models. In most cases, the optimal thermal conductivity was revealed for the materials with the density of 60 kg m^-3. The obtained results suggest the adjustment of density to achieve an optimal thermal conductivity of LCB-based thermal insulation materials. The study also approves the suitability of used annual plants for further investigation towards sustainable LCB-based thermal insulation materials.

Physiological and Proteomic Analyses of Different Ecotypes of Reed (Phragmites communis) in Adaption to Natural Drought and Salinity

Drought and salinity are the two major abiotic stresses constraining the crop yield worldwide. Both of them trigger cellular dehydration and cause osmotic stress which leads to cytosolic and vacuolar volume reduction. However, whether plants share a similar tolerance mechanism in response to these two stresses under natural conditions has seldom been comparatively reported. There are three different ecotypes of reed within a 5 km2 region in the Badanjilin desert of Northwest China. Taking the typical swamp reed (SR) as a control, we performed a comparative study on the adaption mechanisms of the two terrestrial ecotypes: dune reed (DR) and heavy salt meadow reed (HSMR) by physiological and proteomic approaches coupled with bioinformatic analysis. The results showed that HSMR and DR have evolved C4-like photosynthetic and anatomical characteristics, such as the increased bundle sheath cells (BSCs) and chloroplasts in BSCs, higher density of veins, and lower density and aperture of stomata. In addition, the thylakoid membrane fluidity also plays an important role in their higher drought and salinity tolerance capability. The proteomic results further demonstrated that HSMR and DR facilitated the regulation of proteins associated with photosynthesis and energy metabolism, lipid metabolism, transcription and translation, and stress responses to well-adapt to the drought and salinity conditions. Overall, our results demonstrated that HSMR and DR shaped a similar adaption strategy from the structural and physiological levels to the molecular scale to ensure functionality in a harsh environment.

Bioaccumulation of metals in reeds collected from an acid mine drainage contaminated site in winter and spring

Wetland plants such as Phragmites australis has been used to treat acid mine drainage (AMD) contaminated soil which is a serious environmental issue worldwide. This project investigated metal plaque content(s) and metal uptake in reeds grown in an AMD field in winter and spring. The results indicated that the level of Fe plaque was much higher than Mn and Al plaque as the soil contained more Fe than Al and Mn. The amounts of Mn and Al plaque formed on reeds in spring were not significantly different from that in winter (p > .05). However, more Fe plaque was formed on reeds collected in spring. The concentrations of metals in underground organs were positively related to the metal levels in soils. More Mn and Al transferred to the aboveground tissues of reeds during the spring while the Fe levels in reeds did not significantly vary with seasons. Roots and rhizomes were the main organs for Fe sequestration (16.3 ± 4.15 mg/g in roots in spring) while most Al was sequestered in the shoots of reeds (2.05 ± 0.09 mg/g in shoots in spring). Further research may be needed to enhance the translocation of metals in reeds and increase the phytoremediation efficiency.

Metal storage in reeds from an acid mine drainage contaminated field

Phragmites australis has been used to treat acid mine drainage (AMD)-contaminated soil. However, the mechanism about metal translocation in reeds was not widely reported. This study investigated metal (Fe, Al, and Mn) storage location in reeds grown in five different sampling sites of an AMD field. As expected, the more metals in soil, the more metals entered the belowground organs of plants. Reeds grown in soils with the highest levels of metals accumulated 0.16 ± 0.04 mg/g Mn, 16.29 ± 4.15 mg/g Fe, and 1.31 ± 0.22 mg/g Al in roots. Most of the iron was sequestered in the roots, while Al was transferred to the shoots. Histological staining found that most of the iron was sequestered in the exodermis, while Al extended the endodermis of roots. Al even entered the stele of roots grown in soil with higher Al levels. The epidermis, cortex, and central cylinder of rhizomes were the main tissues for Fe and Al storage. The more metals in rhizomes, the stronger intensity of the staining was observed around the vascular systems of rhizomes. No structural difference was observed among reeds collected from different sites. Further studies may be needed to enhance the transfer of metals in reeds and increase the phytoremediation efficiency.

[Phosphate Control Effect and Water Body Remediation of Magnesium Modified Reed Biochar]

Adding biochar from harvested reed to sediments is a new method to control the release of sedimentary phosphorus. Three types of Mg-modified biochars were prepared by pyrolysis of reed modified by magnesium chloride at 300, 450, and 600℃.The phosphate adsorption characteristics of the three types of biochars were analyzed by isothermal adsorption experiments. Biochar MBC-450 with good phosphate adsorption effects was selected as the material for the following experiments. Taking the sediment and overlying water of a campus river as the experimental object, we studied the adsorption of phosphate in overlying water and the control of sedimentary phosphorus by Mg-modified biochar under different dosage modes (mixing and covering). The concentration of DIP in the overlying water could be effectively reduced by biochar mixing and covering, and the accumulative phosphorus adsorption capacity increased by 17.3% (mixing) and 11.7% (covering) compared with that of the control. The control effect of sedimentary phosphorus by biochar mixing was more obvious; the DIP in sedimentary water decreased by 14.7%, 18.9%, and 35.36% from 0-2 cm to 4-6 cm compared with the control. The DIP in sedimentary water decreased by 33.3%, -28.2%, and 12.9% when covered with biochar. Compared with the control, the proportion of NH₄ Cl-P in the sediment of 0-2 cm and 2-4 cm increased by 15% and 15% (mixing) and 12% and 2% (covering), respectively, while BD-P in TP decreased by 7% and 9% (mixing) and 6% and 3% (covering), respectively, and the Al-P in TP decreased by 7% and 6% (mixing) and 7% and -1% (covering), respectively. The other forms of phosphorus did not change significantly. Biochar mixing and covering can both improve the microbial activity in surface sediment, and biochar mixing can improve the microbial activity in deeper sediments more significantly.

Development of reed-based cellulose aerogel: a sustainable solution for crude oil spill clean-up

This study focused on fabricating a cellulose aerogel for oil spill clean-up, using common reed (Phragmites australis) as the cellulose source. The process involved isolating cellulose from reed via traditional Kraft pulping, considering the effects of key factors on the isolated cellulose content. After a two-stage HP bleaching sequence, the highest cellulose content achieved was 27.2%, with 80% ISO brightness and 1% ash content under mild Kraft pulping conditions of 30% sulfidity, 20% active alkali (AA), sustained cooking at 165°C for 3 h, and a liquor-to-reed ratio of 8 : 1. Subsequently, reed-based cellulose aerogel was fabricated via a freeze-drying method using an eco-friendly NaOH/poly(ethylene glycol) aqueous solvent system, which was then modified with methyltrimethoxysilane. The resulting aerogel exhibited remarkable characteristics, including a low density of 0.04 g cm-3, high porosity of 96%, high hydrophobicity with a water contact angle (WAC) of 141°, and a superior crude oil adsorption capacity of 35 g g-1. Comprehensive characterizations of the fabricated materials, including scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis/differential scanning calorimetry, and WAC measurements, were evaluated. This interdisciplinary study explores the commercial promise of reed-based cellulose aerogel as a sustainable solution for oil spill clean-up efforts.

[Effect of reed-biochar application on ammonia volatilization from different types of soils]

The application of straw biochar in farmland in Dongting Lake area can realize the resource utilization of straw and reduce environmental risk. In 2020, a rice pot experiment was conducted to investigate the effects of different biochar application levels on ammonia volatilization rate, cumulative ammonia volatilization, pH value, and NH₄⁺-N concentration in surface water. Six levels of reed (Miscanthus lutarioriparius) biochar amount, i.e., 0%, 1%, 2%, 4%, 6% and 8% of soil weight of the 0-20 cm column, were applied in two typical paddy soils in sou-thern China, i.e., reddish clayey soil derived from quaternary red soil and granitic sandy soil derived from granite. Compound fertilizer was applied at a rate of 200 kg N·hm^-2. The results showed that biochar application resulted in significant differences in the rate and cumulative amount of ammonia volatilization between the two soils and among different biochar treatments. For the granitic sandy soil, peak ammonia volatilization under different biochar treatments appeared at the second day after fertilization, which was decreased by 23.6%-53.4%. For the reddish clayey soil, peak ammonia volatilization appeared between the 7th to 13th day after fertilization, which increased with biochar addition level. The rate of ammonia volatilization from the granitic sandy soil was generally higher than that from the reddish clayey soil. For the granitic sandy soil, addition of <4% biochar could inhibit the ammonia volatilization and cumulative volatilization amount, with the greatest reduction (46.9%) at the treatment with 2% biochar addition. The addition of biochar did not affect the pH value of surface water at the early stage of rice growth. For the reddish clayey soil, the pH value and NH₄⁺-N concentration in the surface water increased with biochar addition level, resulting in the increases of ammonia volatilization rate and cumulative volatilization amount by 1.3-10.5 times. Biochar addition level was the key factor affecting ammonia volatilization from the two soils. Elovich equation could well fit the variation trend of cumulative ammonia volatilization with time for the two soils, with the correlation reaching extremely significant level for each treatment. Overall, the application of reed biochar could suppress ammonia volatilization from the granitic sandy soil which was nearly neutral in acidity, while would promote ammonia volatilization via increasing pH value and NH₄⁺-N concentration of surface water for the acidic reddish clayey soil. Therefore, appropriate dosages of reed biochar should be selected for different types of soil in order to reduce nitrogen loss.

Mold Fungal Resistance of Loose-Fill Thermal Insulation Materials Based on Processed Wheat Straw, Corn Stalk and Reed

The present study evaluates the mold fungal resistance of newly developed loose-fill thermal insulation materials made of wheat straw, corn stalk and water reed. Three distinct techniques for the processing of raw materials were used: mechanical crushing (Raw, ≤20 mm), thermo-mechanical pulping (TMP) with 4% NaOH and steam explosion pulping (SEP). An admixture of boric acid (8%) and tetraborate (7%) was applied to all processed substrates due to their anti-fungal properties. The fourth sample group was prepared from SEP substrates without added fungicide (SEP*) as control. Samples from all treatments were separately inoculated by five different fungal species and incubated in darkness for 28 days at 28 °C and RH > 90%. The highest resistance to the colonization of mold fungi was achieved by TMP and SEP processing, coupled with the addition of boric acid and tetraborate, where molds infested only around 35% to 40% of the inoculated sample area. The lowest mold fungi resistance was detected for the Raw and SEP* samples, each ~75%; they were affected by rich amount of accessible nutrients, suggesting that boric acid and tetraborate additives alone did not prevent mold fungal growth as effectively as in combination with TMP and SEP treatments. Together, the achieved fungal colonization scores after combined fungicide and pulping treatments are very promising for the application of tested renewable materials in the future development of thermal insulation products.

Comparative Analysis of Macro/Microstructures and Constituents of Sorghum and Reed Straw

Node-containing straws exhibit superior mechanical properties compared to node-free straw plants, particularly in terms of shear resistance and compression resistance. We explore the relationship between the structure and mechanical properties of straw materials, providing deeper insights for the field of biomechanics. In this study, we focused on two node-containing straw plants, namely sorghum and reed. The main characteristics of sorghum and reed stalks were compared using macroscopic observation, stereomicroscopy, scanning electron microscopy, infrared spectroscopy, and EDS analysis. This study revealed numerous similarities and differences in the macro- and microstructures as well as the elemental composition of sorghum and reed stalks. The functional groups in sorghum and reed stalks were largely similar, with the primary elements being C and O. Distinguishing features included a higher tapering and a slightly larger reduction in wall thickness in sorghum stalks compared to reed stalks. The cross-section of sorghum stalks was filled with pith structures, while reed stalks exhibited a hollow structure. The vascular bundles in sorghum typically showed a paired arrangement, whereas those in reeds were arranged in odd numbers. Furthermore, sorghum straws contained more Cl and no Br, while the parenchyma of reed straws contained higher Br. The C and O proportions of sorghum straws and reed straws are 50-53% (50-51%) and 45-46% (48-49%), respectively. These variations in elemental composition are believed to be correlated with the mechanical properties of the materials. By conducting a detailed study of the micro/macrostructures and material composition of sorghum and reed straw, this paper provides valuable insights for the field of biomechanics.

Removal of nitrogen and phosphorus by aboveground biomass of Phragmites australis in Constructed Wetland System under the conditions of temperate continental climate

In this paper, aboveground biomass and basic nutrients removal, nitrogen (N) and phosphorus (P), was analyzed by the use of reed as the main component of Constructed Wetland System (CWS) "Gložan". In almost ideal conditions of temperate continental climate, with favorable substrate humidity, due to the constant inflow of municipal wastewater, reed populations reach a high density, on average 217 ind/m². The reed produces significant aboveground biomass, fresh weight (FW) of 144.21 g/plant and dry weight (DW) of 77.04 g/plant, with the largest share being per tree (87.49 g FW/plant, 48.17 g DW/plant), then leaf (49.45 g FW/plant, 24.89 g DW/plant) and the smallest inflorescence (7.27 g FW/plant, 3.99 g DW/plant). The results obtained in this way indicate that the largest amount of nitrogen was removed by leaves, then by stems and, the smallest by inflorescences, 181.07 g/m², 97.73 g/m², 23.41 g/m², respectively. Thus, an average of 302.21 g/m² of nitrogen was removed by the entire aboveground part of the reed. Also, the largest amount of phosphorus was removed by leaves, then by stems, and the smallest by inflorescences, 5.72 g/m², 4.82 g/m² and 2.57 g/m², respectively, while the entire aboveground part of the reed is on average about 13.11 g/m².

Degradation Characteristics of Reed-Based PBAT Mulch and Their Effects on Plant Growth and Soil Properties

Poly (butylene adipate-co-terephthalate) (PBAT) and PBAT/reed fiber (RF) mulch films were prepared. The molecular structural changes and surface morphological evolution during the degradation process were systematically characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The prepared PBAT/RF mulch film biodegradation rate reached 90.43% within 91 days under controlled composting conditions, which was 9.52% higher than a pure PBAT mulch film. The effects of adding PBAT and PBAT/RF microplastics on soil properties and soybean physiological indicators were dynamic. The study demonstrated that the incorporation of 5% PBAT/RF mulch film fragments into soil led to a 5.1% reduction in soil pH and a 17.2% increase in soluble organic carbon content. While the effects of 5% PBAT/RF on soil urease and neutral phosphatase activities were non-significant, sucrase activity decreased by 7.4% and catalase activity was reduced to 0.38 U/g. Additionally, the addition of 5% PBAT/RF resulted in a soybean germination rate of 93.74%, which was 4.0% higher than that observed in the group treated with 5% PBAT alone. The experimental data revealed a 7.2% reduction in leaf chlorophyll content, with concomitant growth inhibition in the soybean seedlings. The study demonstrated that the PBAT/RF composite film achieved 89% biodegradation within 180 days under field conditions, effectively mitigating post-application effects on agroecosystems compared to conventional polyethylene mulch.