Properties of Phragmites australis for Insulating Concrete Application

The common reed, Phragmites australis, is a plant species quite similar to the currently used bio-based aggregates and available on most continents. The purpose of this work is to characterise this common reed and compare its properties to other plants already studied for building use. This study presents the different properties focussing on Phragmites australis chemical composition, hydrophobicity nature and how this character could be explained. To that end, wettability and also water adsorption measurements were carried out on plant flour and aggregates in comparison to miscanthus, wood and hemp shiv properties. Formulations based on reeds of different origins and using different binders (lime and earth) were tested in compression and with thermal conductivity measurements in order to evaluate the behaviour of the reed as a material for building use.

Efecto de la poda de macrófitas sobre microorganismos adheridos al medio de soporte y la carga orgánica en humedales artificiales

Esta investigación evaluó el efecto de la poda de macrófitas sobre microorganismos adheridos al medio de soporte y la remoción de DBO5 en tres humedales artificiales de flujo subsuperficial (HAFS) experimentales con especies de Phragmites australis (HAFS-Carrizo), Pontederia sagittata (HAFS-Tule) y grava como testigo (HAFS-Grava). Se utilizaron nueve unidades (con réplicas). Los HAFS con 1.2 m de ancho, 2.5 m de largo y 0.5 m de profundidad se alimentaron con 200 L/d agua residual doméstica. Las variables estudiadas al medio de soporte fueron microorganismos adheridos, porosidad, densidad, diámetro y humedad para estimar el tiempo de retención y conductividad hidráulica. En las especies se midieron las variables de productividad después de la poda y se estimó la remoción y el coeficiente cinético de degradación k para la DBO5. El experimento fue un diseño de un factor (tratamiento) con tres niveles (HAFS-Tule, HAFS-Carrizo y HAFS-Grava); se evaluaron durante tres meses, después del año de operación. Los tratamientos se evaluaron mediante Anova (paramétricos) y la prueba de rangos de Kruskal-Wallis (no paramétricos) entre grupos antes y después de podar (p < 0.05). La grava presentó en promedio (N = 12) 22.92 ± 1.47 % de humedad, 2.32 ± 0.15 cm de diámetro, densidad de partícula 2.71 ± 0.10 gr/cm3 y porosidad de 36.52 ± 3.36 %, el TRH fue de 3.1 días en todos los tratamientos. El mejor tratamiento fue HAFS-Tule: antes de la poda la biomasa de microorganismos presentó valores medianos (N = 12) de 42931.6 mg/kg (Q1 = 40259.7; Q3 = 54478.4) y posterior a la poda de 33444.6 mg/kg (Q1 = 31210.9; Q3 = 36581.8), la biomasa vegetal retirada en la poda fue de 40.85 ± 2.58 kg, se removió 95.44 % de DBO5 con una k = 1.004 días-1 (27.6 °C), lo que permite cumplir la NOM-001-Semarnat-1996.

The Employment of Endophytic Bacteria for Phytodegradation of Pyridine

Pyridine is considered a heterocyclic aromatic chemical that is poisonous and carcinogenic to a variety of living species. The use of plant and endophytic- bacteria to improve the efficiency of pollutants extraction is considered a viable technique since the endophytic bacteria help in the adaptation of the plant itself in various ecosystems and have significant ecological importance because they improve the soil fertility and quality. This research aims to stimulate the pyridine phytodegradation by Phragmites australis plants using the endophytic bacterial strain, Acinetobacter by inoculation these bacterial cells to the plants to see if it might increase plant growth and pyridine phytodegradation. In the present study, the system of pyridine phytodegradation basins with the vertical subsurface flow (VSSF) was adopted, since this system has better ventilation. In addition, the retention time is several hours due to the penetration of water molecules to the layers of packing materials of the basin, which have a relatively high hydraulic conductivity. After conducting the experiments, samples were collected and tests were done to find out the optimum conditions. The results were recorded as 40 plants of P. australis/m2 of VSSF systems; bacterial cells concentration, 250 mg/L; pyridine concentration, 400 mg/L; temperature, 35 °C and pH, 8±2 for 10 hrs incubation duration. As a result, endophytic bacteria can break down toxic organic substances in combination with certain plants. When the endophytic bacterium, Acinetobacter was not used to enhance the role of Phragmites australis plants in the pyridine-phytodegradation process, the rate of phytodegradation was reduced to less than 30% at a pyridine concentration of 700 mg/L, indicating the importance of this endophytic bacterium in the pyridine phytodegradation process.

Материалы к флоре болот Тамбовской области

Тамбовская область находится в лесостепной природной зоне, которая характеризуется сравнительно низкой заболоченностью и сильным преобразованием естественных ландшафтов. В XX веке болота подверглись значительному антропогенному воздействию, что отразилось на флоре, но почти не было зафиксировано в публикациях последних трех десятилетий. Нами в 2011–2021 гг. маршрутно-ключевым методом обследовано 46 болот в 13 районах Тамбовской области, на основе полученных результатов составлен список высших растений, указано их распределение по основным типам болот (низинные, переходные, верховые) и встречаемость. На болотах Тамбовской области выявлено 158 видов сосудистых растений (108 родов и 55 семейств) и 33 вида мхов (14 родов и 9 семейств). Наиболее часто на болотах региона из сосудистых растений встречались Salix cinerea, Typha latifolia, Lysimachia vulgaris, L. thyrsiflora, Carex acuta, Betula pubescens, Calamagrostis canescens, Phragmites australis, Lycopus europaeus, из мхов – Sphagnum fallax, S. flexuosum, S. angustifolium. На болотах зафиксированы популяции 22 видов, включённых в Красную книгу Тамбовской области. БлагодарностиРабота проведена в рамках выполнения государственного задания 121051100099-5.

Correlations Between Root Metabolomics and Bacterial Community Structures in the Phragmites australis Under Acid Mine Drainage-Polluted Wetland Ecosystem

Despite root microecology playing critical role in plant growth and fidelity, relatively few studies have focused on the link between the microbial communities and root metabolome in the aquatic macrophytes under heavy metal (HM) pollution. Using high-throughput metagenomic sequencing, targeted metabolomics and community-level physiological profile analyses, we investigated the symbiotic associations between Phragmites australis with rhizospheric bacterial communities under differing acid mine drainage (AMD) pollution. Results indicated that AMD pollution and root localization significantly affected root metabolome profiles. Higher accumulation of adenosine monophosphate, inosine, methionine, carnitine and dimethylglycine were observed in the rhizosphere under AMD than non-AMD habitat. Overall, the bacterial diversity and richness, and functional (metabolic) diversity were lower under high-AMD pollution. While non-AMD site was enriched with members of phylum Firmicutes, Proteobacteria were the most abundant taxa in the rhizosphere and endosphere under AMD-polluted sites. Further, plant growth promoting rhizobacteria (Rhizobium, Delftia, Bradyrhizobium, and Mesorhizobium) and metal-tolerant bacteria (Bacillus, Arthrobacter, Massilia and Methylocystis) were most abundant in AMD-polluted than non-AMD habitat. Finally, pH, TDS (total dissolved solids), Cu, Cr, Fe, and Zn content were the key environmental factors that strongly contributed to the spatial perturbation of rhizospheric metabolites, proteobacterial and acidobacterial taxa. Overall, the study linked the differential endospheric and rhizospheric bacterial community and metabolite profiles in P. australis under AMD environment and provided insights into HM adaptability and phytoremediation potential.

Effect of Soil Water Contents on Arsenic Accumulation in Phytoliths of Pteris Multifida and Phragmites Australis

Purpose: The encapsulation of toxic metal(loid)s in phytoliths represents a new area of research. The accumulation of metal(loid)s in phytoliths can alter the fate and toxicity of soil metal(loid). Pteris multifida is a well-known As hyperaccumulator which also harbors phytoliths. However, As accumulation in phytoliths has not yet been studied. Soil water content is considered the main factor influencing phytolith accumulation and also remains unexplored with respect to As accumulation in phytoliths. In this study, As concentration in the phytoliths of P. multifida was compared with that in Phragmites australis phytoliths as a function of the soil water content. Methods: P. multifida and P. australis were grown under different soil water contents. The As concentration in phytoliths, roots, and shoots of plants was then determined.Results: The range of As concentration in the phytoliths of P. multifida was 414.70 - 1610.74 mg kg-1, and that for P. australis phytoliths was 41.67 - 126.54 mg kg-1. In P. multifida, higher soil water content increased As accumulation in phytoliths but did not affect phytolith content in the plant. In P. australis, the higher soil water content increased phytolith content in the plant but decreased As concentration in phytoliths. Conclusion: This study suggests that P. multifida has higher As content in phytoliths than P. australis, and this accumulation can be affected by soil water content. The current findings provide insight into the accumulation of As in phytoliths and provide a theoretical basis for our understanding on the fate of As in the environment.