Effects of Spatial Expansion Between Phragmites Australis And Cyperus Malaccensis On Temporal Variations And Bioaccumulation of Vanadium In Coastal Marshes of The Min River Estuary, Southeast China

Vanadium (V) plays important roles in physio-ecological processes of marsh plants. To investigate the effects of spatial expansion between native invasive species (Phragmites australis, PA) and common native species (Cyperus malaccensis, CM) on temporal variations and bioaccumulation of V in coastal marshes of the Min River estuary, in situ filed sampling was conducted in PA marsh (PAM, before expansion), CM marsh (CMM, before expansion) and ecotonal marsh (EM, during expansion, marsh plants were denoted by PA' and CM') at different seasons by space-for-time substitution method. Results showed that, over all sampling seasons, the mean V contents in marsh soils ranged from 99.71 to 108.41 mg·kg-1 which exceeded its background value in soils of Fujian province (78.3 mg·kg-1). The V levels in soils differed among seasons or marshes. Higher V contents in soils of PAM, EM and CMM generally occurred in spring and winter. Over all sampling seasons, the V levels in profiles of EM were much higher than those of PAM and CMM. The temporal variation of V levels in soils of EM might rest with the alterations of soil pH, SOM and plant ecological traits during the spatial expansion. Although the V contents in PA, PA', CM' and CM differed among tissues, both the roots/stems (R/S) and roots/leaves (R/L) ratios were larger than 1 while the stems/leaves (S/L) ratios were less than 1, implying that the values in roots were much higher than those in other tissues. The V levels in tissues differed among species or seasons, which could be interpreted by the differences in ecological traits among plants and the competitive absorption for V by plants during the spatial expansion. Allocations of V in organs differed among seasons or species and roots were the main V stock of plant subsystems. This paper found that the V in soils of the Min River estuary existed enrichment process and the spatial expansion between PA and CM promoted its enrichment in soils and its bioaccumulation by plants.

Shewanella cyperi sp. nov., a facultative anaerobic bacterium isolated from mangrove sediment

Two Gram-stain-negative, motile, facultatively anaerobic, rod-shaped strains, FJAT-53720T and FJAT-53726, were isolated from rhizosphere sediment of plant Cyperus malaccensis. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that strains FJAT-53720T and FJAT-53726 were affiliated to the genus Shewanella (forming an independent cluster) with the highest sequence similarity to the type strain of Shewanella algae . Optimum growth of both strains was observed at 30 °C and pH 7. The respiratory quinones were Q-7, Q-8 and MK-7. The polar lipid profile included phosphatidylmethyl ethanolamine, phosphatidylethanolamine, diphosphatidylglycerol, one unidentified aminophospholipid and four unknown phospholipids. The major fatty acids of strains FJAT-53720T and FJAT-53726 were iso-C15:0, C17 : 1 ω8c and summed feature 3. The genomic DNA G+C content of strain FJAT-53720T was 55.6 mol%. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between FJAT-53720T and FJAT-53726 were 97.4 and 77.9 %, confirming that they were similar species and hence FJAT-53720T was selected for further analysis. The ANI and dDDH values between FJAT-53720T and other members of the genus Shewanella were below the cut-off level (95–96 %; 70 %) for species delineation. Based on the above results, FJAT-53720T represents a novel species of the genus Shewanella , for which the name Shewanella cyperi sp. nov. is proposed. The type strain is FJAT-53720T (=KCTC 82444T=GDMCC 1.2207T).

Spatial-temporal Distribution of Salt Marshes in Intertidal Zone of China during 1985-2019

Based on the cloud platform of Google Earth Engine (GEE), this study selected Landsat 5/8 and Sentinel-2 remote sensing images and used Support Vector Machine (SVM) classification method to classify the 35 years of intertidal salt marshes in China, and verified the classification results in combination with field survey. Finally, combining with various driving factors, the reasons and laws affecting the changes of salt marshes species and area were discussed and analyzed. The main results of the study are as follows:The main types of salt marshes plants in China include Phragmites australis, Spartina alterniflora, Suaeda salsa, Scirpus mariquete, Tamarix chinensis, Cyperus malaccensis and Sesuvium portulacastrum. The results salt marshes classification indicated that 166999.32 ha in 1985, 172893.87 ha in 1990, 174952.29 ha in 1995, 125567.51 ha in 2000, 93257.97 ha in 2005, 102539.04 ha in 2010, 96302.92 ha in 2015, and 115722.75 ha in 2019. The main driving factors of salt marsh change from 1985 to 2015 are reclamation, mudflat aquaculture, climate change, coastal zone erosion, invasion of alien species, and natural competition and succession among salt marshes species. The results can be used to quantitatively analyze the salt marshes carbon storage in space and time, and provide data support for the protection of salt marsh wetlands, the restoration of ecological functions and the implementation of "carbon neutral".

Promising Mechanical, Thermal, and Ballistic Properties of Novel Epoxy Composites Reinforced with Cyperus malaccensis Sedge Fiber

Composites reinforced with natural lignocellulosic fibers (NLFs) are gaining relevance as the worldwide demand for renewable and sustainable materials increases. To develop novel natural composites with satisfactory properties, less common NLFs should also be investigated. Among these, the Cyperus malaccensis (CM), a type of sedge fiber, is already used in simple items like ropes, furniture, and paper, but has not yet been investigated as composite reinforcement for possible engineering applications. Therefore, the present work evaluated for the first time the properties of novel epoxy composites incorporated with 10, 20, and 30 vol.% of CM sedge fibers. Tensile, Izod-impact, and ballistic impact tests were performed, as well as Fourier transform infrared (FT-IR) spectroscopy and thermal analysis of the composites. Results disclosed a decrease (−55%) in tensile strengths as compared to the neat epoxy. However, the elastic modulus of the 30 vol.% sedge fiber composite increased (+127%). The total strain and absorbed ballistic energy did not show significant variation. The Izod impact energy of the 30 vol.% composite was found to be 181% higher than the values obtained for the neat epoxy as a control sample. An increase in both stiffness and toughness characterized a reinforcement effect of the sedge fiber. The thermal analysis revealed a slight decrease (−15%) in the degradation temperature of the CM sedge fiber composites compared to the neat epoxy. The glass-transition temperatures were determined to be in the range of 67 to 81 °C.

HIỆN TRẠNG CANH TÁC VÀ THÀNH PHẦN CÔN TRÙNG TRÊN CÂY CÓI (Cyperus malaccensis Lam) TẠI HUYỆN CÀNG LONG, TỈNH TRÀ VINH

Nghiên cứu này nhằm xác định hiện trạng canh tác và thành phần côn trùng trên ruộng cói tại huyện Càng Long, tỉnh Trà Vinh. Phương pháp nghiên cứu gồm điều tra 100 nông hộ đang canh tác cây cói của huyện Càng Long và khảo sát ngoài đồng. Kết quả cho thấy mỗi nông hộ có 2-3 lao động với nhiều kinh nghiệm canh tác (6-20 năm). Trong kỹ thuật canh tác, 100% nông hộ chỉ sử dụng phân hóa học với liều lượng trung bình 280N + 140P2O5 + 110 K20 (kg ha-1) và không sử dụng phân hữu cơ. Dịch hại quan trọng đối với cây cói là sâu đục thân (98% nông hộ) và bệnh đốm vàng (100% nông hộ) với khả năng làm chết cây cói ở tỉ lệ cao và xuất hiện quanh năm và 100% nông hộ sử dụng thuốc hóa học để quản lý. Cây cói cho thu nhập tương đối cao và phần lớn nông hộ không có ý định chuyển sang cây trồng khác (95% nông hộ). Việc canh tác cây cói có nhiều thuận lợi như nông hộ có nhiều kinh nghiệm, thu nhập ổn định và đất đai thích hợp, khó khăn chủ yếu là vấn đề dịch hại và thiếu nước vào mùa khô. Kết quả cũng cho thấy có 11 loài côn trùng gồm 08 loài côn trùng gây hại (0,04 – 51,5 con/m2) và 03 loài côn trùng có ích (0,26 - 1,63 con/m2).