Production and Characterization of a Composite Based on Plaster and Juncus Maritimus Plant Fibers

Nowadays,materials with a limited impact on the environment are required in the construction sector.Considering the interesting properties of natural elements such as natural fibers,it seems advantageous to use them to reinforce materials while protecting the environment and guaranteeing economic gain.Along these lines,this research was devoted to studying the effect of untreated natural fibers extracted from the Juncus maritimus plant(from Southern Morocco)on plaster.First,the effect of the percentage of added fibers on the fluidity of the plaster was evaluated by means of the Marsh’s cone method,that is,by measuring the time taken by a known volume of plaster to flow from a cone through a short tube.Then,the highly porous microstructure of the plaster was observed using a scanning electron microscope(SEM).The diffractogram of Juncus maritimus fibers was built by means of a X-ray diffraction(XRD)method.The values obtained for the wet thermal conductivity of the composites decreased from 0.4853 W/m.K for the reference specimen to 0.4324 W/m K for a fiber volume content of 40%.The densities were calculated to determine the lightness of each composite.The mechanical strengths[flexural and compressive]were evaluated for different percentages of rush fibers.The addition of 20%volume fiber was found to improve the flexural strength to 3.63 MPa compared to the sample without fiber(3.36 MPa),thereby ensuring good toughness of the considered material.Nevertheless,a reduction in compressive strength was observed,due to the poor adhesion between the fibers and the plaster matrix.

Microanalysis of Multi-Element in Juncus effusus L. by LIBS Technique

Laser-induced breakdown spectroscopy （LIBS） was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental microanalysis via LIBS. Microanalysis and multimode sampling methodologies were designed in this study. The relative standard deviation （RSD） approach was performed to optimize the multi-shot measurements. Taking advantage of the capability with no or minimal sample pre-treatment of LIBS, a thermodynamic chart of four elements （Mg, Ca, Ba, and Na） was created from twelve collection regions. The diagram of elemental distribution on a micro-scale was generated to explore the nature of Juncus effusus L. by LIBS. The results demon- strated that LIBS is a promising technique for rapid elemental microanalysis of heterogeneous samples.

Experimental culture of non-indigenous Juncus bufonius from King George Island, South Shetland Island, Antarctica

Juncus bufonius L. （Juncaceae） is recognized by the US Department of Agriculture as a weed or invasive plant. Recently, we reported on 3i bufonius L. var. bufonius associated with the native vascular plants Deschampsia antarctica and Colobanthus quitensis in the environs of the Polish Arctowski Station, King George Island, in the Maritime Antarctica. In this study, we evaluated the developmental stages and morphological characteristics of J. bufonius plants cultivated in controlled conditions beginning with seeds obtained from plants of the Antarctic population. Germination occurred at 3 weeks and the germination percentage was low （22.5%）. The average time between the anthesis and seed formation was 7 weeks, similar to that reported for other species in the Juncaceae. According to data reported in the literature, Antarctic individuals were significantly smaller than their relatives growing in other conditions, except for the number of inflorescences. The morphological characteristics of a species vary according to its distribution and the edaphoclimatic environment where it occur; cosmopolitan plants shuch as J. bufonius also have reduced stature in cold environments. The low percentage germination may have been due to water availability in the plant chamber in which the study was conducted. J. bufonius is intolerant of dry environments, and once it suffers hydric stress its recovery is very low; thus, a moister environment could be beneficial. J. bufonius has become established amongst native vegetation near Arctowski Station and without careful control or eradication; it may have the potential to spread far beyond the site, as has happened with the alien grass Poa annua as human disturbance and climate warming increase.

Leaf Wand for Measuring Chlorophyll Fluorescence on Cylindrical Leaves and Its Application on <i>Juncus roemerianus</i>(Black Needlerush)

Chlorophyll fluorescence is a well established technique to rapidly and non-invasively determine photosynthesis parameters in plant leaves. It can be used in both laboratory and field settings, and frequently dark-adaptation of a leaf sample is called for. In the field, this can be accomplished on flat leaves using standard leaf clips supplied by instrument manufacturers. However, not all plant leaves are flat, many are cylindrical or otherwise three-dimensional in shape. The standard leaf clip does not close fully on three-dimensional leaves, therefore, does not allow the sample to be properly dark adapted in the field. A new leaf “wand” was developed that can be slipped over an entire cylindrical leaf or culm of rushes and sedges for both light- and dark-adapted measurements. This new leaf wand is compared to the standard leaf clip (DLC-8) using a Walz mini-PAM on Juncus roemerianus(Black needlerush). Results indicate that dark-adapted yield measurements are not significantly different between leaf clips, while light-adapted yields are higher with the leaf wand. The potential sources of difference in the optical path of the excitation light and fluorescence return are discussed and compared between leaf clips. Construction of specialized leaf wands should be considered for any leaves are not flat and therefore that do not fit the standard leaf clip for complete dark-adaptation under field conditions.

Studies on the chemical components and biological activities of the genus of Juncus

Juncus is the largest genus of Juncaceae family,with about 240 species around the world.There are 77 species,1 variety and 10 deformations grown in China.Up to now,117 components have been identified as phenanthrenes and dihydrophenanthrenes,which are the characteristic constituents of this genus,and 48 ones have been identified as triterpenoids,glycerides,coumarins,flavonoids from this genus.The reported constituents displayed diverse bioactivities,including antiproliferative,antimicrobial,anti-inflammatory,antioxidant,anxiolytic,sedative,spasmolytic,anticholinesterase and antialgal effects.This review summarized the research progress on the chemical components and pharmacological effects of the genus of Juncus so far.

Proline as a biochemical marker in relation to the ecology of two halophytic Juncus species

Aims osmolytes,used for maintaining osmotic balance and as‘osmoprotectants’,are synthesized in plants as a general,con-served response to abiotic stress,although their contribution to stress-tolerance mechanisms remains unclear.Proline,the most common osmolyte,accumulates in many plant species in parallel with increased external salinity and is considered a reliable bio-chemical marker of salt stress.We have measured proline levels in two halophytic,closely related Juncus species under laboratory and field conditions to assess the possible relevance of proline biosynthesis for salt tolerance and therefore for the ecology of these two taxa.Methods Proline was quantified in plants treated with increasing NaCl con-centrations and in plants sampled in two salt marshes located in the provinces of Valencia and alicante,respectively,in southeast spain.Electrical conductivity,pH,Na+and Cl−concentrations were measured in soil samples collected in parallel with the plant material.Important Findings Treatment with NaCl inhibited growth of J.acutus plants in a concentration-dependent manner,but only under high salt conditions for J.maritimus.salt treatments led to proline accumulation in both species,especially in the more salt-tolerant J.maritimus.The results,obtained under laboratory conditions,were confirmed in plants sam-pled in the field.in all the samplings,proline contents were signifi-cantly lower in J.acutus than in the more tolerant J.maritimus growing in the same area.No direct correlation between soil salinity and proline levels could be established,but seasonal variations were detected,with increased proline contents under accentuated water deficit conditions.our results suggest that proline biosynthesis is not only an induced,general response to salt stress but also an important contributing factor in the physiological mechanisms of salt tolerance in Juncus,and that it therefore correlates with the ecology of both species.

Study on the Bacteriostatic Effects of 7 Kinds of Chinese Herbal Medicines such as Ophiopogon japonicus and Comb

[Objective] The aim was to explore the effects of seven kinds of Chinese herbal medicine on Escherichia coil and Staphylococcus aureus in terms of unilater- al bacteriostatic effect, such as root and leaf of Ophiopogon japonicus, honeycomb, Panax pseudoginseng, and Allium macrostemon. [Method] Herbal active ingredients were extracted by water boiling method and a bacteriostatic experiment was per- formed by oxford cup diffusion method, to select Chinese herbs with antibacterial effects. MIC values of seven kinds of Chinese herbal medicine were determined by in vitro half-fold dilution method. [Results] Root and leaf of Ophiopogon japonicus, honeycomb, Panax pseudoginseng, Allium macrostemon, Juncus effusus and Xanthi- um sibiricum had bacteriostatic effects on Escherichia coil and Staphylococcus au- reus in varying degrees. Xanthium and leaf of Ophiopogon japonicus performed bet- ter on Escherichia coil, with MIC values at 7.81 and 15.63 mg/ml, respectively. Panax pseudoginseng and Xanthium performed better on Staphylococcus aureus with MIC values at 15.63 and 31.25 mg/ml. And the drug＇s effect was positively correlated with the concentration. [Conclusion] Xanthium sibiricum is the best bacte- riostatic effect, followed by leaf of Ophiopogon japonicus, and Juncus effusus per- forms the poorest. Panax pseudoginseng showed the best bacteriostatic effect, fol- lowed by Xanthium sibiricum and Juncus effusus performs the poorest. These pro- vide references for clinic safety.

浅议灯心草人工湿地净化水质的作用

人工湿地是一项新兴的污水净化技术。植物是人工湿地系统中的重要部分,在净化污水中发挥重要作用。文章主要总结了灯心草人工湿地在污水净化中的作用。

Effects of light and temperature conditions on flowering in Mat Rush

The effects of photoperiod and light intensity on flowering in Mat Rush cv. Gangshan 3 were studied. The results showed that treatments with longer day length stimulated flowering significantly and increased stem flowering percentage (SFP). Plants treated with low light intensity at early stage had substantially reduced florets per cyme, SFP, tillers per plant and stem length. At middle and late stage, low light intensity significantly reduced SFP. The principal climatic factors affecting SFP were as follows: mean temperatures (MT) of the third ten day period (TDP) in December and of the second TDP in February, actual sunlight hours (SH) of the third TDP in February and precipitation of the third TDP in March. A nonlinear simulation model for SFP was established with experimental results and corresponding climatic data (see Eq.(2)). Simulation by the above equation yielded values the same as those observed from 1992 to 2000, indicating its accuracy in describing the relationship between flowering and light and temperature conditions. The interaction between vernalization and SH is also discussed in this paper.

Halophytic Species in Natural Areas Close to Agricultural Areas of Araban(Gaziantep,Turkey)

As a result of the global warming caused by increasing industrialization, changes in vegetation have occurred on the earth. Halophyte species have been observed in many areas including native vegetation and agricultural land due to increased drought and warming and also over irrigation during formation of secondary vegetation. Soil samples were taken seasonally from selected three areas (Timurlenk, Karapinar and Fakili) in Araban (Gaziantep Turkey) and the pH, electrical conductivity (EC), lime (CaCO3), nitrogen (N), phosphorus (P), potassium (K), sodium (Na) and calcium (Ca) analyzes were performed in this samples. In addition, the presence of taxa known to be halophytes in these areas has been investigated. As a result of the analyses, it was found that there was no seasonal difference (p > 0.05), but there were significant differences between lime (CaCO3), phosphorus (P), potassium (K) and calcium (Ca) among the localities (p Alhagi pseudoalhagi?M. Bieb. was found in Timurlenk and Karapinar, Salsola kali?spp. ruthenica?Iljin was found in Timurlenk and Juncus inflexus?L. was found in Timurlenk, Karapinar, Fakili. Although the soil is not salty, the presence of three different taxa that can tolerate the salt in three localities shows that the amount of salt in the soil may increase in time. The information presented in this study contributes to the salinization of soils and their effects on agriculture in the region.

Growth,phenology and N-utilization by invasive populations of Gunnera tinctoria

Aims Gunnera tinctoria is an unusual N-fixing plant species that has become invasive worldwide,generally in environments with a low evaporative demand and/or high rainfall.Amongst the many mechanisms that may explain its success as an introduced species,a contrasting phenology could be important but this may depend on an ability to grow and utilize nutrients under sub-optimal conditions.We examined whether G.tinctoria has an advantage in terms of a contrasting phenology and N-fixing capability,in comparisons with Juncus effusus,the native species most impacted by G.tinctoria invasions.Methods We made phenological assessments on a weekly or bi-weekly basis on long-established populations on Achill Island,Ireland,during 2016-2017.Data on leaf and inflorescence number,total leaf area,light interception and above-ground biomass were collected alongside measurements of soil temperature,moisture and oxidation-reduction potential.The significance of N-fixing ability for supporting seasonal growth was assessed usingδ15N isotopic assessments,together with in situ acetylene reduction measurements.Important Findings The timing of the initiation of growth of G.tinctoria and J.effusus varied between 2016 and 2017,with the earlier emergence and expansion of leaves of G.tinctoria,and the largest above-ground biomass associated with higher water availability.The early growth of G.tinctoria was dependent on preformed structures,with maximum canopy development occurring in late May,prior to that of J.effusus.Whilst N-fixation was observed in March,this made a more significant contribution to growth during the later stages of canopy development.Based onδ15N isotopic analyses,early growth was predominantly associated with N-remobilization from the rhizomes,whilst seedlings were largely reliant on N-fixation.This emphasizes the importance of nutrient mobilization for early growth and shows that the importance of an N-fixing capability may vary developmentally,as well as during different stages of the invasion process.