Invasive Plant Alternanthera Philoxeroides Research Articles

Greater capacity for division of labor brings greater benefits to an invasive clonal plant than its native partners

The majority of problematic invasive plants exhibit clonal growth, and the clonal traits are widely recognized as critical determinants contributing to their invasiveness. Division of labor represents a crucial advantage associated with clonal growth; therefore, it is reasonable to anticipate that this particular trait may confer a growth advantage upon invasive clonal species in comparison to native ones. To test this hypothesis, we conducted a comparative experiment in the greenhouse involving the highly invasive plant Alternanthera philoxeroides, its native congener A. sessilis, and its native co-occurring Jussiaea repens. We grew clonal fragments of these three stoloniferous plants under negative spatial covariance of light and soil nutrients while either preventing or allowing division of labor through severing or keeping intact their stolon connections. The results showed that stolon connection significantly increased the root mass to shoot mass ratio of basal ramets under low light and high soil nutrient conditions, but greatly decreased it in the apical ramets under high light and low soil nutrient conditions, suggesting induced division of labor in all studied plants. Moreover, the invasive plant A. philoxeroides demonstrated a greater capacity for division of labor than its co-genus and co-occurring native partners, which conferred it with greater growth performance at the whole clonal fragment level. Given that the commonly observed competitive superiority of invasive clonal plants over co-occurring native species due to their high intrinsic growth rates, these findings suggest that the division of labor may confer a competitive advantage upon some invasive clonal plants, thereby facilitating their successful invasion in heterogeneous habitats characterized by a strong negative correlation between light availability and soil nutrient levels.

Cadmium interacts with nitrogen level and nitrogen form to affect the growth of an invasive plant Alternanthera philoxeroides

Cadmium interacts with nitrogen level and nitrogen form to affect the growth of an invasive plant Alternanthera philoxeroides

Effects of 13C isotope-labeled allelochemicals on the growth of the invasive plant Alternantheraphiloxeroides

The secondary metabolites of indigenous plants have significant allelopathic inhibitory effects on the growth and development of invasive alien plants. Methyl palmitate (MP) and methyl linolenate (ML) were used as exogenous allelopathic substances. The research investigated the differences of inhibitory effects of MP and ML on the growth of seedlings of Alternantheraphiloxeroides, and calculated their morphological characteristics, biomass, physiological indicators and the response index (RI). The synthetical allelopathic index (SE) of 1 mmol/L MP was the smallest (− 0.26) and the allelopathic inhibition was the strongest; therefore, it was selected as a 13C-labeled allelochemical. The distribution of 1 mmol/L MP in different parts of A.philoxeroides and the correlation between the biomass ratios of roots, stems and leaves and the 13C content were studied by 13C stable isotope tracing experiments. Atom percent excess (APE) between roots, stems and leaves of A.philoxeroides treated with 1 mmol/L MP were significantly different in terms of magnitude, with leaves (0.17%) > roots (0.12%) > stems (0.07%). The root, stem and leaf biomass ratios of invasive weeds had great significant positive correlation with 13C content (p < 0.01, R2 between 0.96 and 0.99). This current research provides a new idea and method for the control of A.philoxeroides, but large-scale popularization remains to be studied.

Invasive Plant Alternanthera philoxeroides Benefits More Competition Advantage from Rhizosphere Bacteria Regardless of the Host Source.

The rhizosphere plays a vital role in the exchange of materials in the soil-plant ecosystem, and rhizosphere microorganisms are crucial for plant growth and development. In this study, we isolated two strains of Pantoea rhizosphere bacteria separately from invasive Alternanthera philoxeroides and native A. sessilis. We conducted a control experiment to test the effects of these bacteria on the growth and competition of the two plant species using sterile seedlings. Our findings showed that the rhizobacteria strain isolated from A. sessilis significantly promoted the growth of invasive A. philoxeroides in monoculture compared to native A. sessilis. Both strains significantly enhanced the growth and competitiveness of invasive A. philoxeroides under competition conditions, regardless of their host source. Our study suggests that rhizosphere bacteria, including those from different host sources, can contribute to the invasion of A. philoxeroides by significantly enhancing its competitiveness.

Effects of fragmentation, cadmium, and nutrients on the growth of a wetland invasive plant Alternanthera philoxeroides

AbstractFragmentation caused by disturbance is frequent in wetlands and usually co‐occurs with increases in cadmium and nutrient availability. However, whether fragmentation can interact with nutrients and heavy metals to affect wetland invasive plants has been little studied. We conducted a greenhouse experiment to test the effects of fragmentation (initial fragment was non‐severed, was severed into two fragments, and three fragments), cadmium (low, medium, and high), and nutrient availability level (high and low) on the growth of a widespread, invasive clonal plant Alternanthera philoxeroides (Mart.) Griseb. Clonal fragmentation reduced the total mass, stolon mass, root mass, and total stolon length of A. philoxeroides and altered the biomass allocation. Increases in cadmium adversely affected the growth of A. philoxeroides. The high level of cadmium increased leaf mass ratio but decreased stolon mass ratio. Response of leaf mass ratio to fragmentation varied at different cadmium or nutrient availability levels. Fragmentation, cadmium, and nutrients had a significant interaction on leaf mass ratio. Our results suggest that fragmentation can adversely affect the growth of A. philoxeroides. The adverse effect of fragmentation was greater at high nutrient levels and high cadmium levels (0.4 and 2 mg L−1).

Transgenerational Herbivory Effects on Performance of Clonal Offspring of the Invasive Plant Alternanthera philoxeroides

Interactions between alien plants and local enemies in introduced ranges may determine plant invasion success. However, little is known about whether herbivory-induced responses are transmitted across vegetative generations of plants and whether epigenetic changes are involved during this process. In a greenhouse experiment, we examined the effects of herbivory by the generalist herbivore Spodoptera litura on the growth, physiology, biomass allocation and DNA methylation level of the invasive plant Alternanthera philoxeroides in the first- (G1), second- (G2) and third-generation (G3). We also tested the effects of root fragments with different branching orders (i.e., the primary- or secondary-root fragments of taproots) of G1 on offspring performance. Our results showed that G1 herbivory promoted the growth of the plants in G2 that sprouted from the secondary-root fragments of G1 but had a neutral or negative effect on the growth of the plants in G2 from the primary-root fragments. The growth of plants in G3 was significantly reduced by G3 herbivory but not affected by G1 herbivory. Plants in G1 exhibited a higher level of DNA methylation when they were damaged by herbivores than when they were not, while neither plants in G2 nor G3 showed herbivory-induced changes in DNA methylation. Overall, the herbivory-induced growth response within one vegetative generation may represent the rapid acclimatization of A. philoxeroides to the unpredictable generalist herbivores in the introduced ranges. Herbivory-induced trans-generational effects may be transient for clonal offspring of A. philoxeroides, which can be influenced by the branching order of taproots, but be less characterized by DNA methylation.

Parasitism Shifts the Effects of Native Soil Microbes on the Growth of the Invasive Plant Alternanthera philoxeroides.

Soil microbes play an important role in plant invasion, and parasitic plants regulate the growth of invasive plants. However, the mechanisms by which parasitic plants regulate the effects of soil microbes on invasive plants have not been investigated. Here, we used the invasive plant Alternanthera philoxeroides and the holoparasitic plant Cuscuta grovonii to test whether and how C. grovonii parasitism shifts the effect of native soil microbes on the growth of A. philoxeroides. In a factorial setup, A. philoxeroides was grown in pots with the presence versus absence of parasitism and the presence versus absence of native soil microbes. The findings showed that native soil microbes increased the biomass and clonal growth of A. philoxeroides only in the absence of a parasite, whereas parasitism decreased the biomass and clonal growth of A. philoxeroides only in the presence of soil microbes. In addition, the presence of soil microbes increased the deleterious effects of the parasite on A. philoxeroides. These results indicate that parasitism can shift the effects of native soil microbes on the growth of the invasive plant A. philoxeroides. Our results enrich the understanding of the mechanisms underlying the success of plant invasion.

Intra- and Interspecific Competition Altered the Competitive Strategies of Alternanthera philoxeroides and Trifolium regens under Cadmium Contamination

Heavy metal accumulation in soils has been one of the environmental and ecological issues, as it caused life and biodiversity problems. However, many invasive plants can survive in heavy metal polluted areas, but little is known about the invasiveness while under different densities either with native species or themselves. In this study, a greenhouse experiment was performed to examine how cadmium contamination with different concentrations (0, 100, and 200 mg/kg) may influence the interspecific competition between invasive plant Alternanthera philoxeroides and the landscape grass T. regens, as well as the intraspecific competition of A. philoxeroides with different densities. The results showed that stronger interspecific competition would alleviate cadmium damage to both A. philoxeroides and T. regens, but the two species adopted different allocation strategies. A. philoxeroides allocated more biomass to belowground and less to aboveground, while T. regens showed exactly the opposite allocation strategy. There was a significant density effect of intraspecific competition on A. philoxeroides. That is to say, with the increase of A. philoxeroides density, the cadmium stress on the growth of A. philoxeroides decreased. Our findings provide a theoretical basis and technical support for the effective control of A. philoxeroides invasion, as well as the restoration and reconstruction of green vegetation.

Effects of cadmium and nutrients on the growth of the invasive plant Alternanthera philoxeroides

Effects of cadmium and nutrients on the growth of the invasive plant Alternanthera philoxeroides

Latitudinal trends in the structure, similarity and beta diversity of plant communities invaded by Alternanthera philoxeroides in heterogeneous habitats.

Variations in latitudinal gradients could lead to changes in the performance and ecological effects of invasive plants and thus may affect the species composition, distribution and interspecific substitution of native plant communities. However, variations in structure, similarity and beta (β) diversity within invaded communities across latitudinal gradients in heterogeneous habitats remain unclear. In this study, we conducted a two-year field survey along 21°N to 37°N in China, to examine the differential effects of the amphibious invasive plant Alternanthera philoxeroides on native plant communities in terrestrial and aquatic habitats. We compared the differences in the invasion importance value (IV), species distribution, community similarity (Jaccard index and Sorenson index) and β diversity (Bray−Curtis index and βsim index) between terrestrial and aquatic communities invaded by A. philoxeroides, as well as analyzed their latitudinal trends. We found that the IV of A. philoxeroides and β diversity in aquatic habitats were all significantly higher than that of terrestrial, while the terrestrial habitat had a higher community similarity values. The aquatic A. philoxeroides IV increased with increasing latitude, while the terrestrial IV had no significant latitudinal trend. With increasing latitude, the component proportion of cold- and drought-tolerant species in the terrestrial communities increased, and the dominant accompanying species in the aquatic communities gradually changed from hygrophytes and floating plants to emerged and submerged plants. In addition, the aquatic communities had lower community similarity values and higher β diversity in higher latitudinal regions, while terrestrial communities had the opposite parameters in these regions. Our study indicates that the bioresistance capacities of the native communities to invasive A. philoxeroides in heterogeneous habitats are different; A. philoxeroides invasion leads to higher community homogenization in terrestrial habitats than in aquatic habitats, and terrestrial communities experience more severe homogenization in higher latitudinal regions. These findings are crucial for predicting the dynamics of invasive plant communities under rapid global change.

Effects of simulated acid rain on rhizosphere microorganisms of invasive Alternanthera philoxeroides and native Alternanthera sessilis.

Acid rain not only has serious harm to the environment, but also has the same threat to plants, but the invasive plant Alternanthera philoxeroides still grows well compared to the native plant Alternanthera sessilis under acid rain stress. However, the underlying mechanism of resistance to the acid rain environment in invasive Alternanthera philoxeroides remains unclear. In the current study, we comparatively analyzed the plant physiological characteristics, soil physicochemical properties, and rhizosphere microbial communities of invasive A. philoxeroides and native A. sessilis under different pH condition. The simulated acid rain had a significant inhibitory effect on the morphological and physiological traits of A. philoxeroides and A. sessilis and reduced the soil nutrient content. However, A. philoxeroides was more tolerant of acid rain. Compared with CK, simulated acid rain treatment at pH 2.5 significantly increased the Chao1, ACE, and Shannon indexes of A. philoxeroides microorganisms. Under simulated acid rain treatment at pH 2.5, the fungal flora Chao1, ACE and Shannon index were significantly higher than those of CK by 14.5%, 12.4%, and 30.4%, respectively. The dominant bacterial phyla of soil bacteria were Proteobacteria, Actinobacteria, Bacteroidota, Actinobacteria, Firmicutes, Myxococcota, Chloroflexi, Patescibacteria, Gemmatimonadota, Verrucomicrobiota, and Armatimonadota. The dominant fungi were Ascomycota, Basidiomycota, Rozellomycota, and Olpidiomycota. The bacterial and fungal diversity and structure of A. philoxeroides and A. sessilis showed the greatest difference between the pH 2.5 treatment and CK. Redundancy analysis showed that electrical conductivity (EC) and total phosphorus (TP) were the main factors changing the bacterial communities, and available phosphorus (AP), organic matter (OM), EC, and pH were the main factors changing the fungal communities. This study contributes to the microbial community structure of the invasive plant A. philoxeroides and provides a theoretical basis for studying the invasion mechanism of invasive plants under acid rain.

Effects of above- and below-ground herbivore interactions on interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener Alternanthera sessilis

Biological invasion is a major threat to global biodiversity. The relative interspecific competition abilities of invasive species compared to those native species determine their invasion success. In this study, we examined the effects of the specialist leaf beetle Agasicles hygrophila and the nematode Meloidogyne incognita on the growth and interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener A. sessilis. Compared without herbivory, nematode herbivory alone significantly reduced shoot height of A. sessilis by 28.1%, but conversely significantly increased the shoot height of A. philoxeroides by 52.8% and aboveground biomass of A. sessilis by 63.7%. Beetle herbivory alone significantly reduced shoot height of A. sessilis by 40.7%, but did not affect that of A. philoxeroides. The combination of beetle and nematode herbivory significantly reduced shoot height of A. sessilis by 35.3% as well as the belowground biomass of A. philoxeroides by 62.2%, but significantly increased the aboveground biomass of A. sessilis by 69.1%. Herbivore stress did not affect stem diameter, branch number, and root length of both species. The relative neighbor effect index (RNE) of the two species without herbivory were positive, and the RNE value of A. philoxeroides was 21.3% higher than that of A. sessilis. However, the RNE values of A. philoxeroides were negative under all above- and below-ground herbivory treatments. The RNE values of A. sessilis were positive under the beetle or the nematode herbivory alone and negative under the beetle + nematode herbivory combination. These results indicated that above- and below-ground herbivore interactions could change the interspecific relationship between the two species, and in turn might accelerate the invasion of A. philoxeroides.

Latitudinal variation in the diversity and composition of various organisms associated with an exotic plant: the role of climate and plant invasion.

Climate and plant invasion can shape biotic communities at large spatial scales. Yet, how diverse groups of organisms associated with an invasive plant change simultaneously with latitude and the roles of climate and plant invasion remains unclear. We conducted a field survey of plants (native vs exotic), soil fungi (pathogenic, saprotrophic, arbuscular mycorrhiza fungi (AMF) and ectomycorrhizal (EcM) fungi) and arthropods (herbivores, predators and detritivores) associated with the invasive plant Alternanthera philoxeroides at 49 sites spanning 14 latitudinal degrees in China. Results showed that diversity and composition of these functional groups changed differently with latitude, partially due to their specific responses to climate, invasion of A.philoxeroides and other biotic environments. Moreover, A.philoxeroides invasion and/or composition of other plants, rather than climate, predicted the diversity and richness of major functional groups and partly explained variance in composition of putative fungal pathogens. Our results suggest that climate and plant invasion could affect the diversity and composition of diverse groups of organisms simultaneously and their relative importance might vary among functional groups. Thus, it is necessary to explore latitudinal patterns and underlying drivers of diverse groups of organisms simultaneously to improve our ability to predict and mitigate threats posed by plant invasion and climate change.

Combination effects of heavy metal and inter-specific competition on the invasiveness of Alternanthera philoxeroides

Inter-specific competition is an essential factor affecting the invasiveness of alien plants. Although many exotic invasive plants are characterised by a high tolerance to many pollutants, e.g. heavy metals, little is currently known regarding the impact of heavy metals on the interaction between native and invasive plants. In this study, we used the invasive plant Alternanthera philoxeroides (Mart.) Griseb. and its native congener Alternanthera sessilis (L.) R.Br. ex DC to assess their competitive interaction in response to treatments with copper, cadmium, and zinc applied at different concentrations (10, 30, 60, and 100 mg kg−1 for Cd; 200, 400, and 1000 mg kg−1 for Cu; and 500, 1000, and 2000 mg kg−1 for Zn), along with a control treatment. We accordingly found that both invasive and native plants show high tolerance to heavy metals; however, the tolerance index of A. philoxeroides increased significantly from monoculture to mixed culture in response to Cu and Cd treatments. In addition, A. philoxeroides showed greater phenotypic plasticity to culture type than its native congener. Furthermore, the specific leaf area of A. philoxeroides in the mixed culture was found to be higher than that in monoculture. Additionally, in response to Cu and Cd treatments, the biomass of A. philoxeroides in mixed culture was notably shifted from the roots to shoots, in contrast to the control group, the variances in A. philoxeroides responses in monoculture were less perceptible. We speculate that such high phenotypic plasticity may represent an important tolerance strategy for invasive plants that can enhance their competitive ability against native plants under conditions of heavy metal stress, and consequently a combination of heavy metal stress and inter-specific competition would be conducive to the invasiveness of A. philoxeroides, particularly in habitats characterised by high levels of heavy metal pollution.

The decomposition process and nutrient release of invasive plant litter regulated by nutrient enrichment and water level change.

Wetlands are vulnerable to plant invasions and the decomposition of invasive plant litter could make impacts on the ecosystem services of wetlands including nutrient cycle and carbon sequestration. However, few studies have explored the effects of nutrient enrichment and water level change on the decomposition of invasive plant litter. In this study, we conducted a control experiment using the litterbag method to compare the decomposition rates and nutrient release in the litter of an invasive plant Alternanthera philoxeroides in three water levels and two nutrient enrichment treatments. This study found that the water level change and nutrient enrichment showed significant effects on the litter decomposition and nutrient dynamic of A. philoxeroides. The increase of water level significantly reduced the decomposition rate and nutrient release of litter in the nutrient control treatment, whereas no clear relationship was observed in the nutrient enrichment treatment, indicating that the effect of water level change on litter decomposition might be affected by nutrient enrichment. At the late stage of decomposition, the increase of phosphorus (P) concentration and the decrease of the ratio of carbon to P suggested that the decomposition of invasive plant litter was limited by P. Our results suggest that controlling P enrichment in water bodies is essential for the management of invasive plant and carbon sequestration of wetlands. In addition, the new index we proposed could provide a basis for quantifying the impact of invasive plant litter decomposition on carbon cycle in wetlands.

Effects of elevated temperature on chemistry of an invasive plant, its native congener and their herbivores

AbstractClimatic warming affects plant growth and physiology, yet how warming alters chemistry in invasive plants and indirectly affects herbivorous insects remains largely unknown. Here, we explored warming-induced changes in leaf chemistry of the invasive plant Alternanthera philoxeroides and its native congener Alternanthera sessilis, and further examined how these changes affected the performance of the herbivores, Cassida piperata and Spodoptera litura. We conducted a simulated warming experiment to address its effects on 13 leaf chemical traits of A. philoxeroides and A. sessilis. We measured growth and development time of two herbivores reared on plants from warming or ambient controls. Warming significantly affected leaf chemistry composition for both the invasive and native Alternanthera. Warming decreased nitrogen concentration in A. philoxeroides and increased total flavonoid and total phenol concentration in A. sessilis. The effects of warming on nutrients (i.e. fructose, sucrose, total soluble sugar and starch) varied with individual chemicals and plant species. Weight of C. piperata pupal and S. litura larval reared on warming-treated A. sessilis significantly decreased compared with non-warmed control, and a similar pattern was observed for weight of S. litura larval feeding on warming-treated A. philoxeroides. In addition, warming-treated A. sessilis significantly prolonged larval development time of S. litura. These results indicate that warming can directly affect the leaf chemistry in both invasive plant and its native congener, but these effects vary by species. Such differences in warming-induced changes in plant chemistry could indirectly affect herbivorous insects associated with the invasive and native plants.

Phenotypic plasticity in resource allocation to sexual trait of alligatorweed in wetland and terrestrial habitats

Environmental heterogeneity in resource availability affects invasive plant reproductive strategies and resource allocation to reproduction. Here, we conducted two field surveys to examine the effect of wetland and terrestrial habitats on inflorescence production and resource allocation to inflorescence of the amphibious invasive plant Alternanthera philoxeroides in its invasive range (China). We also specifically examined the effects of water availability, fertilizer application, and plant density (space) in a greenhouse experiment. In field surveys, inflorescence biomass, normal monoclinous flowers and ratio of inflorescences to shoots of plants from wetlands were about 2.4-, 0.8- and 1.3-fold higher than those from terrestrial habitats, respectively. In greenhouse experiment, plants with higher fertilizer application and lower competition conditions produced more inflorescences, and had a lower ratio of roots to shoots and a comparable ratio of inflorescences to shoot and root. Furthermore, water availability had a significant interactive effect when combined with fertilizer level or plant density on inflorescence production and resource allocation. Together, our results indicate that high resources, such as those found in wetland habitats, favor both vegetative growth and sexual trait in A. philoxeroides. However, in terrestrial habitats where resources are relatively poor, the invader can adapt to the environment by allocating more resources to vegetative growth for clonal reproduction and less resources for sexual trait. This phenotypic plasticity in resource allocation likely facilitates the plant to invade heterogeneous wetlands and terrestrial environments.

An invasive plant rapidly increased the similarity of soil fungal pathogen communities.

Plant invasions can change soil microbial communities and affect subsequent invasions directly or indirectly via foliar herbivory. It has been proposed that invaders promote uniform biotic communities that displace diverse, spatially variable communities (the biotic homogenization hypothesis), but this has not been experimentally tested for soil microbial communities, so the underlying mechanisms and dynamics are unclear. Here, we compared density-dependent impacts of the invasive plant Alternanthera philoxeroides and its native congener A. sessilis on soil fungal communities, and their feedback effects on plants and a foliar beetle. We conducted a plant-soil feedback (PSF) experiment and a laboratory bioassay to examine PSFs associated with the native and invasive plants and a beetle feeding on them. We also characterized the soil fungal community using high-throughput sequencing. We found locally differentiated soil fungal pathogen assemblages associated with high densities of the native plant A. sessilis but little variation in those associated with the invasive congener A. philoxeroides, regardless of plant density. In contrast, arbuscular mycorrhizal fungal assemblages associated with high densities of the invasive plant were more variable. Soil biota decreased plant shoot mass but their effect was weak for the invasive plant growing in native plant-conditioned soils. PSFs increased the larval biomass of a beetle reared on leaves of the native plant only. Moreover, PSFs on plant shoot and root mass and beetle mass were predicted by different pathogen taxa in a plant species-specific manner. Our results suggest that plant invasions can rapidly increase the similarity of soil pathogen assemblages even at low plant densities, leading to taxonomically and functionally homogeneous soil communities that may limit negative soil effects on invasive plants.

Allelopathic effects of water extracts from sweet potato on the growth of invasive alien species Alternanthera philoxeroides

It is an effective approach to control invasive plants based on the allelopathic effect of native plants with higher economic values, from the perspective of allelopathy. The aim of this study was to test the allelopathic effect of a local crop, sweet potato (Ipomoea batatas), on the invasive plant Alternanthera philoxeroides. Water extracts from different organs of sweet potato (roots, stems, leaves) with three concentrations (0.025, 0.05, 0.1 g·mL-1) were used in the study. To test the effect of sweet potato on rhizome growth of A. philoxeroides, the morphological index (ramet number, node number, leaf number, leaf area, plant height, total dry weight and root number of new ramets), allelopathic response index, trait values (succulent degree, root-shoot ratio, specific leaf area, leaf mass ratio, stem mass ratio, root mass ratio), CAT, POD, MDA and SOD in young leaves were measured. The results showed that 1) Water extracts from different organs of sweet potato with different concentrations differed in their effects on the growth of A. philoxeroides. Water extract from root with 0.1 g·mL-1 significantly inhibited all morphological indices. Except total dry weight and root number, other morphological indices decreased significantly with increasing concentration of water extract from all organs. 2) The synthetic allelopathic response index (RI) was negative under all treatments, indicating that water extract of sweet potato had negative effects on all indices of A. philoxeroides and thus inhibited their growth. Among all the treatments, water extract from root with a concentration of 0.1 g·mL-1 had the strongest allelopathic inhibition (RI=-0.73), followed by that from stem with a concentration of 0.1 g·mL-1(RI=-0.44) and from root with a concentration of 0.05 g·mL-1(RI=-0.44). 3) Water extract of sweet potato had significant inhibitory effects on the degree of succulence, root-shoot ratio, specific leaf area, and leaf mass ratio, but did not affect stem mass ratio and root mass ratio. 4) Water extract of sweet potato significantly increased the contents of MDA and SOD in the fresh leaves of A. philoxeroides, while had no effect on the contents of CAT and POD. All these results indicates that water extract of sweet potato significantly suppress the ramet growth of A. philoxeroides.

Safety evaluation and ibuprofen removal via an Alternanthera philoxeroides-based biochar

Pharmaceutical and personal care products (PPCPs) are a representative class of emerging contaminants. This study aimed to investigate the PPCP removal performance and application safety of a biochar fabricated using the invasive plant Alternanthera philoxeroides (APBC). According to scanning electron microscopy and pore size analyses, APBC exhibited a porous structure with a specific surface area of 857.5m2/g. A Fourier transform infrared spectroscopy analysis indicated the presence of surface functional groups, including phosphorus-containing groups, C=O, C=C, and -OH. The adsorption experiment showed that the maximum removal efficiency of ibuprofen was 97% at an initial concentration of 10mg/L and APBC dosage of 0.8g/L. The adsorption kinetics were fitted by the pseudo-second-order model with the highest correlation coefficient (R2 = 0.9999). The adsorption isotherms were well described by the Freundlich model (R2 = 0.9896), which indicates a dominant multilayer adsorption. The maximum adsorption capacity of APBC was 172mg/g. A toxicity evaluation, based on Chlorella pyrenoidosa and human epidermal BEAS-2B cells, was carried out using a spectrum analysis, thiazolyl blue tetrazolium bromide assay, and flow cytometry. The results of the above showed the low cytotoxicity of APBC and demonstrated its low toxicity in potential environmental applications.