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The proliferation of alien species that can suppress resident species via biotic interactions represents a growing concern worldwide. Yet, how above‐ and below‐ground communities simultaneously respond to plant invasion, particularly across large spatial scales, remains poorly explored. We hypothesized plant invasion has a greater impact on recipient above‐ and below‐ground communities at lower than higher latitudes given that biotic interactions play a more significant role in shaping communities in more favourable, lower latitude environments.To test this hypothesis, we conducted a comprehensive field survey of 124 sites spanning a 1700‐km latitudinal gradient in China, to explore the effects of invasion of Alternanthera philoxeroides, a globally widespread invasive plant, on plant, soil fungal and above‐ground arthropod communities.Invasion of A. philoxeroides had divergent effects on beta diversity (i.e. variation in taxa composition among sites) of plants, above‐ground arthropods and soil saprotrophic fungi, with negative, neutral and positive responses, respectively. Notably, the compositional dissimilarity of plant and arthropod communities between adjacent invaded and non‐invaded sites remained constant across latitudes. In contrast, the compositional dissimilarity of the entire and pathogenic fungal communities between adjacent invaded and non‐invaded sites increased with latitude. This resulted in a decreasing difference in invasion effects on the composition of plant and fungal communities with increasing latitude.Synthesis. Our study provides novel insights into the complexities of invasion effects by revealing contrasting responses of above‐ and below‐ground communities to plant invasion across latitudes. The contrasting responses could weaken or reshape above‐ and below‐ground interactions, and, in turn, affect future species invasions and the functioning of terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Forest litter can decompose faster at home sites than at guest sites (home-field advantage, HFA), yet few studies have focused on the response of the HFA of native plant decomposition to the presence of invasive plants. We loaded the dry leaves of native Neosinocalamus affinis (decomposition resistant) and Ficus virens (more easily decomposable) leaves into litterbags with and without invasive Alternanthera philoxeroides, and incubated these litterbags at N. affinis and F. virens sites at the edge of the forest. The results showed that positive HFA effects with litter mass loss were at least 1.32% faster at home sites than at guest sites. The addition of A. philoxeroides reduced the mean HFA of N. affinis litter and increased that of F. virens litter. The HFA index without A. philoxeroides was significantly higher than that with A. philoxeroides. Soil faunal abundance colonized at home sites was always higher than that colonized at guest sites. Compared with the F. virens site, the abundance of Collembola, Arachnida, Formicidae and Lepismatidae at the N. affinis site was significantly higher compared to the F. virens site, while the abundance of Isopoda, Oligochaeta, Nematoda and Dermaptera was significantly lower. Our results indicate that invasive plants may regulate HFA effects by promoting the decomposition of native plants and increasing fauna abundance. Particularly, soil fauna groups play a very important role in this process. Our findings help us to re-understand the role of invasive plants in material cycling and energy flow in the context of achieving carbon neutrality goals. [ABSTRACT FROM AUTHOR]

Alligator weed (Alternanthera philoxeroides) is a highly invasive species that has successfully established in numerous tropical and subtropical regions worldwide. Previous literature suggests that alligator weed was introduced to China in the 1930s as fodder for military horses by Japanese, while its presence in Japan only became apparent in the 1990s. Consequently, the introduction and genetic relationship between alligator weed populations in China and Japan remain uncertain, and the native source population is still unidentified. This study aimed to characterize the genetic diversity and structure of populations within the introduced range of China and Japan, as well as the native range of Argentina, using amplified fragment length polymorphism (AFLP) markers. Nine primer pairs were employed, resulting in a total of 573 distinct amplified bands for the China and Japan populations. However, none of these bands displayed polymorphism, indicating a uniform genetic background across all sampled populations in China and Japan. In contrast, the Argentine populations yielded 251 identifiable amplified bands using four well-performing primer pairs, of which 209 (80.69%) were found to be polymorphic. Genetic relationship and population structure analyses based on AFLP data revealed that the population from Jujuy, Argentina, exhibited the closest genetic affinity to the invasive populations in China and Japan, as indicated by Nei's genetic identity value of 0.9281. Additionally, using methylation-sensitive amplified polymorphism (MSAP), we identified 258 epigenetic variation sites using five primer pairs in the Chinese and Japanese populations. Principal coordinate analysis (PCoA) based on the MSAP data revealed a geographic epigenetic structure within the alligator weed populations of China and Japan, with DNA methylation variation patterns exhibiting correlation with geographic distribution, thus implying their potential involvement in environmental adaptation. This research enhances our understanding of the invasion mechanisms of alligator weed and provides valuable insights into the roles of epigenetic factors in its successful spread. [ABSTRACT FROM AUTHOR]

Alternanthera philoxeroides (Amaranthaceae), commonly known as alligator weed, is a globally invasive and detrimental perennial weed. Agasicles hygrophila serves as an important biocontrol agent for alligator weeds. However, during mid-summer, when temperatures increase, A. hygrophila populations experience a significant decline, leading to ineffective weed control. This study has examined the impact of periodic heat events on the reproduction and survival of A. hygrophila females and males using various mating combinations and durations of temperature treatments. The results demonstrated significant effects on all of the studied parameters across mating combinations when compared with the control. Under the same temperature combination, the fecundity and survival rates of females, as well as the egg-hatching rate, decreased significantly with increasing repeated heat exposure. Furthermore, the egg-hatching rate varied significantly among different temperatures and time-interval combinations. In addition, the females displayed greater sensitivity to heat stress than males in terms of fecundity. These findings enhance our understanding of A. hygrophila population dynamics during summer and provide insights into the release of biocontrol agents in diverse regions with varying climates. [ABSTRACT FROM AUTHOR]

Invasive plants have been shown to alter ecosystem functions. However, there is limited information available on the effect of the invasive species litter input on native litter decomposition and home-field advantage (HFA, increased decomposition at a home environment compared to a guest environment). To investigate this, we conducted a field experiment using leaves of native Trapa natans and Typha orientalis with and without invasive species Alternanthera philoxeroides and then incubated them at T. natans and T. orientalis habitats in a eutrophic lake for 50 days. In control and treatment, the decomposition and N release rate of T. natans were significantly higher than that in T. orientalis species litter at two habitats, indicating no HFA occurrence. A. philoxeroides litter input promoted the decomposition and N decay rate of T. orientalis, not T. natans. The mean decomposition rate of T. orientalis in control and treatment were 0.0138 and 0.0342 day−1; for T. natans, it was 0.0703 and 0.0754 day−1, respectively. The mean N decay rate of T. orientalis in control and treatment were 0.0235 and 0.0468 day−1; for T. natans, it was 0.0511 and 0.0544 day−1, respectively. Invasive species presence increased microbial respiration rate of T. orientalis, but not for T. natans species litter in two habitats. These results suggested that A. philoxeroides litter input accelerated low quality litter decomposition though increased microbial activity. However, it did not influence the HFA performance, which may be closely related to the lake eutrophication. [ABSTRACT FROM AUTHOR]

Both heavy metal pollution and plant invasion are serious global environmental problems. Nutrient availability has been shown to influence the performance of invasive plants in heavy metal polluted environments. However, it is still unclear whether the effects of nutrients differ between different forms. We conducted a greenhouse experiment to test the effects of cadmium (0.5, 1 and 2 mg L−1) and nitrogen concentration (0.5, 2 and 8 mmol L−1) as well as nitrogen form (ammonia nitrogen, nitrate nitrogen and glycine) on the invasive, widespread plant Alternanthera philoxeroides. Cadmium did not affect the overall growth of Alternanthera philoxeroides. In the presence of cadmium, plants grew better when provided with nitrate nitrogen than with ammonia nitrogen or glycine. Cadmium interacted with nitrogen level and nitrogen form to affect the growth. At medium (1 mg L−1) and high (2 mg L−1) cadmium levels, promotion of high level nitrate nitrogen (8 mmol L−1) on plant growth was significantly reduced. Our results suggest that the growth performance of Alternanthera philoxeroides in cadmium polluted water is related to both nitrogen level and form. These findings could provide a basis for predicting the spread of Alternanthera philoxeroides in polluted water. [ABSTRACT FROM AUTHOR]

Invasive plants are often attacked by both introduced specialist and native generalist natural enemies in new ranges. Soil fertility can potentially alter the interactions of these natural enemies with native versus invasive plants in ways that have largely unexplored implications for biological invasions and biological control.A common garden experiment was conducted to compare the performance of an introduced specialist flea beetle, Agasicles hygrophila, and/or a native generalist nematode, Meloidogyne incognita, on invasive alligator weed, Alternanthera philoxeroides, and its native congener sessile joyweed, Alternanthera sessilis, under different levels of soil nitrogen (N) and phosphorus (P).At a relatively low or moderate N and P levels, the flea beetle and the nematodes were not significantly affected by each other. Under these conditions, alligator weed responded plastically by producing more branches and biomass, as well as longer stolons, in response to attack by the flea beetle and/or the nematode, compared to sessile joyweed responses to similar levels of damage. However, under a relatively high N and P levels, nematode infestations significantly reduced flea beetle damage on alligator weed, resulting in significantly greater above‐ and below‐ground biomass and longer stolons than plants without herbivory. In contrast, beetle herbivory significantly increased the level of nematode infestations on sessile joyweed, resulting in significantly fewer fine and coarse roots, and lower above‐ and below‐ground biomass compared to plants without herbivory.Synthesis and applications. Our findings illustrate the importance of soil fertility in mediating interactions between specialist biocontrol agents and native generalists on native versus invasive plants. High phenotypic plasticity seems to be an important attribute that contributes to the success of invasive plants like alligator weed in relatively nutrient‐poor environments. However, nutrient‐rich environments could potentially confer greater growth benefits on invasive plants than on native ones by changing herbivore–herbivore interactions on plants differently. There is a great need to fully investigate the direct and indirect interactions between biocontrol agents and generalists across food webs following classical biocontrol releases. Nutrient measurements of both soil and water bodies should also be incorporated into all stages of biocontrol programmes. [ABSTRACT FROM AUTHOR]

Alternanthera sessilis is considered the closest relative to the invasive weed Alternanthera philoxeroides in China, making it an important native species for studying the invasive mechanisms and adaptations of A. philoxeroides. Chloroplasts play a crucial role in a plant's environmental adaptation, with their genomes being pivotal in the evolution and adaptation of both invasive and related species. However, the chloroplast genome of A. sessilis has remained unknown until now. In this study, we sequenced and assembled the complete chloroplast genome of A. sessilis using high-throughput sequencing. The A. sessilis chloroplast genome is 151,935 base pairs long, comprising two inverted repeat regions, a large single copy region, and a small single copy region. This chloroplast genome contains 128 genes, including 8 rRNA-coding genes, 37 tRNA-coding genes, 4 pseudogenes, and 83 protein-coding genes. When compared to the chloroplast genome of the invasive weed A. philoxeroides and other Amaranthaceae species, we observed significant variations in the ccsA, ycf1, and ycf2 regions in the A. sessilis chloroplast genome. Moreover, two genes, ccsA and accD, were found to be undergoing rapid evolution due to positive selection pressure. The phylogenetic trees were constructed for the Amaranthaceae family, estimating the time of independent species formation between A. philoxeroides and A. sessilis to be approximately 3.5186–8.8242 million years ago. These findings provide a foundation for understanding the population variation within invasive species among the Alternanthera genus. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil properties can affect plant population dynamics and the coexistence of native and invasive plants, thus potentially affecting community structure and invasion trends. However, the different impacts of soil physicochemical properties on species diversity and structure in native and invaded plant communities remain unclear. In this study, we established a total of 30 Alternanthera philoxeroides-invaded plots and 30 control plots in an area at the geographical boundary between North and South China. We compared the differences in species composition between the invaded and native plant communities, and we then used the methods of regression analysis, redundancy analysis (RDA), and canonical correspondence analysis (CCA) to examine the impacts of soil physicochemical properties on four α-diversity indices and the species distribution of these two types of communities. We found that A. philoxeroides invasion increased the difference between the importance values of dominant plant species, and the invasion coverage had a negative relationship with the soil-available potassium (R2 = 0.135; p = 0.046) and Patrick richness index (R2 = 0.322; p < 0.001). In the native communities, the species diversity was determined with soil chemical properties, the Patrick richness index, the Simpson dominance index, and the Shannon–Wiener diversity index, which all decreased with the increase in soil pH value, available potassium, organic matter, and ammonium nitrogen. However, in the invaded communities, the species diversity was determined by soil physical properties; the Pielou evenness index increased with increasing non-capillary porosity but decreased with increasing capillary porosity. The determinants of species distribution in the native communities were soil porosity and nitrate nitrogen, while the determinants in the invaded communities were soil bulk density and available potassium. In addition, compared with the native communities, the clustering degree of species distribution in the invaded communities intensified. Our study indicates that species diversity and distribution have significant heterogeneous responses to soil physicochemical properties between A. philoxeroides-invaded and native plant communities. Thus, we need to intensify the monitoring of soil properties in invaded habitats and conduct biotic replacement strategies based on the heterogeneous responses of native and invaded communities to effectively prevent the biotic homogenization that is caused by plant invasions under environmental changes. [ABSTRACT FROM AUTHOR]

Odorant binding protein(OBP) is an important protein in the process of insect olfactory communication. OBPs are involved in the first step of insect odor recognition, and play an important role in insect activities such as foraging, aggregation, courtship, and looking for spawning places. In order to determine the expression characteristics of OBP genes in Agasicles hygrophila and to preliminarily understand its functions, in this study, three OBP genes were cloned and analyzed using bioinformatics. The relative expression levels of OBPs in different tissues were analyzed by quantitative real-time PCR. The results showed that the open reading frame of AhygOBP27, AhygOBP32, and AhygOBP44 were 351, 408, 423 bp, respectively. The proteins encoded by the three OBPs were acidic soluble proteins with small molecular weight. AhygOBP27 was mainly expressed in the antennae, head, feet and wings of both sexes. AhygOBP32 was expressed in antennae, head, leg and wings of the male and in antennae, feet and wings of the female. AhygOBP44 was expressed in the antennae, heads and feet of both sexes. The expression levels of above three genes in the antennae of male and female were significantly higher than that of other tissues. The expression level of AhygOBP27 and AhygOBP44 in female antennae were significantly higher than that in male antennae, and the expression level of AhygOBP32 in the antennae of males was significantly higher than that of females. The three genes might play an important role in the olfactory recognition of Agasicles hygrophila, AhypOBP27, and AhygOBP44 might be related to the recognition of host plant volatiles and the search for spawning ground; AhygOBP32 might be involved in the recognition of sex pheromone emitted by females. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to examine the effects of enhanced UV-B radiation, nitrogen addition and their interaction on the interspecific competition between invasive weed Alternanthera philoxeroides and its native accompanying species Digitaria sanguinalis, providing reference for the control of invasive plants under the global change.【Method】According to the de Wit substitution test method, we totally set two experimental factors that contained the treatment method（nitrogen addition, UV-B radiation, nitrogen × UV-B） and the species（A. philoxeroides, D. sanguinalis） on the mono and mixed potting cultures, measured the total biomass, morphology, pigment, and photosynthetic fluorescence of these two studied plant species, and then used the two-way ANOVA and the least significant difference（LSD） multiple comparisons to examine the differences of above indicators with different treatment combinations.【Result】（i） In the monoculture, nitrogen addition led to a significant increase in the maximum stem length of plants and leaf area of D. sanguinalis by 207.154% and 297.643%, and a significant decrease in the total biomass and qp＿Lss of A. philoxeroides by 40.612% and 52.381%, respectively. UV-B radiation led to a significant increase in the maximum stem length of plants, QY＿max and QY＿Lss of A. philoxeroides by 117.607%, 404.459% and 835.714%, respectively, and a significant decrease in the QY＿Lss of D. sanguinalis by 45.605%. The interaction effect led to a significant decrease in the total biomass of A. philoxeroides and QY＿max of D. sanguinalis by 79.310% and 18.984%, and a significant increase in the QY＿max of A. philoxeroides by 685.350%, respectively. The interaction effect also led to an opposite trade-off of F0 and QY＿Lss between these two studied plant species.（ii） In the mixed culture, nitrogen addition led to a significant increase in the leaf area and Chla of D. sanguinalis by 254.259% and 53.018%, respectively, and a significant decrease in the root length and Chla of A. philoxeroides by 76.051% and 12.084%, respectively. UV-B radiation led to a significant increase in the Chla of A. philoxeroides by 45.434%. The interaction effect led to a significant decrease in the root length of A. philoxeroides by 58.824%. 【Conclusion】Nitrogen addition relatively increased the competitive advantage of D. sanguinalis in terms of biomass and morphology, but UV-B radiation weakened its photosynthetic activity and increased the chlorophyll content of A. philoxeroides. Furthermore, UV-B radiation and its interaction with nitrogen addition significantly increased the actual photochemical efficiency of A. philoxeroides. Thus, we should strengthen the monitoring of A. philoxeroides invasion under global change, to prevent the interaction of multiple factors aggravating the competitive substitution of native plants by this invader. [ABSTRACT FROM AUTHOR]

Aging is a well-known factor that accelerates brain deterioration, resulting in impaired learning and memory functions. This current study evaluated the potential of an extract of Alternanthera philoxeroides (AP), an edible flavonoid-rich plant, to ameliorate D-galactose-induced brain aging in male mice. Chronic administration of D-galactose (150 mg/kg/day) in mice mimicked the characteristics of aging by accelerating senescence via downregulation of the following telomere-regulating factors: mouse telomerase reverse transcriptase (mTERT) and mouse telomeric repeat-binding factors 1 (mTRF1) and 2 (mTRF2). D-galactose also decreased the activities of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), while increasing expression of neuroinflammatory cytokines in the frontal cortex and hippocampus. Daily treatment of D-galactose-induced aging mice with AP at 250 and 500 mg/kg/day or vitamin E (100 mg/kg/day) significantly increased the activities of SOD and CAT, as well as expression of mTERT, mTRF1, and mTRF2, which are involved in telomere stabilization, but decreased the levels of proinflammatory cytokines IL-1β, IL-6, and TNF-α. In the behavioral portion of the study, AP improved aging-related cognitive deficits in short-term memory as shown by the Y-maze task and the novel object recognition test (NORT) and long-term memory as shown by the Morris water maze test (MWMT). The flavones kaempferol-O-glucoside (1), quercetin (2), alternanthin B (3), demethyltorosaflavone D (4), and chrysoeriol-7-O-rhamnoside (5), which could be responsible for the observed effects of AP in the D-galactose-induced aging mice, were identified by HPLC analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ecological niche models of species occurrence have gained interest in biological control programs to improve efficiency, reduce risks, and to inform when and how control agents may be released and/or surveyed. Alligator weed, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), is an amphibious aquatic plant native to southern South America that has invaded several countries around the world. In this study, our aim was to quantify the current and to model the future alligator weed geographical distributions in its native range in South America, and in its introduced range (USA, the country where biological control of the weed was first implemented). Additionally, we modelled the current and potential distribution of its biocontrol agent Agasicles hygrophila Selman & Vogt (Coleoptera: Chrysomelidae), released in the USA in 1964, and other potential biocontrol agents, including the flea beetles Disonycha argentinensis Jacoby and Systena sp. In total, 19438 occurrence records of alligator weed, 253 of A. hygrophila, 48 of D. argentinesis, and 19 of Systena sp. were compiled. Niche models predicted expanded distributions of alligator weed, particularly in northern regions of South America. However, the models of the flea beetles A. hygrophila, D. argentinensis, and Systena sp. did not predict geographic range expansion and the future scenarios are similar to current distributions. Our study predicts an increase in the suitable areas for alligator weed in South America in future scenarios of global warming, whereas these new areas would not be as favourable for the biocontrol agents historically used. [ABSTRACT FROM AUTHOR]

Lack of successful biological control of alligatorweed, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), by Agasicles hygrophila Selman & Vogt (Coleoptera: Chrysomelidae) in the USA is an emerging problem as A. philoxeroides expands into temperate climates due to poor cold tolerance of the beetles. Sourcing climatically suited biotypes of biological control agents is traditionally done through foreign exploration into their native range; however, surveying introduced populations may provide a cost‐effective and regulatory‐friendly alternative. To compare foreign biotypes to those established in the USA, two populations of A. hygrophila were collected from the coolest extent of their range in South America, and two populations were collected from stable populations in the southeastern USA. For comparing cold tolerance among introduced populations, eight populations were collected from across a climatic gradient. For all populations, cold tolerance was measured as a function of supercooling point, critical thermal minimum (CTmin), chill coma, and temperature‐dependent survival and development of eggs and larvae. Results of cold‐tolerance measures for North American populations were subjected to principal component analysis (PCA) to reduce dimensionality and detect trends in cold tolerance among populations. For foreign and locally collected A. hygrophila, South American populations were significantly more cold tolerant as measured by CTmin (Δ1.98 °C), chill coma (Δ1.95 °C), larval survival (Δ35.0%), and development time of eggs (24.7% faster) and larvae (17.4% faster) at 15 °C. Comparisons among North American populations found significant differences in cold tolerance across populations; however, results were less consistent than those observed for foreign populations. The first principal component (PC) explained 43.0% of variation in cold‐tolerance metrics and was strongly related to mean temperature of the coldest quarter. The use of a multivariate approach to evaluate and compare cold‐tolerance phenotypes provides strong evidence of local adaptation in introduced populations of A. hygrophila. However, South American populations may still provide the best chance for control of A. philoxeroides in northern infestations. [ABSTRACT FROM AUTHOR]

The presence of macrophytes such as Alternanthera philoxeroides and Eichhornia crassipes in Bellandur Lake, India, has been observed despite the high pollution levels. Our research aims to explore the potential role of endophytes in promoting the growth of these macrophytes in such heavily contaminated environments. In current study, we isolated 20 endophytic bacteria from various parts of A. philoxeroides (12) and E. crassipes (8) plants, including shoots, roots, leaves, and flowers. We found that a significant proportion of endophytes from A. philoxeroides (42 %) and E. crassipes (25 %) produced more than 100 µg/mL of indole acetic acid (IAA). Similarly, the majority of the isolates possessed other plant growth promoting traits like ammonia production, nitrogen fixation, phosphate and potassium solubilization, siderophore production, and ACC deaminase production. Many of these isolates demonstrated extracellular enzyme production and halotolerance properties. We identified Acinetobacter soli ON529869 and Bacillus licheniformis ON506048 as the most effective plant growth promoters among the isolates, which also displayed antifungal properties against Fusarium solani and Cladosporium tenuissimum in vitro. Furthermore, greenhouse trials using these two endophytes revealed their significant plant growth promotion abilities in Amaranthus viridis. The pigment indices were evaluated using CI-710 Leaf Spectrometer. In conclusion, our findings provide compelling evidence for exploring the endophytic microbiomes of macrophytes in polluted areas for sustainable agriculture and bioprospecting of unique traits. This research could lead to the discovery of new and valuable resources for agricultural practices and other applications. [Display omitted] • 20 PGP endophytes isolated from Alternanthera philoxeroides & Eichhornia crassipes. • Acinetobacter soli & Bacillus licheniformis had antifungal effect on Fusarium solani & Conopeum tenuissimum. • A. soli exhibited biosurfactant production. • Greenhouse tests on Amaranthus viridis confirmed their growth-promoting properties. • CI-710 spectrometer showed enhanced plant photosynthesis in treated plants. [ABSTRACT FROM AUTHOR]

We investigated the allelopathic effects of A. philoxeroides stem on E. crassipes and found reduction in plant height (32 to 61 %), number of leaves (13 to 38 %), number of branches (20 to 43%) and fresh weight (63 to 73 %). The E. crassipes plants got dried in cisterns treated with A. philoxeroides. The allelochemicals present in A. philoxeroides plants were inhibitory to water hyacinth. The allelopathic leachate of A. philoxeroides caused maximum decrease in growth of E. crassipes, due to presence of alkaloids and phenols. In control, there were no detrimental effects on growth of E. crassipes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Ocean University is the property of Journal of Dalian Ocean University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil properties can affect plant population dynamics and the coexistence of native and invasive plants, thus potentially affecting community structure and invasion trends. However, the different impacts of soil physicochemical properties on species diversity and structure in native and invaded plant communities remain unclear. In this study, we established a total of 30 Alternanthera philoxeroides-invaded plots and 30 control plots in an area at the geographical boundary between North and South China. We compared the differences in species composition between the invaded and native plant communities, and we then used the methods of regression analysis, redundancy analysis (RDA), and canonical correspondence analysis (CCA) to examine the impacts of soil physicochemical properties on four α-diversity indices and the species distribution of these two types of communities. We found that A. philoxeroides invasion increased the difference between the importance values of dominant plant species, and the invasion coverage had a negative relationship with the soil-available potassium (R2 = 0.135; p = 0.046) and Patrick richness index (R2 = 0.322; p < 0.001). In the native communities, the species diversity was determined with soil chemical properties, the Patrick richness index, the Simpson dominance index, and the Shannon–Wiener diversity index, which all decreased with the increase in soil pH value, available potassium, organic matter, and ammonium nitrogen. However, in the invaded communities, the species diversity was determined by soil physical properties; the Pielou evenness index increased with increasing non-capillary porosity but decreased with increasing capillary porosity. The determinants of species distribution in the native communities were soil porosity and nitrate nitrogen, while the determinants in the invaded communities were soil bulk density and available potassium. In addition, compared with the native communities, the clustering degree of species distribution in the invaded communities intensified. Our study indicates that species diversity and distribution have significant heterogeneous responses to soil physicochemical properties between A. philoxeroides-invaded and native plant communities. Thus, we need to intensify the monitoring of soil properties in invaded habitats and conduct biotic replacement strategies based on the heterogeneous responses of native and invaded communities to effectively prevent the biotic homogenization that is caused by plant invasions under environmental changes.

Alternanthera philoxeroides (AP) is a typical invasive plant. The quick spread of AP biomass may cause serious threat to ecological balance and biodiversity of the local area. However, AP has a high content of potassium, making it possible for preparing biochar through a self-activation process. In this study, AP biomass was employed to prepare porous carbon through a simple one-step pyrolysis. The effect of pyrolysis temperature (T) and carrier gas flow rate (v) onto the target carbon was intensively discussed. The obtained carbon were employed as adsorbents for methylene blue (MB) adsorption. Results showed that both of the T and v played great influence on the porous structure of the obtained biochar. Higher pyrolysis temperature and lower carrier gas flow rate were in favor of the formation of micropore and mesopore. The biochar obtained from 900°C pyrolysis temperature and 20 cm3 min−1 carrier gas flow rate (BC/900–20) possessed a satisfying specific surface area (825.6 m2 g−1) through the direct one-step pyrolysis, verifying the existence of pyrolysis gas self-activation and inorganic salt template self-activation effect. The maximum adsorption capacities calculated from Langmuir model were 424.9 mg g−1 for BC/900–20, which was comparable to that of the adsorbents reported recently. [ABSTRACT FROM AUTHOR]

Fragmentation 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). [ABSTRACT FROM AUTHOR]

Different connected parts of clonal plants often grow in different patches and the resource contrast between patches has an important effect on the material transfer between the connected ramets. However, it is unclear whether the effect of clonal integration differs between the invasive clonal plant and the related native species in response to patch contrast. To explore this, we grew the clonal fragment pairs of plant invader Alternanthera philoxeroides and its co-genus native species A. sessilis under high contrast, low contrast, and no contrast (control) nutrient patch environments, respectively, and with stolon connections either severed or kept intact. The results showed that, at the ramet level, clonal integration (stolon connection) significantly improved the growth of apical ramets of both species, and such positive effects were significantly greater in A. philoxeroides than in A. sessilis. Moreover, clonal integration greatly increased the chlorophyll content index of apical ramets and the growth of basal ramets in A. philoxeroides but not in A. sessilis under low and high contrast. At the whole fragment level, the benefits of clonal integration increased with increasing patch contrast, and such a positive effect was more pronounced in A. philoxeroides than in A. sessilis. This study demonstrated that A. philoxeroides possesses a stronger ability of clonal integration than A. sessilis, especially in patchy environments with a higher degree of heterogeneity, suggesting that clonal integration may give some invasive clonal plants a competitive advantage over native species, thus facilitating their invasion in patchy habitats. [ABSTRACT FROM AUTHOR]

Hydrophyte debris decomposition may contribute to phosphorus (P) release from the sediments in riverine systems, but the transport and transformation of organic phosphorus during this process has not been studied well. Here, a ubiquitous hydrophyte in southern China (Alternanthera philoxeroides, A. philoxeroides) was selected to identify the processes and mechanisms of sedimentary P release in late autumn or early spring by laboratory incubation. The results showed that the physio-chemical interactions changed quickly during the beginning of the incubation, where the redox potential and dissolved oxygen at the water-sediment interface decreased rapidly, reaching reducing (299 mV) and anoxic (0.23 mg∙L-1) conditions, respectively. Soluble reactive P, dissolved total P and total P concentrations in overlying water all increased with time from 0.011, 0.025 and 0.169 mg∙L-1 to 0.100, 0.100 and 0.342 mg∙L-1 on average, respectively. Furthermore, the decomposition of A. philoxeroides induced sedimentary organic P release to overlying water, including phosphate monoester (Mono-P), and orthophosphate diesters (Diesters-P). The proportions of Mono-P and Diesters-P were higher at 3 to 9 days than at 11 to 34 days, being 29.4% and 23.3 for Mono-P, 6.3% and 5.7% for Diesters-P, respectively. Orthophosphate (Ortho-P) increased from 63.6 to 69.7% during these timeframes, which indicated the transformations of both Mono-P and Diester-P to bio-available orthophosphate (Ortho-P), causing the rising P concentration in the overlying water. Our results revealed that hydrophyte debris decomposition in river systems might lead to autochthonous P contribution even without external P import from the watershed, accelerating the trophic state of receiving waterbodies. [ABSTRACT FROM AUTHOR]

Plant invasions are closely related to environmental filtering and biointeractions; however, the variations in invasive plant niches along latitudinal gradients in heterogeneous habitats remain unclear. In this study, we conducted a two-year survey in China spanning 21° N–37° N to explore the niche characteristics of plant species within communities invaded by the amphibious alien weed Alternanthera philoxeroides in both terrestrial and aquatic habitats as well as their latitudinal trends. We found that A. philoxeroides had the greatest niche breadth in the studied communities. The species pairs with the highest niche similarity were A. philoxeroides–Digitaria sanguinalis in terrestrial communities and Cyperus rotundus–Kyllinga brevifolia in aquatic communities. The niche similarity between A. philoxeroides and its accompanying species in terrestrial habitats was significantly higher than that in aquatic habitats (t = 5.954; p < 0.001). The niche breadth of A. philoxeroides had no obvious latitudinal trend, while the niche breadth of its accompanying species in the terrestrial community significantly decreased with increasing latitude (F7, 57 = 4.364, p = 0.001). In the terrestrial communities, the niche similarity between A. philoxeroides and its accompanying species significantly decreased with increasing latitude (F7, 57 = 3.671, p = 0.003), while the niche overlap significantly increased with increasing latitude (F7, 57 = 8.916, p < 0.001). However, the aquatic species' niche characteristics had no obvious latitudinal trends. These findings indicated that habitat heterogeneity significantly affected the species' niche characteristics in A. philoxeroides-invaded communities. Environmental filtering at low latitudes allowed the invasive and accompanying species to evolve similar niches, while the cold climate at high latitudes increased the niche overlap between the invader and accompanying species. Our findings are crucial for predicting the dynamics of invasive plant communities under global change and for understanding the mechanisms of species coexistence. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of information processing in plants remains a challenging task even in the era of machine learning and artificial neural networks. Sir J.C. Bose had demonstrated through his experiments that the various modes of stimulation which effectively initiated nervous impulse in animals led to impulse generation in the excitable plant Mimosa pudica as well. In order to localize the tissue responsible for conduction of excitation in the petiole of Mimosa, Bose had constructed a specialized 'Electric Probe' (glass tip electrode). From this experiment, Bose found that there were different intensities of transmitted excitation in different tissue layers of the petiole. In this backdrop, an experimental research has been conducted to comparatively study the pattern of spatial voltage distribution across different tissue layers in both, a nonexcitable plant Alternanthera philoxeroides (in stem) and an excitable plant Mimosa pudica (in petiole), by following experimental principles similar to that of Sir J. C. Bose. For the present experimental study, the electrical probes (glass tip electrode), similar to the one designed by J.C. Bose and the whole experimental setup has been constructed and developed completely in the laboratory. The results indicated a striking difference in the spatial voltage distribution pattern between the non-excitable and the excitable plant. Since Mimosa is an excitable plant having specialized mechanoreceptor cells, the change in spatial voltage distribution in the different layers of petiole, following excitation (uniform electrical stimuli) of a sub-petiole has been also studied, as an additional segment of the present research. In the present study a notable difference in the intensities of the transmitted excitation was also found upon electrical stimulation of one of the sub-petioles of the excitable plant M. pudica. [ABSTRACT FROM AUTHOR]

-In order to clarify the synergistic effect of 3% lecithin + vitamin E (AnnGro® ) on glyphosate and its absorption and conduction characteristics in plants. Alternanthera philoxeroides was taken asexperimental material. The ED50 and ED90 values of AnnGro® mixed with two glyphosate-isopropylammonium (FD and RD) were calculated by bioassay, and the surface tension, and the contact angle of the liquid with the leaf surface were tested. The absorption and conduction of 14C-glyphosate in A. philoxeroides were measured by isotope tracer technique. The results showed that A. philoxeroides died one day earlier when treated by two herbicides mixed with AnnGro® than by the herbicides alone. ED50 and ED90 values were significantly decreased by 34.9%, 21.4%, and 35.9%, 23.3% respectively. The surface tension and the contact angle between the liquid and the leaf were significantly decreased. Four days after treatments, the total absorption amount of 14C-glyphosate, the total conduction amount in plant and the downward conduction amount of 14C-glyphosate in the treatment of 14C-glyphosate + AnnGro® were 2.33, 2.34 and 2.36 times compared with the treatment of 14C-glyphosate only. In conclusion, AnnGro® improved the control efficacy of glyphosate on A. philoxeroides by increasing the absorption and the conduction in A. philoxeroides. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the impact of microplastics and heavy metals (Pb, Cd, Cr, Cu, Zn, Ni) on sediments, water, aquatic plants (Pistia stratiotes, Alternanthera philoxeroides, and Ipomoea carnea), and fish (Labeo rohita) samples collected from five different sites in the Bajwat wetlands in Sialkot, Pakistan. The concentrations of Pb, Cd, and Cr were above the permissible limits devised by WHO in all the ecosystem components (i.e. sediments, water, plants, and fish) at all sites. The maximum amount of microplastic particles (2317 microplastic particles per kg of sediments) was recorded at Site 1. The filaments were the most commonly found type of microplastics. Plants and fish samples also showed considerable concentration of metals. The multivariate statistical analysis revealed anthropogenic sources of elevated concentrations of metal elements which could cause adverse biological effects in the ecosystem. [ABSTRACT FROM AUTHOR]

Soil nitrogen can significantly affect the morphology, biomass, nutrient allocation, and photosynthesis of alien vs. native plants, thereby changing their coexistence patterns; however, the effect of soil nitrogen on the interspecific relationship between alien plants is currently unclear. We conducted a nitrogen addition experiment in a greenhouse to explore the effect of soil nitrogen on the interspecific relationship between invasive alien weed Alternanthera philoxeroides and the noninvasive alien horticultural plant Oxalis articulata. We set three experimental factors—nitrogen treatment, planting type, and species and measured the morphology, biomass, carbon (C) and nitrogen (N) content, physiological traits, and photosynthetic fluorescence of the studied plant species. We then used multi-way ANOVA and multiple comparisons to examine the differences in the above indicators among treatment combinations. We found that, in mixed cultures, nitrogen addition significantly increased the root area of O. articulata by 128.489% but decreased the root length by 56.974% compared with the control, while it significantly increased the root length of A. philoxeroides by 130.026%. Nitrogen addition did not affect the biomass accumulation of these two plant species; however, the biomass and root/shoot ratio of O. articulata were significant higher than those of A. philoxeroides. Nitrogen addition significantly increased the N content of A. philoxeroides by 278.767% and decreased the C:N ratio by 66.110% in mixed cultures. Nitrogen addition caused a significant trade-off between flavonoid and anthocyanin in O. articulata, and decreased the initial fluorescence (F0) and maximal fluorescence (Fm) of A. philoxeroides by 18.649 and 23.507%, respectively, in mixed cultures. These results indicate that nitrogen addition increased the N absorption and assimilation ability of A. philoxeroides in deep soil; furthermore, it significantly enhanced the advantages for O. articulata in terms of morphology, physiological plasticity, and photosynthetic efficiency. In addition, O. articulata had better individual and underground competitive advantages. Under intensified nitrogen deposition, the biotic replacement effect of O. articulata on A. philoxeroides in natural ecosystems could be further enhanced.

Aging is a well-known factor that accelerates brain deterioration, resulting in impaired learning and memory functions. This current study evaluated the potential of an extract of Alternanthera philoxeroides (AP), an edible flavonoid-rich plant, to ameliorate D-galactose-induced brain aging in male mice. Chronic administration of D-galactose (150 mg/kg/day) in mice mimicked the characteristics of aging by accelerating senescence via downregulation of the following telomere-regulating factors: mouse telomerase reverse transcriptase (mTERT) and mouse telomeric repeat-binding factors 1 (mTRF1) and 2 (mTRF2). D-galactose also decreased the activities of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), while increasing expression of neuroinflammatory cytokines in the frontal cortex and hippocampus. Daily treatment of D-galactose-induced aging mice with AP at 250 and 500 mg/kg/day or vitamin E (100 mg/kg/day) significantly increased the activities of SOD and CAT, as well as expression of mTERT, mTRF1, and mTRF2, which are involved in telomere stabilization, but decreased the levels of proinflammatory cytokines IL-1β, IL-6, and TNF-α. In the behavioral portion of the study, AP improved aging-related cognitive deficits in short-term memory as shown by the Y-maze task and the novel object recognition test (NORT) and long-term memory as shown by the Morris water maze test (MWMT). The flavones kaempferol-O-glucoside (1), quercetin (2), alternanthin B (3), demethyltorosaflavone D (4), and chrysoeriol-7-O-rhamnoside (5), which could be responsible for the observed effects of AP in the D-galactose-induced aging mice, were identified by HPLC analysis.

There is conflicting evidence from studies on the fitness consequences of plant kin interactions, suggesting that kinship is not the only important factor in determining the outcome of kin interaction.Here, we tested whether density‐dependent kin interactions have evolved from competition to cooperation by kin selection of reduced shade avoidance responses following the introduction of an invasive plant. We measured how plants respond to kin neighbours (the same accession) and simulated vegetation shade (lower PPFD and R:FR ratio treatments using transparent green plastic filters) and determine whether shade avoidance responses affect the outcome of kin interactions using five native (Argentina) and five invasive (USA) accessions of Alternanthera philoxeroides.Our results showed that invasive accessions exhibited constant stem elongation but increased total biomass as canopy density increased, while native accessions exhibited the opposite. Furthermore, invasive accessions reduced stem elongation, but increased biomass and defence allocation in response to an experimental treatment causing a low R:FR ratio, while native accessions exhibited the opposite.Synthesis. Our results support the hypothesis that kin selection against shade avoidance may effectively promote the evolution of density‐dependent kin cooperation. This suggests that kin selection pressures may play a more important role in fine‐tuning plant shade avoidance responses than generally thought. Kin selection against selfish shade avoidance behaviour and release from negative density‐dependent regulation provides a new mechanism to explain plant invasion success for future studies. [ABSTRACT FROM AUTHOR]

Plants' ability to sense and respond to gravity is a unique and fundamental process. When a plant organ is tilted, it adjusts its growth orientation relative to gravity direction, which is achieved by a curvature of the organ. In higher, multicellular plants, it is thought that the relative directional change of gravity is detected by starch-filled organelles that occur inside specialized cells called statocytes, and this is followed by signal conversion from physical information to physiological information within the statocytes. The classic starch statolith hypothesis, i.e., the starch accumulating amyloplasts movement along the gravity vector within gravity-sensing cells (statocytes) is the probable trigger of subsequent intracellular signaling, is widely accepted. Acharya Jagadish Chandra Bose through his pioneering research had investigated whether the fundamental reaction of geocurvature is contractile or expansive and whether the geo-sensing cells are diffusedly distributed in the organ or are present in the form of a definite layer. In this backdrop, a microscopy based experimental study was undertaken to understand the distribution pattern of the gravisensing layer, along the length (node–node) of the model plant Alternanthera philoxeroides and to study the microrheological property of the mobile starch-filled statocytes following inclination-induced graviception in the stem of the model plant. The study indicated a prominent difference in the pattern of distribution of the gravisensing layer along the length of the model plant. The study also indicated that upon changing the orientation of the plant from vertical position to horizontal position there was a characteristic change in orientation of the mobile starch granules within the statocytes. In the present study for the analysis of the microscopic images of the stem tissue cross sections, a specialized and modified microscopic illumination setup was developed in the laboratory in order to enhance the resolution and contrast of the starch granules. [ABSTRACT FROM AUTHOR]

The effects of invasive species on the local community (e.g., structure and stability) are highly environmentally dependent. Invasions of amphibious species usually take place in both xeric and humid environments, yet they are relatively poorly understood. In this study, we analyzed the communities that were dominated by Alternanthera philoxeroides using ecological niche and interspecific association. A total of 66 species and 67 species were recorded in the xeric environment and humid environment, respectively. In both environments, species in family Gramineae, such as Echinochloa crusgalli and Cynodon dactylon, exhibited a higher level of importance values and greater ecological niche widths. The interspecific association and stability of the dominant species were weak and the dominant species were relatively independent of each other. In the xeric environment, A. philoxeroides was more compatible with E. crusgalli and C. dactylon in terms of ecological niche requirements and habitat suitability. In humid habitats, A. philoxeroides had a greater correlation with E. crusgalli, C. dactylon, and Persicaria lapathifolia, suggesting a higher possibility of concomitant occurrence. Overall, we suggested that during the revegetation after A. philoxeroides invasion, E. crusgalli and C. dactylon can be the alternative plants. Meanwhile, alternative control measures for A. philoxeroides invasion in agricultural fields should give more consideration to the use of plants with economic or ecological value. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: The chrysomelid beetle Agasicles hygrophila is an effective natural enemy used in the biocontrol of the invasive weed Alternanthera philoxeroides. However, few studies have focused on the cold acclimation of A. hygrophila. We investigated the effects of exposure to different sub-lethal low temperatures for different durations on biological indices of adult male and female A. hygrophila and subsequently selected an appropriate acclimation temperature to enhance low-temperature tolerance. We found that A. hygrophila can acclimate to the cold and that this acclimation can enhance the cold tolerance of this beetle at −10 °C. Moreover, an appropriate acclimation temperature and time were found to enhance the survival and longevity of captive-bred A. hygrophila adults, which has ecological relevance for the biological control of A. philoxeroides in cold areas of northern China. Agasicles hygrophila Selman and Vogt is used in the biological control of the invasive weed Alternanthera philoxeroides (Mart.) Griseb. However, with the northward establishment of A. philoxeroides in China, the weak adaptivity of A. hygrophila to cold weather has resulted in the ineffective control of A. philoxeroides in northern China. Cold acclimation can significantly enhance insect cold tolerance, enabling them to cope with more frequent climate fluctuations. To improve the biological control efficacy of A. hygrophila in cold climates, we compared the effects of rapid cold hardening and acclimation on A. hygrophila under laboratory conditions. On initially transferring adults from 26 to −10 °C for 2 h, mortality reached 80%. However, when pre-exposed to 0 °C for 2 h and then transferred to −10 °C for 2 h, adult mortality was reduced to 36.67%. These findings indicate that cold acclimation can enhance the cold tolerance of A. hygrophila under laboratory conditions. However, the beneficial cold acclimation effects waned after more than 15 min of recovery at 26 °C. Exposure to 15 °C for 24 h or gradual cooling from 0 to −10 °C at 1 °C·min−1 also induced cold acclimation, indicating that long-term cold and fluctuating cold acclimation are also potentially effective strategies for enhancing low-temperature tolerance. [ABSTRACT FROM AUTHOR]

Resource utilization of dried livestock sewage sludge (SS) and invasive plants, e.g. Alternanthera philoxeroides (AP) is the focus of cracking the environmental challenges. In this study, AP and sludge were used as raw materials to prepare co-pyrolysis biochar at 300–800 °C. The total amount of heavy metals, BCR forms, and leaching toxicity were analyzed to evaluate the environmental risk of heavy metals (HMs) in biochar. The results showed that the percentage of unstable states and leaching toxicity of six (HMs) decreased, and the total amount and ratio of stable states increased with the increasing pyrolysis temperature. Compared with SS and SBCs, the unstable fraction and leaching toxicity of (HMs) in SABCs were significantly reduced, and the values of RAC and RI were lower. The RI value of SS was 1001.40, which belongs to a very high-risk level, while the RI of SABC800 was low risk with a value of 51.69, indicating that the co-pyrolysis of AP and SS at high temperatures could effectively reduce the environmental risk of biochar. In addition, the E r value of Cd in SBCs was significantly higher than that of SS, but it was lower in SABCs than in SS, which suggested that AP addition is beneficial to reducing the ecotoxicity and environmental risk of Cd in livestock sewage sludge. This study demonstrates the superiority of AP addition in reducing the environmental risk of (HMs), especially Cd in SS, and provides a new idea of resource utilization for invasive plants and livestock sewage sludge disposal. • RI of HMs in sludge was 1001.40 belonging to high risk and ecotoxicity. • AP addition significantly reduced the environmental risk of Cd. • SABC800 had the lowest environmental risk of HMs with the RI value of 51.69. • Increasing pyrolysis temperature and adding AP jointly promote the transformation of HMs to stable states. [ABSTRACT FROM AUTHOR]

Endophytic microbes have been associated with many positive traits due to their endurance mechanisms. The current study was designed at exploring the potential of the endophytic bacterium Bacillus amyloliquefaciens MEBAphL4 isolated from Alternanthera philoxeroides for biosurfactant production and bioremediation efficiency. This endophyte, isolated from the polluted Madiwala lake in Bangalore, displayed elevated resistance to Cr and Pb till 2000 mg/L. The metal removal efficiency was found to be higher for Cr (25.7 %) at pH 6 and for Pb (92.3 %) at pH 9. Further, the present study also describes biosurfactant production with good emulsification ability (E 24 -52 %) and stability over a range of pH (8−12), temperature (20–40°C) and salinity (5–15 %). Biosurfactant production was enhanced 1.18-fold using the Response Surface Methodology approach and characterised by Fourier Transformation Infra-red Spectroscopy and Ultra-Performance Liquid Chromatography- Mass Spectrometry showing the presence of lipopeptides, fengycin, iturin and surfactin of molecular weights 1463.65, 1043.44 and 1012.56 Da respectively. The potential application of the biosurfactant in degrading various hydrocarbons was evaluated, demonstrating its effectiveness in bioremediation of oil-contaminated sites. Specifically, diesel biodegradation was measured at 56.46±0.95 %. These findings underscore the potential of B. amyloliquefaciens in environmental applications such as heavy metal biosorption and the bioremediation of contaminated sites, particularly those affected by oil spills and correlates to UN SDG6 of clean water and sanitation. • Endophytic Bacillus amyloliquefaciens showed heavy metal tolerance for Chromium (Cr) and Lead (Pb) up to 2000 mg/L. • The bacterium could reduce 100 mg/L of Cr (VI) by 50.8 % in 24 hours. • It exhibited heavy metal removal efficiencies of 25.7 % for Cr at pH 6 and 92.3 % for Pb at pH 9. • The RSM optimization maximized the biosurfactant production by 1.18-fold. • The lipopeptides fengycin, iturin, and surfactin have potential for bioremediation of oil-contaminated sites. [ABSTRACT FROM AUTHOR]

Plant invasions pose a serious environmental problem around the world. The release of heavy metals and nutrients into natural habitats due to human activities is increasing. However, whether nutrient increase can influence the response of invasive plants to heavy metals has been little studied. We hypothesized that increased nutrient availability promotes the growth of invasive plants under heavy metal stress. To test this hypothesis, we conducted a greenhouse experiment on the invasive, widespread, clonal plant Alternanthera philoxeroides. The experiment used a factorial design: a single clonal fragment of A. philoxeroides at three levels of cadmium (Cd) fully crossed with four levels of nutrient availability for four weeks. Increased nutrient availability significantly increased the growth of plants under Cd stress. Moreover, the responses of node number, main stem length, and root-shoot ratio to Cd stress varied among different levels of nutrient availability, which indicates that nutrients can affect the clonal reproduction, stem morphology and biomass allocation of A. philoxeroides under Cd stress. Our results support the hypothesis that increased nutrient availability alleviates the adverse effects of heavy metals on invasive plants. Invasive species such as A. philoxeroides may successfully grow in heavy metal-polluted areas more easily under high nutrient availability. [ABSTRACT FROM AUTHOR]

To assess how the presence of an invasive plant and different-sized decomposers affect plant litter decomposition under different seasonal conditions, we allocated leaves of native Ficus virens Aiton into four different mesh sizes (0.025, 0.042, 0.5 and 5 mm) with and without invasive Alternanthera philoxeroides (Mart.) Griseb. We incubated them for 65 days in an eutrophic lake in summer and winter respectively. The average decomposition rate was significantly higher in summer than in winter, and was significantly higher in mixtures than in F. virens monocultures in both seasons. The presence of A. philoxeroides in the mixture significantly increased invertebrate density and microbial respiration rates in summer but not in winter. Furthermore, contribution of invertebrates to decomposition was higher in the early stage of decomposition and lower in the late stage in summer, yet that of microbes was relatively constant in winter. Contribution of microinvertebrates increased in summer but that of meio-, macroinvertebrates increased in winter. Our findings indicate that the presence of an invasive plant altered litter decomposition, which may depend on seasonal variations, invertebrate density and decomposition stages. [ABSTRACT FROM AUTHOR]

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 (b) 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 b diversity in aquatic habitatswere all significantly higher than that of terrestrial, while the terrestrial habitat had a higher community similarity values. The aquatic A. philoxeroides IV increasedwith 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 fromhygrophytes 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. [ABSTRACT FROM AUTHOR]

Parental environmental effects can be a rapid and effective means for clonal plants in response to temporally or spatially varying environments. However, few studies have quantitatively measured the ecological significance of parental effects in aquatic clonal plants. In this study, we developed a two-generation (parent-offspring) growth model to examine the parental effects of nitrogen (N) conditions on summed and mean performance of clonal offspring of one wetland species Alternanthera philoxeroides. We also examined the role of survival status and developmental stage of clonal offspring in the consequence of parental effects in aquatic clonal plants. Our results indicated direct evidence that (1) there were significant nonlinear correlations between the performance of parental plants and initial status of clonal offspring (i.e., the mass and number of clonal propagules); (2) parental N effects on the summed performance of clonal offspring were content-dependent (i.e., there were significant interactions between parental and offspring N effects), while parental effects on the mean performance of offspring were independent of offspring conditions; (3) parental effects mainly occurred at the early development stage of clonal offspring, and then gradually declined at the late stage; (4) the context-dependent parental effects on the summed performance of clonal offspring gradually strengthened when offspring survival was high. The mathematical models derived from the experimental data may help researchers to not only deeply explore the ecological significance of parental environmental effects in aquatic clonal plants, but also to reveal the importance of potential factors that have been often neglected in empirical studies. [ABSTRACT FROM AUTHOR]

Purpose: Benefits of clonal integration have been widely documented in clonal species, but quantitative tests of the translocation of resources in both directions between older and younger ramets (e.g., transport rate and partitioning pattern) are still scarce. Methods: A control experiment, using a clonal species Alternanthera philoxeroides as plant material and the technique of 15N isotope, was conducted to quantify the transport rate of nitrogen (N) in two opposite directions (i.e., from younger to older ramets or the other way around) within a clone, and the partitioning proportion of N in recipient ramets. Results: The amount of 15N transported toward the apical part was markedly reduced at the higher external N level, whereas the amount of 15N transported toward the basal part was unrelated to the external N levels. The rate of 15N acropetal transport basically averaged 20.9%, and the rate of 15N basipetal transport generally ranged between 0.2% and 6.3%, both being negatively dependent of ΔPNC (i.e., difference in plant N concentration [PNC] between apical and basal parts). The proportion of 15N in stems and leaves averaged 74.7% and 18.1%, respectively; the proportion of root 15N in the apical part significantly decreased from 7.6% to 0.4% when acropetal transport occurred. Conclusion: These results suggest that N sharing between connected ramets tended to be acropetal and the partitioning pattern of N is organ-specific in A. philoxeroides, which potentially contributes to the early development of young ramets, and also to the spread of A. philoxeroides in limited N conditions. [ABSTRACT FROM AUTHOR]

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Plants release a variety of volatiles and herbivore-induced plant volatiles (HIPVs) after being damaged by herbivorous insects, which play multiple roles in the interactions with other plants and insects. Agasicles hygrophila Selman and Vogt (Coleoptera: Chrysomelidae) is a monophagous natural enemy and an effective biocontrol agent for Alternanthera philoxeroides (Mart.) Griseb. Here, we reported differences among the volatiles of A. philoxeroides by solid phase microextraction (SPME) using a gas chromatography-mass spectrometer (GC-MS). We compared the volatile emission of: (1) clean plants (CK); (2) A. philoxeroides plants with mechanical damage treatment (MD); and (3) A. philoxeroides plants infested with A. hygrophila 1st, 2nd, and 3rd larvae and female and male adults. A total of 97 volatiles were recorded, of which 5 occurred consistently in all treatments, while 61 volatiles were only observed in A. philoxeroides infested by A. hygrophila, such as trans-nerolidol, (E)-β-farnesene, and (3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (E, E-TMTT), etc. Among the 97 volatile compounds, 37 compounds belong to alkenes, 29 compounds belong to alkanes, and there were 8 esters, 8 alcohols and 6 ketones. Orthogonal partial least squares-discrimination analysis (OPLS-DA) showed that the different treatments were separated from each other, especially insect feeding from CK and MD treatments, and 19 volatiles contributed most to the separation among the treatments, with variable importance for the projection (VIP) values > 1. Our findings indicated that the alligatorweed plants could be induced to release volatiles by different stages of A. hygrophila, and the volatile compounds released differ quantitatively and qualitatively. The results from this study laid an important foundation for using volatile organic compounds (VOCs) and HIPVs of alligatorweed to improve the control effect of A. hygrophila on A. philoxeroides. [ABSTRACT FROM AUTHOR]

Different connected parts of clonal plants often grow in different patches and the resource contrast between patches has an important effect on the material transfer between the connected ramets. However, it is unclear whether the effect of clonal integration differs between the invasive clonal plant and the related native species in response to patch contrast. To explore this, we grew the clonal fragment pairs of plant invader Alternanthera philoxeroides and its co-genus native species A. sessilis under high contrast, low contrast, and no contrast (control) nutrient patch environments, respectively, and with stolon connections either severed or kept intact. The results showed that, at the ramet level, clonal integration (stolon connection) significantly improved the growth of apical ramets of both species, and such positive effects were significantly greater in A. philoxeroides than in A. sessilis. Moreover, clonal integration greatly increased the chlorophyll content index of apical ramets and the growth of basal ramets in A. philoxeroides but not in A. sessilis under low and high contrast. At the whole fragment level, the benefits of clonal integration increased with increasing patch contrast, and such a positive effect was more pronounced in A. philoxeroides than in A. sessilis. This study demonstrated that A. philoxeroides possesses a stronger ability of clonal integration than A. sessilis, especially in patchy environments with a higher degree of heterogeneity, suggesting that clonal integration may give some invasive clonal plants a competitive advantage over native species, thus facilitating their invasion in patchy habitats.

Plant invasions are closely related to environmental filtering and biointeractions; however, the variations in invasive plant niches along latitudinal gradients in heterogeneous habitats remain unclear. In this study, we conducted a two-year survey in China spanning 21° N–37° N to explore the niche characteristics of plant species within communities invaded by the amphibious alien weed Alternanthera philoxeroides in both terrestrial and aquatic habitats as well as their latitudinal trends. We found that A. philoxeroides had the greatest niche breadth in the studied communities. The species pairs with the highest niche similarity were A. philoxeroides–Digitaria sanguinalis in terrestrial communities and Cyperus rotundus–Kyllinga brevifolia in aquatic communities. The niche similarity between A. philoxeroides and its accompanying species in terrestrial habitats was significantly higher than that in aquatic habitats (t = 5.954; p < 0.001). The niche breadth of A. philoxeroides had no obvious latitudinal trend, while the niche breadth of its accompanying species in the terrestrial community significantly decreased with increasing latitude (F7, 57 = 4.364, p = 0.001). In the terrestrial communities, the niche similarity between A. philoxeroides and its accompanying species significantly decreased with increasing latitude (F7, 57 = 3.671, p = 0.003), while the niche overlap significantly increased with increasing latitude (F7, 57 = 8.916, p < 0.001). However, the aquatic species’ niche characteristics had no obvious latitudinal trends. These findings indicated that habitat heterogeneity significantly affected the species’ niche characteristics in A. philoxeroides-invaded communities. Environmental filtering at low latitudes allowed the invasive and accompanying species to evolve similar niches, while the cold climate at high latitudes increased the niche overlap between the invader and accompanying species. Our findings are crucial for predicting the dynamics of invasive plant communities under global change and for understanding the mechanisms of species coexistence.

Plants growing in nutrient-rich environment are predicted to be less defended than conspecifics under nutrient limitation. However, less is known about the effects of nutrient levels on tolerance and induced resistance, and whether the effects differ between native and introduced populations of invasive plants. We performed a greenhouse experiment with introduced (the USA) and native (Argentina) genotypes of Alternanthera philoxeroides in order to study the effects of soil nitrogen levels on plant growth, constitutive and herbivore (Agasicles hygrophila)-induced chemical defense, and herbivory tolerance. We measured total biomass, elongation rate (as proxy of growth rate), carbon and nitrogen, and the concentration of triterpenoid saponins (defensive chemicals) in leaves and roots. Constitutive resistance (+33% higher leaf triterpenoid saponins in control treatment at low nitrogen level) and tolerance [less decreased total biomass after herbivory treatment (−24% and −15% for high and low nitrogen levels)] were favored at lower nitrogen level, while induced resistance was favored at higher nitrogen level (+24% increased leaf triterpenoid saponins after herbivory treatment at high nitrogen level). Constitutive resistance and tolerance exhibited trade-offs with growth rate, while induced resistance positively correlated with growth rate. Additionally, the introduced genotypes had −6% lower content of leaf carbon in the presence of herbivores than the native genotypes at low nitrogen level, but such difference was absent at high nitrogen level. Our results indicate that soil nitrogen levels influence the preference of different defensive strategies of plant, and interweave with herbivory to determine the performance of introduced genotypes. [ABSTRACT FROM AUTHOR]