The potential anti-Alzheimer's activity of Oxalis corniculata Linn. Methanolic extract in experimental rats: Role of APOE4/LRP1, TLR4/NF-κß/NLRP3, Wnt 3/ß-catenin/GSK-3ß, autophagy and apoptotic cues.

ETHNOPHARMACOLOGICAL RELEVANCE: Oxalis corniculata (O. corniculata) is a member of Oxalidaceae family, widely distributed in Asia, Europe, America, and Africa, used extensively as food and its traditional folkloric uses include management of epilepsy, gastric disorders, and neurodegenerative diseases, together with its use in enhancing health. Numerous pharmacological benefits of O. corniculata are linked to its anti-inflammatory and antioxidant abilities. One of the most prevalent neurodegenerative disorders is Alzheimer's disease (AD) in which neuroinflammation and oxidative stress are its main pathogenic processes. AIM OF THE STUDY: Our research aimed to study the neuroprotective effect of the methanolic extract of Oxalis corniculata Linn. (O. corniculata ME), compared to selenium (Se) against AlCl3-induced AD. MATERIALS AND METHODS: Forty male albino rats were allocated into four groups (Gps). Gp I a control group, the rest of the animals received AlCl3 (Gp II-Gp IV). Rats in Gp III and IV were treated with Se and O. corniculata ME, respectively. RESULTS: The chemical profile of O. corniculata ME was studied using ultraperformance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry, allowing the tentative identification of sixty-six compounds, including organic acids, phenolics and others, cinnamic acid and its derivatives, fatty acids, and flavonoids. AlCl3 showed deterioration in short-term memory and brain histological pictures. Our findings showed that O. corniculata ME and selenium helped to combat oxidative stress produced by accumulation of AlCl3 in the brain and in prophylaxis against AD. Thus, Selenium (Se) and O. corniculata ME restored antioxidant defense, via enhancing Nrf2/HO-1 hub, hampered neuroinflammation, via TLR4/NF-κß/NLRP3, along with dampening apoptosis, Aß generation, tau hyperphosphorylation, BACE1, ApoE4 and LRP1 levels. Treatments also promoted autophagy and modulated Wnt 3/ß-catenin/GSK3ß cue. CONCLUSIONS: It was noted that O. corniculata ME showed a notable ameliorative effect compared to Se on Nrf2/HO-1, TLR4/NF-κß/NLRP3, APOE4/LRP1, Wnt 3/ß-catenin/GSK-3ß and PERK axes.

Oxali-palladium nanoparticle synthesis, characterization, protein binding, and apoptosis induction in colorectal cancer cells.

This paper focuses on the synthesis of nano-oxali-palladium coated with turmeric extract (PdNPs) using a green chemistry technique based on the reduction in the Pd (II) complex by phytochemicals inherent in turmeric extract. PdNPs were examined and characterized using Field Emission Scanning Electron Microscopy (FESEM), Dynamic Light Scattering (DLS), Fourier Transform Infrared (FTIR), and Atomic Force Microscopy (AFM). Using different spectroscopic and molecular dynamics simulations, a protein-binding analysis of the produced nanoparticle was conducted by observing its interaction with human serum albumin (HSA). Lastly, the cytotoxic effects and apoptotic processes of PdNPs were studied against the HCT116 human colorectal cell line using the MTT assay and flow cytometry tests. According to the findings, PdNPs with spherical and homogenous morphology and a size smaller than 100 nm were generated. In addition, they can induce apoptosis in colorectal cancer cells in a dose-dependent manner with a lower Cc50 (78 µL) than cisplatin and free oxali-palladium against HCT116 cells. The thermodynamic characteristics of protein binding of nanoparticles with HSA demonstrated that PdNPs had a great capacity for quenching and interacting with HSA through hydrophobic forces. In addition, molecular dynamics simulations revealed that free oxali-palladium and PdNP attach to the same area of HSA via non-covalent interactions. It is conceivable to indicate that the synthesized PdNPs are a potential candidate for the construction of novel, nature-based anticancer treatments with fewer side effects and a high level of eco-friendliness.

Oxali(IV)Fluors: Fluorescence Responsive Oxaliplatin(IV) Complexes Identify a Hypoxia-Dependent Reduction in Cancer Cells.

Platinum(IV) anticancer agents have demonstrated the potential to overcome the limitations associated with the widely used Pt(II) chemotherapeutics, cisplatin, carboplatin, and oxaliplatin. In order to identify therapeutic scenarios where this type of chemotherapy can be applied, an improved understanding on the intracellular reduction of Pt(IV) complexes is needed. Here, we report the synthesis of two fluorescence responsive oxaliplatin(IV)(OxPt) complexes, OxaliRes and OxaliNap. Sodium ascorbate (NaAsc) was shown to reduce each OxPt(IV) complex resulting in increases in their respective fluorescence emission intensities at 585 and 545 nm. The incubation of each OxPt(IV) complex with a colorectal cancer cell line resulted in minimal changes to the respective fluorescence emission intensities. In contrast, the treatment of these cells with NaAsc showed a dose-dependent increase in fluorescence emission intensity. With this knowledge in hand, we tested the reducing potential of tumor hypoxia, where an oxygen-dependent bioreduction was observed for each OxPt(IV) complex with <0.1% O2 providing the greatest fluorescence signal. Clonogenic cell survival assays correlated with these observations demonstrating significant differences in toxicity between hypoxia (<0.1% O2) and normoxia (21% O2). To the best of our knowledge, this is the first report showing carbamate-functionalized OxPt(IV) complexes as potential hypoxia-activated prodrugs.

Colorimetric active carboxymethyl chitosan/oxidized sodium alginate-Oxalis triangularis ssp. papilionacea anthocyanins film@gelatin/zein-linalool membrane for milk freshness monitoring and preservation.

Colorimetric active double-layer composites of film@membrane were developed via direct electrospinning functional nanofibers on colorimetric film. In the structure, oxidized sodium alginate cross-linked carboxymethyl chitosan (CO) was used as colorimetric film matrix to incorporate the anthocyanins extract from Oxalis triangularis ssp. papilionacea (OTA); while the blend of gelatin/zein (GZ) was used as fibrous matrix for linalool (L) encapsulation. Besides good barrier and water resistance, the outer-layer of CO-OTA showed colorimetric sensitivity towards pH-stimuli with reversible color changes. The inner-layer of GZ-L exhibited good antibacterial activities against Staphylococcus aureus and Escherichia coli. The volatile release of L from fibrous matrix was well controlled and mainly followed Fickian diffusion. Moreover, the antioxidant activity of the composites is source from the released linalool. The high reliability on milk freshness monitoring and double shelf-life extending at 25 °C suggest the potential of CO-OTA@GZ-L in colorimetric active food packaging.

[Biological mechanisms of Oxalis corniculata regulating human prostate cancer PC-3 cells: An investigation based on the NF-κB pathway].

OBJECTIVE: To investigate the biological mechanisms underlying the effect of the Chinese herbal medicine Oxalis corniculata on human prostate cancer PC-3 cells. METHODS: Through in vitro experiment, we treated human prostate cancer PC-3 cells with different concentrations of Oxalis corniculata, assessed the viability of the cells by MTT assay, examined their apoptosis by flow cytometry, evaluated their migration and invasiveness by Transwell assay, and determined the expressions of the proteins p65, p-p65, IκBα and p-IκBα in the NF-κB pathway using protein imprinting technology. RESULTS: Compared with the blank control, Oxalis corniculata significantly inhibited the proliferation and induced the apoptosis of the PC-3 cells (P< 0.05), suppressed their migration and invasiveness in a dose-dependent manner (P< 0.05), and upregulated the expression of IκBα and downregulated those of p-p65 and p-IκBα in the NF-κB pathway (P< 0.05). CONCLUSION: Oxalis corniculata can inhibit the proliferation, migration and invasiveness and induce the apoptosis of human prostate cancer PC cells, which may be attributed to its abilities of inhibiting the expressions of p-p65 and p-IκBα and regulating the activity of the NF-κB pathway.

[Research on the mechanism of Miao ethnicity medicine formula of Oxalis corniculata against chronic non-bacterial prostatitis].

Objective： To explore the mechanism of Miao ethnicity medicine formula of Oxalis corniculata against chronic non-bacterial prostatitis. Methods: The rat model of chronic abacterial prostatitis was induced by stimulation with 2% sterile carrageenan solution. After modeling, the rats were randomly divided into two groups, Model control group (Model group) and oxalis group. Another normal control group was set up. The rats in the Model group and the normal control group were given 0.01ml/g normal saline by gavage, and the rats in the oxalis alis group were given 1ml/100g (1 g/kg) of Oxalis corniculata L warm water decoction by gavage once a day for 28 days. Twenty-four hours after the last administration, 10ml blood was collected from the abdominal aorta of the rats, and prostate tissue samples were collected from the rats. hematoxylin-eosin (HE) staining was used to observe the morphological structure of the prostate in normal and prostatitis rats. ELISA was used to detect the levels of serum and prostate cytokines. The protein expressions of 4-HNE , ALDH2 and FGF2 were detected by Western blot. Results: Compared with the blank group, the model group showed obvious hyperplasia of fibrous tissue in the interstitium of the prostate tissue, disordered glandular structure, papillary hyperplasia of epithelial cells in the acini, infiltration of a small amount of lymphocytes, monocytes and other inflammatory cells in the acini, and increased pathological scores. The protein expressions of 4-HNE , ALDH2 , MCP-1 and FGF2 in prostate tissue were significantly increased. Compared with the model group, the prostate tissue of the oxalis group was slightly damaged, with a small amount of fibrous hyperplasia and inflammatory cell infiltration. The protein expressions of 4-HNE , ALDH2 , MCP-1 and FGF2 were decreased in prostate tissue. Conclusion： Oxalis corniculata L can effectively repair the pathological morphology of prostate tissue in rats with CNP, and its mechanism may be related to activating 4-HNE protein and reducing oxidative stress injury of prostate tissue in rats.

Inconsistent expression of the gigas effect in polyploid Oxalis.

PREMISE: It is well-known that whole genome duplication (WGD) has played a significant role in the evolution of plants. The best-known phenotypic effect of WGD is the gigas effect, or the enlargement of polyploid plant traits. WGD is often linked with increased weediness, which could be a result of fitness advantages conferred by the gigas effect. As a result, the gigas effect could potentially explain polyploid persistence and abundance. We test whether a gigas effect is present in the polyploid-rich geophyte Oxalis, at both organ and cellular scales. METHODS: We measured traits in conspecific diploid and polyploid accessions of 24 species across the genus. In addition, we measured the same and additional traits in 20 populations of the weedy and highly ploidy-variable species Oxalis purpurea L., including measures of clonality and selfing as a proxy for weediness. Ploidy level was determined using flow cytometry. RESULTS: We found substantial variation and no consistent ploidy-related size difference, both between and within species, and across traits. Oxalis purpurea polyploids did, however, produce significantly more underground biomass and more bulbils than diploids, consistent with a potential role of WGD in the weediness of this species. CONCLUSIONS: Our results suggest a more nuanced role for the gigas effect, at least in Oxalis. It may be temporary, short-lived, and inconsistently expressed and retained on evolutionary time scales, but in the short term can contribute to lineage success via increased vegetative reproduction.

An acidic polysaccharide from Oxalis corniculata L. and the preliminary study on its antioxidant activity.

It has been reported that the aqueous extract from Oxalis corniculate has excellent pharmacological effects, but its polysaccharide as the major ingredient in the aqueous extract has not been reported. When the temperature of 50°C, ultrasonic power of 270 W, time of 25 min, solid to liquid ratio of 30 ml·g-1 , the optimal O. corniculate polysaccharide (OCP) yield was 9.45%. The physicochemical properties indicated that OCP-3, as the major fraction of OCP, was an acidic polysaccharide with 31.5 kDa, and it mainly consisted of arabinose (47.83%), galacturonic acid (17.81%), and galactose (14.25%). In addition, OCP-3 displayed an excellent antioxidant activity in vitro, including scavenging free radical, anti-lipid peroxidation, and protecting plasmid DNA from oxidative damage. Meanwhile, OCP-3 significantly reduced the levels of malondialdehyde and protein carbonyl by significantly increasing the activity of superoxide dismutase, catalase, and glutathione peroxidase, which protected the HEK 293 cell and Caenorhabditis elegans from oxidative damage. All the results suggested that OCP-3 might be the major active ingredient of the aqueous extract from O. corniculate, and OCP-3 might be a potent antioxidant supplement in the food, cosmetics, and medical industries. PRACTICAL APPLICATIONS: Oxalis corniculate is a kind of wild vegetable and ethnomedicine, and it is widely distributed in temperate zones. Unfortunately, its utilization rate is low compared to its yield. Our research suggested that the polysaccharide of OCP-3 from O corniculate might be used as a potent antioxidant supplement in the food, cosmetics, and medical industries.

A Review on Phyto-pharmacology of Oxalis corniculata.

Oxalis corniculata (Oxalidaceae) is a small decumbent and delicate appearing medicinal herb flourishing in warm temperate and tropical domains such as Pakistan and India. Main bioactive chemical constituents of Oxalis plant include several alkaloids, flavonoids, terpenoids, cardiac glycosides, saponins, and phlobatannins, along with steroids. Due to its polyphenolic, glycosides and flavonoid profile, it is proved to be protective in numerous ailments and exhibit various biological activities such as anti-fungal, anti-cancer, anti-oxidant, antibacterial, anti-diabetic, and cardioprotective. Moreover, bioactive phytochemicals from this plant possess significant wound healing potential. Our current effort intends to emphasize on the immense significance of this plant species, which have not been the subject matter of clinical trials and effective pharmacological studies, even though its favored usage has been stated. This review proposes that Oxalis corniculata possess a potential for the cure of various diseases. However, further researches on isolation and characterization of bioactive compounds along with pre-clinical trials are compulsory to figure out its pharmacological applications.

Phytochemical characterization, antioxidant potential and antimicrobial activity of Averrhoa carambola L. (Oxalidaceae) against multiresistant pathogens / Caracterização fitoquímica, potencial antioxidante e atividade antimicrobiana de Averrhoa carambola L. (Oxalidaceae) frente a patógenos multirresistentes

Abstract The objective of this work was to perform the phytochemical characterization, to determine total phenols, antioxidant (AAO%) and antimicrobial potential of the ethanolic extracts of carambola. The phytochemical study was carried out through a qualitative analysis of the chemical constituents and quantitative determination of the phenol content By the Folin-Ciocalteu test. Qualitative and quantitative antioxidant tests were performed using the DPPH method (2,2 diphenyl-1-picryl-hydrazila) and iron reduction (FRAP). The minimum inhibitory concentration (MIC) was determined by microdilution in 96-well plates. The presence of pyrogallic tannins, steroids and saponins has been identified. The highest total phenol content, quantified in the samples, was found in the stem bark (0.0866 mgEAG/g) and in the fruit (0.0734 mgEAG/g). In the antioxidant evaluation, the extracts of the green fruit bagasse (AAO% 71.9%,) and stem bark at 50 μg/mL (AAO% 94%) with CE50 23.7 μg/mL. Leaf extracts, stem bark, ripe fruit bagasse and green fruit bagasse presented MICs of 100 μg/mL against multiresistant pathogenic bacteria and fungi.

Resumo O objetivo desse trabalho foi realizar a caracterização fitoquímica, determinar fenóis totais, potencial antioxidante (AAO%) e antimicrobiano dos extratos etanólicos de carambola O estudo fitoquímico foi realizado por meio de análise qualitativa dos constituintes químicos e determinação quantitativa do teor de fenóis totais pelo teste de Folin-Ciocalteu. Os testes antioxidantes qualitativos e quantitativos foram realizados pelo método do DPPH (2,2 difenil-1- picril-hidrazila) e redução do ferro (FRAP). A concentração inibitória mínima (CIM) foi determinada por microdiluição em placas de 96 poços. Foi identificada a presença de taninos pirogálicos, esteroides e saponinas. O maior teor de fenóis totais, quantificado nas amostras, foi encontrado na casca do caule (0,0866 mg EAG/g) e no fruto (0,0734 mg EAG/g). Na avaliação antioxidante destacaram-se a 500 µg/mL os extratos do bagaço do fruto verde (AAO% 71,9%,), e casca do caule a 50 µg/mL (AAO% 94%) com CE50 23,7 µg/mL. Os extratos das folhas, casca do caule, bagaço do fruto maduro e bagaço do fruto verde apresentaram CIM de 100 µg/mL contra bactérias e fungos patogênicos multirresistentes.

Antibacterial Potency of Medicinal Plants including Artemisia annua and Oxalis corniculata against Multi-Drug Resistance E. coil.

Antibacterial activity of ethanolic and aqueous extracts of two medicinal plants including Oxalis corniculata (EtOc, AqOc) and Artemisia annua (EtAa, AqAa) as well as A. annua essential oil (EoAa) was investigated on multi-drug resistance (MDR) E. coli. Microdilution and agar well diffusion methods were used to determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) as well as the inhibition zone. The phytconstituents of these products were analyzed using Reverse-phase High- performance liquid chromatography (RP-HPLC) and gas chromatography-mass spectrometry (GC-mass). The order of bacteriostatic and bacteriocide rate of the products can be shown as follows: EoAa>AqOc>EtAa = AqAa>EtOc, but the bactericidal effect of A. annua extracts is higher than of O. corniculata based on the MIC/MBC ratio and the order is as follows: EoAa>EtAa = AqAa>EtOc>AqOc. The most potent product, i.e. EoAa with a 56.7% inhibition of all isolates, has the potential to substitute 13 used antibiotics including oxacillin, amoxicillin, ampicillin, amoxicillin-clavulanic acid, tetracycline, streptomycin, ciprofloxacin, ceftriaxone, cefazolin, cefuroxime, cefotaxime, ceftazidime and cefixime (P <0.05). Different terpenoids were detected and measured in EoAa and catechin flavonoids in extracts of both plants, quercetin in extracts of O. corniculata but it was only possible to detect chlorogenic acid polyphenol in AqAa. Due to the antibacterial activities of the studied products, more effective than some antibiotics and their edible consumption, these products can be suggested as an alternative to some antibiotics and food preservatives to fight against MDR E. coli.

Effect of plant origin and phenological stage on the allelopathic activity of the invasive species Oxalis pes-caprae.

PREMISE: Invasion processes involve several mechanisms, some of which have received little attention. Allelopathy has been invoked as an invasion driver according to the novel weapon hypothesis (NWH), and polyploidization can also be an important factor for invasion success. However, very few studies have addressed both topics together. We analyzed the allelopathic effect of the polyploid Oxalis pes-caprae, an invader in mediterranean-climate areas worldwide, from different origins and ploidy levels (native: South Africa; invaded: Chile, Australia, California, and the Mediterranean Basin) on Lactuca sativa as a model species. METHODS: We measured seed germination, initial plant height, and aboveground and belowground biomass of Lactuca grown in field soil mixed with Oxalis material and with or without activated carbon in a common garden experiment. We performed the experiment twice, when Oxalis was vigorous and when senescent. RESULTS: Vigorous plants of Oxalis tended to reduce Lactuca germination, but both vigorous and senescent Oxalis plants increased Lactuca biomass, probably due to an increase in nutrients provided by plant material. The highest increase in Lactuca traits occurred with Oxalis plants from the Iberian Peninsula. Allelopathy only happened when Oxalis was senescent and was especially strong with plants from Chile. CONCLUSIONS: Although we did not find broad evidence for the NWH considering all areas together, we reported differences in the allelopathic potential of Oxalis plants depending on their origin. These results highlight the independent evolution of invasiveness traits in distant introduced ranges and the importance of the invaders' origin when testing hypotheses about invasion drivers.

Relationships among molecular, physicochemical and digestibility characteristics of Andean tuber starches.

This study aimed to determine and correlate the physicochemical, thermal, pasting, digestibility and molecular characteristics of native starches, such as mashua (Tropaeolum tuberosum R. and P.), oca (Oxalis tuberosa Mol.), and olluco (Ullucus tuberosus C.), which were extracted via successive washing and sedimentation. The morphology of native starches was determined by scanning electron microscopy, granule size distribution, thermal properties, pasting properties, X-ray diffraction (XRD), amylopectin chain-length distribution and amylose and amylopectin molecular weights. Mashua starch was smaller in size than oca and olluco starches. Moreover, the granules of mashua starch were round in shape, whereas those of oca and olluco starches were ellipsoidal in shape. The B XRD spectra showed similar profiles for the three Andean tuber starches. Mashua and olluco starches exhibited the lowest gelatinization temperatures and enthalpy values, and olluco amylopectin exhibited a longer chain length than mashua and oca starches. The resistant starch of gelatinized and ungelatinized samples exhibited a positive and strong correlation with the molecular properties of amylose and amylopectin, gelatinization enthalpy and molecular order.

Stabilisation of betalains and phenolic compounds extracted from red cactus pear (Opuntia ficus-indica) by spray and freeze-drying using oca (Oxalis tuberosa) starch as drying aid.

The objective of this work was to evaluate the stabilisation of betalains and phenolic compounds extracted from red cactus pear by spray and freeze-drying. After hydroethanolic extraction and partial solvent removal under reduced pressure, the highly coloured extracts were enriched with oca starch and maltodextrin as drying aids in different ratios (100:0, 70:30, and 50:50, oca starch: maltodextrin) prior to spray and freeze-drying. The obtained microencapsulated extract powders were characterised by moisture content, hygroscopicity, solubility and morphology. In addition, the stability of the encapsulated betalains and phenolics was evaluated during storage at room temperature for 105 days. All microcapsules showed high retentions of betacyanins (69.9-86.5% after 105 days), betaxanthins (72.2-81.9%), phenolic compounds (46.5-63.5%) and antioxidant capacity (60.1-64.9%, FRAP method; 49.7-57.5%, ABTS method). The system with 70:30 starch:maltodextrin ratio as drying aids showed the highest values of retention regarding the polyphenol content (63.5%), antioxidant capacity (64.9% to FRAP method) and betacyanin content (86.5%), as well as a low degradation rate constant of betacyanins (1.23 × 10-3 days-1) and a long half-life (563 days). Oca starch used alone or in combination with maltodextrin has been shown to work adequately as a microencapsulating agent and stabilizer of pigments and antioxidants derived from red cactus pear.

Phytochemical characterization, antioxidant potential and antimicrobial activity of Averrhoa carambola L. (Oxalidaceae) against multiresistant pathogens.

The objective of this work was to perform the phytochemical characterization, to determine total phenols, antioxidant (AAO%) and antimicrobial potential of the ethanolic extracts of carambola. The phytochemical study was carried out through a qualitative analysis of the chemical constituents and quantitative determination of the phenol content By the Folin-Ciocalteu test. Qualitative and quantitative antioxidant tests were performed using the DPPH method (2,2 diphenyl-1-picryl-hydrazila) and iron reduction (FRAP). The minimum inhibitory concentration (MIC) was determined by microdilution in 96-well plates. The presence of pyrogallic tannins, steroids and saponins has been identified. The highest total phenol content, quantified in the samples, was found in the stem bark (0.0866 mgEAG/g) and in the fruit (0.0734 mgEAG/g). In the antioxidant evaluation, the extracts of the green fruit bagasse (AAO% 71.9%,) and stem bark at 50 µg/mL (AAO% 94%) with CE50 23.7 µg/mL. Leaf extracts, stem bark, ripe fruit bagasse and green fruit bagasse presented MICs of 100 µg/mL against multiresistant pathogenic bacteria and fungi.

Invasive Plants: Turning Enemies into Value.

In this review, a brief description of the invasive phenomena associated with plants and its consequences to the ecosystem is presented. Five worldwide invasive plants that are a threat to Portugal were selected as an example, and a brief description of each is presented. A full description of their secondary metabolites and biological activity is given, and a resume of the biological activity of extracts is also included. The chemical and pharmaceutical potential of invasive species sensu lato is thus acknowledged. With this paper, we hope to demonstrate that invasive species have potential positive attributes even though at the same time they might need to be controlled or eradicated. Positive attributes include chemical and pharmaceutical properties and developing these could help mitigate the costs of management and eradication.

Impact of Invasive Bees on Plant-Pollinator Interactions and Reproductive Success of Plant Species in Mixed Nothofagus antarctica Forests.

Invasive social bees can alter plant-pollinator interactions with detrimental effects on both partners. However, most studies have focused on one invasive bee species, while the interactions among two or more species remain poorly understood. Also, many study sites had a history of invasive bees, being hard to find sites with historical low abundances. In Patagonia, Bombus ruderatus (F.) invasion begun in 1993 and B. terrestris (L.) in 2006. Though honey bees (Apis mellifera L.) introduction started in 1859, their density is still low in some parts. By experimentally increasing honey bee densities, we evaluated the effect of honey bees and bumblebees floral visitation on native pollinator floral visitation, pollen deposition, and reproductive success of three plant species in mixed Nothofagus antarctica forests of northern Patagonia: Oxalis valdiviensis, Mutisia spinosa and Cirsium vulgare. Our results show that exotic bees became the main floral visitors. No negative association was found between invasive bee and native pollinator visitation rates, but there was evidence of potential competition between honey bees and bumblebees. Floral neighborhood diversity played an important role in pollinator behavior. Conspecific pollen deposition was high for all species, while deposition of heterospecific pollen was very high in M. spinosa and C. vulgare. Not as expected, honey bees visitation rate had a negative effect on heterospecific pollen deposition in C. vulgare. For O. valdiviensis, exotic visitation rates increased conspecific pollen deposition, which was positively related to reproductive success. Although exotic bees became main floral visitors, their contribution to reproductive success was only clear for one species.

Seed ejection mechanism in an Oxalis species.

With millions of years' evolution, plants and fungi have developed a variety of ballistic dispersal structures for seeds or spores. One typical example is the catapult of an Oxalis sp., which can realize a consecutive seed ejection by triggering only one seed. If the protrusion on an aril, a specialized outgrowth covering a seed, is disturbed, cracks would occur and cause the opening of the aril. Subsequently, the whole aril snaps and transforms its stored strain energy to eject the inside seed with an optimal launching angle. Once the first seed is triggered, its curly aril will contact the next seed's protrusion and induce its firing. This chain effect will further trigger the remaining seeds in turns, within 0.1 s. Inspired by this phenomenon, we invented a bionic ejection device to launch projectiles with high efficiency. This exploration is promising for a number of applications, such as drug delivery and oil displacement.