Search Results (432)

Trials were carried out to investigate the effects of light and temperature on C. rotundus seeds and tubers under two conditions: (i) in vitro and (ii) after sowing in soil. In the latter, seedling emergence was evaluated after sowing at increasing depths in different soil textures. While dormancy was evident in over 50% of the seeds, which also required light for germination, in contrast, tubers showed a significantly shorter period of dormancy that was independent of light. Seed burial strongly hindered seedling emergence, showing an “active” seed bank only in the shallowest soil layer (few mm). In contrast, tubers showed a marked ability to emerge from a depth exceeding 40 cm. Emergence capacity was found to be proportional to the size of the tubers, attributable to the greater energy reserves needed during autotrophic pre-emergence growth. Seedling emergence from both seeds and tubers, sown at increasing depths, was inhibited to a greater extent in a clay soil texture. A lower inhibitory effect was reported for sandy soils. Tuber vitality was significantly reduced or eliminated within a few days from progressive drying following exposure to solar rays during summer periods. Finally, the data were discussed within the context of planning the agronomic management of C. rotundus, in terms of soil tillage modalities, to ensure sustainable control of this strongly invasive and persistent weed. Full article

The aim of this study was to evaluate the effectiveness of 2.45 GHz microwave application in inhibiting the germination of Portulaca oleracea seeds. Four different soil substrate types were used to establish whether their different properties and composition might influence the microwave heating and inhibition of the seed germination process. Our results show the efficacy of the treatments and suggest the fundamental importance of defining specific microwave treatment protocols to be applied to the affected soil substrate. In this study, we report complete inhibition of germination of P. oleracea seeds in four exposed soil substrates and propose that microwave application could be integrated into an agricultural management system to control a weed such as P. oleracea, which is widespread in many areas of the world. The microwave treatment may represent an ecological and innovative solution that contributes to reducing the dependence on chemical herbicides and promotes greater agricultural sustainability. Full article

Amaranthus palmeri is an aggressive, highly invasive weed that thrives across a wide range of adverse environments worldwide; nevertheless, the mechanisms underlying its rapid expansion remain largely unstudied. Glutathione peroxidase (GPX) is a crucial enzyme within the antioxidant defense system, belonging to the phylogenetic conserved family of oxidoreductases present in all living organisms. Despite its significance, the role of GPX in A. palmeri has not been reported. This study identified eight GPX genes (ApGPXs) in A. palmeri through comprehensive bioinformatics and gene expression analyses. The research examined the characteristics, evolutionary relationships, chromosomal mapping, gene structure, subcellular localization, conserved motifs, and cis-acting elements of these genes, as well as their evolutionary conserved functions in relation to Arabidopsis thaliana GPXs and RT-qPCR analysis under various stress conditions. The ApGPXs were distributed across scaffolds (2, 4, and 12) of the A. palmeri genome. Phylogenetic analysis grouped GPX genes into four subgroups, and conserved motifs were found within certain phylogenetic subgroups. We identified Actin8 as the most stable internal reference gene for A. palmeri under diverse stress conditions. Gene expression analysis revealed that ApGPXs participate in both early and late regulatory responses to oxidative stress induced by NaCl, high temperature, osmotic pressure, and glufosinate ammonium. The Arabidopsis GPX mutant (AT4G31870) exhibited a stronger flg22-induced oxidative burst than the wild type, and qPCR confirmed that AtGPXs contribute significantly to glufosinate ammonium stress responses. Evolutionary analysis found high sequence similarity between ApGPX4 and AT1G63460, as well as ApGPX3 and AT4G11600. Also, ApGPX3 and AT4G11600 shared similar expression patterns under glufosinate ammonium stress. This research presents the first gene family study in A. palmeri and provides foundational insights for future studies in this economically critical species. Our findings establish a framework for mitigating A. palmeri’s impact on crop production and exploring ApGPXs in developing herbicide- and stress-tolerant cultivars. Full article

Acetolactate synthase (ALS) is an important enzyme in plant branched-chain amino acid biosynthesis and the target of several major herbicide classes. Despite its agronomic importance, the role of ALS genes in stress adaptation in the invasive weed Amaranthus palmeri remains unstudied. In this study, four ApALS genes with high motif conservation were identified and analyzed in A. palmeri. Phylogenetic analysis classified ApALS and other plant ALS proteins into two distinct clades, and the ApALS proteins were predicted to localize to the chloroplast. Gene expression analysis demonstrated that ApALS genes are responsive to multiple stresses, including salt, heat, osmotic stress, glufosinate ammonium, and the ALS-inhibiting herbicide imazethapyr, suggesting roles in both early and late stress responses. Herbicide response analysis using an Arabidopsis thaliana ALS mutant (AT3G48560) revealed enhanced imazethapyr resistance, associated with higher chlorophyll retention. Furthermore, high sequence homology between AT3G48560 and ApALS1 suggests a conserved role in protecting photosynthetic function during herbicide stress. This study provides the first comprehensive analysis of the ALS gene family in A. palmeri and offers important insights into its contribution to stress resilience. These findings establish a vital foundation for developing novel strategies to control this pervasive agricultural weed and present potential genetic targets for engineering herbicide tolerance in crops. Full article

Water hyacinth is an invasive weed that can valorize through the production of hydrolytic enzymes via solid-state culture. This study explores the application of Trichoderma harzianum in producing xylanases and endoglucanases on water hyacinth beds. Laboratory-scale packed-bed column bioreactors (PBCBs) with a capacity of 8 grams of dry mass (g_dm) were used to evaluate the effects of temperature (28–36 °C) and initial moisture content (65–80%) on microbial growth and enzyme production. High yields of biomass and enzymes were produced at 30 °C. Moreover, xylanase activity was enhanced in cultures with a moisture content of 65% (~71.24 U/g_dm), and endoglucanase activity at 75–80% moisture (~20.13 U/g_dm). The operational conditions identified for xylanase production were applied to 6 L bench-scale cross-flow internally stirred bioreactors, packed to 40% capacity with 450 g_dm. Two stirring regimes were tested: intermittent and continuous. The results showed that continuous stirring promotes both microbial growth and xylanase activity. In fact, xylanase activity in continuous stirring conditions was comparable to that achieved in PBCBs. Consequently, continuous stirring enables a 56-fold increase in bioreactor capacity without compromising xylanase production. The approaches developed in this study can support the design of large-scale bioprocesses for the valorization of water hyacinth. Full article

Potential sources of chlorophyll, widely used in the pharmaceutical and food industries, could be invasive species and weeds. The aim of the study was to estimate the effect of vegetation period and leaf age on changes of chlorophyll and carotenoid contents in leaves of six widespread plant species of four different families, as well as in the weed Urtica dioica as a “comparative” species. Plants were growing under the same environmental conditions, and chlorophylls and carotenoids were analyzed spectrophotometrically every two weeks from May to September. Average total chlorophyll (a + b) content only in leaves of Lamium album and Aegopodium podagraria was lower than in Urtica dioica and significantly differed from their content in Leonurus cardiaca and Agrimonia eupatoria. Total chlorophyll (a + b) content in leaves of common native Pastinaca sativa and very invasive Solidago canadensis was also higher or very similar to that of Urtica dioica. The highest amount of green pigments in all species was found at the budding and/or flowering period. Unlike other species, variation of total chlorophyll (a + b) in Leonurus cardiaca was little, and chlorophyll a/b ratio was lower than 2:1 during the vegetation period. In contrast to total chlorophyll (a + b), total carotenoid was higher in young leaves. Full article

Ambrosia artemisiifolia is one of the invasive plants found in Europe. Research into this species is important not only in terms of environmental consequences but also in terms of human health, as it is an allergenic weed. Here, the genetic variability in the accessions of common ragweed from three localities of the Slovak Republic was analysed. A Bet v 1-based amplified polymorphism was applied for degenerated and non-degenerated primers. Three of the five primer variants were able to distinguish all analysed accessions, and two primer combinations were able to distinguish two accessions in the same amplified fingerprint profile from Kicsina. Using the BBAP technique, between of 1 to 16 amplicons were obtained per 1 genotype of common ragweed within a range of 68 to 3266 base pairs. Using two of the BBAP primer variants, unique fragments were obtained. The results indicate that the outcrossing among Slovak genotypes of Ambrosia artemisiifolia L. as non-specific BBAP profiles of individual analysed localities was observed. Full article

Due to the increasing complexity of industrial systems, fault detection hinders the continuity of productivity. Also, many methods in industrial systems whose complexity increases over time have a mechanism based on human intervention. Therefore, the development of intelligent systems in fault detection is critical.. Avoiding false alarms in detecting real faults is one of the goals of these systems. Modern technology has the potential to improve strategies for detecting faults related to machine components. In this study, a hybrid approach was applied on two different datasets for fault detection. First, in this hybrid approach, data is given as input to the artificial neural network. Then, predictions are obtained as a result of training using the ANN mechanism with the feed forward process. In the next step, the error value calculated between the actual values and the estimated values is transmitted to the feedback layers. IWO (Invasive Weed Optimization) optimization algorithm is used to calculate the weight values in this hybrid structure. However the IWO optimization algorithm is designed to be initialized with fractal-based weighting. By this process sequence, it is planned to increase the global search power without getting stuck in local minima. Additionally, fractal-based initialization is an important part of the optimization process as it keeps the overall success and stability within a certain framework. Finally, a testing process is carried out on two separate datasets supplied by the Kaggle platform to prove the model’s success in failure detection. Test results exceed 98%. This success indicates that it is a successful model with high generalization ability. Full article

Accurate normalization is crucial for reliable gene expression quantification and depends on stably expressed housekeeping genes (HKGs) as internal controls. However, HKGs expression varies with developmental stage, tissue type, and treatments, potentially introducing bias and compromising data accuracy. Thus, validating candidate reference genes under defined conditions is essential. Reynoutria, also known as giant Asian knotweeds, is a Polygonaceae family genus of several medicinal plants producing a diverse array of specialized metabolites of pharmacological interest. Outside their native range, these plants are also noxious invasive weeds, causing significant environmental and economic threats. Research on stable reference genes in these species is limited, with a primary focus on R. japonica. To enable accurate gene expression analysis related to specialized metabolism and natural product biosynthesis, we aimed to identify the most stable reference genes across the most common species: R. japonica Houtt., R. sachalinensis (F. Schmidt) Nakai, and their hybrid—R. × bohemica Chrtek & Chrtková. In this study, we evaluated twelve candidate HKGs (ACT, TUA, TUB, GAPDH, EF-1γ, UBQ, UBC, 60SrRNA, eIF6A, SKD1, YLS8, and NDUFA13) across three tissue types (rhizomes, leaves, and flowers) from three Reynoutria species sampled at peak flowering. Primer specificity and amplification efficiency were confirmed through standard-curve analysis. We assessed expression stability using ΔCt, geNorm, NormFinder, and BestKeeper, and generated comprehensive rankings with RefFinder. Our integrated analysis revealed organ- and species-dependent stability differences, yet identified up to three reference genes suitable for interspecific normalization in Reynoutria. This represents the first systematic, comparative validation of HKGs across closely related knotweed species, providing a robust foundation for future transcriptomic and functional studies of their specialized metabolism and other biological processes. Full article

Invasive weeds pose a growing threat to global biodiversity, ecosystem stability, and agricultural productivity with significant ecological and economic consequences. In Iran, the rapid spread of invasive species such as Boreava orientalis, Azolla spp., Ibicella lutea, Physalis divaricata, Picnomon acarna, Cynanchum acutum, Vicia hyrcanica, Eichhornia crassipes, and Ambrosia psilostachya has severely affected native ecosystems, disrupted ecological processes, and threatened food security. These species exhibit aggressive traits such as rapid maturity, high reproductive rates, seed dormancy, and allelopathy that enable them to outcompete native species and successfully invade and dominate delicate habitats. Despite their documented impacts, a critical gap remains in understanding their biology, ecology, and management, particularly in understudied regions like Iran. This review synthesizes current knowledge on major invasive weeds affecting Iranian agroecosystems, with a focus on their ecological impacts and the urgent need for sustainable management strategies. It presents an integrated framework that combines ecological, biological, and management perspectives to address invasiveness, particularly in highly adaptable species like B. orientalis and A. psilostachya. This review highlights the critical role of interdisciplinary collaboration, advanced technology, and community involvement in developing effective strategies. It offers practical guidance for researchers, policymakers, and agricultural stakeholders, serving as a model for managing invasive species in other vulnerable regions. Ultimately, it supports global efforts to safeguard biodiversity, improve crop productivity, and strengthen ecological resilience against the growing threat of invasive species. Full article

Global trade facilitates multiple introductions of alien species, yet the role of genetic admixture between divergent lineages in driving invasion success remains debated. Here, we address this question by analyzing dynamic genetic changes across invasion stages in the dioecious weed Amaranthus palmeri, introduced to China from North and South America. Combining chloroplast phylogeography with nuclear genetic analyses, we systematically investigated genetic changes in populations at casual, naturalized, invasive, and dispersal stages. Initial casual populations originated from distinct North and South American lineages, but all established populations (naturalized, invasive, dispersal) retained only North American haplotypes. South American genetic introgression decreased progressively during invasion (from 34% in naturalized to 3% in dispersal populations), accompanied by declining inbreeding coefficients. Established populations exhibited high inter-population crosses within the North American lineage (54–60%), maintaining genetic diversity and overcoming bottlenecks. Our findings demonstrate that invasion success in A. palmeri may be driven by gene flow within the North American lineage, rather than admixture between divergent lineages. These findings enhance our understanding of the genetic mechanisms underpinning plant invasions, highlighting lineage-specific management as a critical strategy for controlling invasive populations. Full article

Using multiple species in native plant communities may improve control efficiency compared with single-species use. We conducted field investigations to assess the effects of Artemisia argyi, Portulaca oleracea, and their mixtures on the growth and reproduction of Mikania micrantha, followed by a greenhouse de Wit replacement series to compare different combinations of M. micrantha, A. argyi, and P. oleracea in terms of multispecies competition, phytoallelopathy, and photosynthesis. Field investigation showed that compared with M. micrantha monoculture (Group D), aboveground biomass, total stem length, flower biomass, inflorescence biomass, seed biomass, and seed number of M. micrantha increased in the P. oleracea community (Group B), though only seed number was significantly higher (p < 0.05). In contrast, in the A. argyi community (Group A) and the mixed community of A. argyi and P. oleracea (Group C), all these indicators decreased significantly (p < 0.05), in the order: Group C < Group A < Group D < Group B. This indicates that the mixed community (Group C) most strongly suppressed M. micrantha growth and reproduction. The effects of A. argyi, P. oleracea, and their mixture on the growth of M. micrantha in the greenhouse experiments mirrored the trends observed in field investigations. Calculated indices (relative yield, relative yield total, competitive balance index, and change in contribution) of A. argyi, P. oleracea, and their mixed population on M. micrantha demonstrated a higher competitive ability and higher influence of the combination of the two species compared with either A. argyi or P. oleracea alone. The interspecific phytoallelopathy experiment demonstrated strong allelopathic potential of A. argyi versus M. micrantha (p < 0.05) but showed no significant effect on P. oleracea. The net photosynthetic rate (Pn) of M. micrantha was generally lower in communities with both competitors compared with single-species communities. Our results suggest that, compared with a single plant population, the mixed population of A. argyi and P. oleracea exhibited a markedly enhanced ecological control capability through increased relative competitive ability, strengthened allelopathic inhibition, and markedly reduced photosynthetic efficiency of M. micrantha. Full article

The role of rhizosphere bacteria in facilitating plant invasion is increasingly acknowledged, yet the influence of specific microbial functional traits remains insufficiently understood. This study addresses this gap by isolating two bacterial strains, Bacillus sp. ScRB44 and Pseudomonas sp. ScRB22, from the rhizosphere of the invasive weed Solidago canadensis. We assessed their nitrogen utilization capacity and indoleacetic acid (IAA) production capabilities to evaluate their ecological functions. Our three-stage experimental design encompassed strain promotion, nutrient stress, and competition phases. Bacillus sp. ScRB44 demonstrated robust IAA production and significantly improved the nitrogen utilization efficiency, significantly enhancing S. canadensis growth, especially under nutrient-poor conditions, and promoting a shift in biomass allocation toward the roots, thereby conferring a competitive advantage over native species. Conversely, Pseudomonas sp. ScRB22 exhibited limited functional activity and a negligible impact on plant performance. These findings underscore that the ecological impact of rhizosphere bacteria on invasive weeds is closely linked to their specific growth-promoting functions. By enhancing stress adaptation and optimizing resource allocation, certain microorganisms may facilitate the establishment of invasive weeds in adverse environments. This study highlights the significance of microbial functional traits in invasion ecology and suggests novel approaches for microbiome-based invasive weed management, with potential applications in agricultural soil health improvement and ecological restoration. Full article

Common ragweed, Ambrosia artemisiifolia (Asteraceae), is an invasive weed that causes problems in cropping systems and to human health both in its native range in North and Central America and the introduced range in Europe, Asia, Africa, and Australia. Ophraella communa, an herbivorous chrysomelid beetle from North America, was accidentally introduced into East Asia and Europe, where it significantly reduces weed populations and pollen production. Despite extensive research on its host specificity and risk assessment, the potential environmental risk of this biological control agent in southeastern Central Europe, one of the most heavily invaded areas by A. artemisiifolia, remains to be determined. This literature review attempts to summarize the results of host-range testing conducted so far and identifies plant taxa native to southeastern Central Europe that have not been tested yet. The results suggest that the host range of O. communa is not yet entirely clear, but may include some plant species from the tribes Heliantheae, Inuleae, Anthemideae, Cardueae, Astereae, and/or Coreopsideae. So far, only some of the 21 genera from those tribes with species in southeastern Central Europe have been tested. We therefore suggest further host specificity studies with representatives of these plant genera to fully assess the potential non-target risks by O. communa in agricultural and natural habitats. Full article

Common ragweed (Ambrosia artemisiifolia L.) has been identified as one of the most harmful invasive weed species in Europe due to its allergenic pollen and competitive growth in diverse habitats. In the first part of this review [Common Ragweed—Ambrosia artemisiifolia L.: A Review with Special Regards to the Latest Results in Biology and Ecology], its biological characteristics and ecological behavior were described in detail. In the current paper, control strategies are summarized, focusing on integrated weed management adapted to the specific habitat where the species causes damage—arable land, semi-natural vegetation, urban areas, or along linear infrastructures. A range of management methods is reviewed, including agrotechnical, mechanical, physical, thermal, biological, and chemical approaches. Particular attention is given to the spread of herbicide resistance and the need for diversified, habitat-specific interventions. Among biological control options, the potential of Ophraella communa LeSage, a leaf beetle native to North America, is highlighted. Furthermore, innovative technologies such as UAV-assisted weed mapping, site-specific herbicide application, and autonomous weeding robots are discussed as environmentally sustainable tools. The role of legal regulations and pollen monitoring networks—particularly those implemented in Hungary—is also emphasized. By combining traditional and advanced methods within a coordinated framework, effective and ecologically sound ragweed control can be achieved. Full article