Strong Competitive Ability Research Articles

Comparison of leaf anatomical structure and photosynthetic characteristics between weedy rice and cultivated rice at the seedling stage

To explore the internal factors related to the strong growth and competitive ability of weedy rice during the seedling period, we collected two biotypes of Japonica weedy rice from Northeast China, four biotypes of Indica weedy rice from Eastern China and Southern China, and two biotypes of cultivated rice, Zhendao-8 (ZD-8) and Shanyou-63 (SY-63), which were used as controls in a pot experiment. Under homogeneous garden planting conditions, we measured the vascular bundle size (VBS), vascular bundle number (VBN), leaf thickness (LT), air cavity size (ACS), stomatal size (SS), stomatal density (SD), net photosynthetic rate (Pn) and stomatal conductance (Gs) of the weedy and cultivated rice biotypes. A comprehensive analysis was performed to explore the correlation between the seedling leaf structure and the photosynthetic indices of the biotypes. The results showed the following: (1) At the seedling growth stage, the leaf structure parameters of weedy rice were significantly greater than those of ZD-8 and SY-63. (2) The Pn and Gs of weedy rice were significantly positively correlated with VBS, VBN, LT, ACS, and SD. Thus, the leaf structural features of weedy rice provide the anatomical basis for the stronger Pn and establish a strong competitive physiology at the seedling stage. Therefore, the prevention and elimination of weedy rice should start at the seedling stage.

An atoxigenic Aspergillus flavus PA67 from Shandong province exhibits potential in biocontrol against toxigenic Aspergillus flavus, Sclerotium rolfsii, and Fusarium proliferatum

Peanuts and corn are susceptible to various soil-borne fungi, leading to significant economic losses. Atoxigenic Aspergillus flavus have been widely used as biocontrol agents for managing aflatoxin contamination because of their minimal environmental impact, strong competitive ability, and sustained inhibition effect. After multiple identifications and cluster amplification pattern (CAP) analysis, three atoxigenic A. flavus PA04, PA10 and PA67 were isolated from peanut samples in Shandong Province, which can reduce aflatoxin levels by up to 90 %. Our study revealed that atoxigenic A. flavus also competed vigorously with Sclerotium rolfsii and Fusarium proliferatum for nutrition and space, achieving notable inhibition rates of up to 90.4 % and 90.6 %, respectively. The supernatants of atoxigenic A. flavus also inhibited the growth of S. rolfsii and F. proliferatum, with PA67 demonstrating the most significant effect. Whole genome sequencing revealed that PA67 contains multiple glycoside hydrolases and metabolites with antifungal activity. The kojic acid production of PA67 was higher than that of PA04 and PA10, reaching 17.48 g/L, which has a significant inhibition on sclerotia germination. PA67 supernatant significantly inhibited the hyphae growth of S. rolfsii and F. proliferatum, and down-regulated genes related to sclerotia and fumonisin formation. This study demonstrates the biocontrol potential of PA67 against three soil-borne fungi and is the first investigation of atoxigenic A. flavus to inhibit S. rolfsii and F. proliferatum.

Prediction of potential invasion of two weeds of the genus Avena in Asia under climate change based on Maxent

Avena sterilis L. (A. sterilis) and Avena ludoviciana Dur. (A. ludoviciana) are extremely invasive weeds with strong competitive ability and multiple transmission routes. Both species can invade a variety of dryland crops, including wheat, corn, and beans. Asia, as the world's major food-producing continent, will experience significant losses to agricultural production if it is invaded by these weeds on a large scale. This study used the MaxEnt model and ArcGIS to map the distribution of suitable habitats of the two species in Asia under climate change conditions. The constructed model comprised four levels, with a total of 25 index-level indicator factors used to evaluate the invasion risk of the two species. The results showed that the distribution of suitable habitats for both Avena species was highly dependent on precipitation and temperature. Under climate warming conditions, although overall the total suitable area is predicted to decrease compared to the current period, there are still moderately or highly suitable areas. Asian countries need to provide early warning for areas with significant increases in moderate and highly suitable zones for these two species of weeds under the background of climate change. If there is already an invaded area or if the suitability of the original area is increased, this should be closely monitored, and control measures should be taken to prevent further spread and deterioration.

Synthesis of a low-temperature demulsifier with dual-hydrophobic chains through a simple low-temperature process

The extraction of crude oil generates a significant volume of stable emulsions that can lead to various adverse effects in industrial extraction processes. Therefore, emulsion demulsification is a crucial step. In this paper, PGDA, a low-temperature W/O demulsifier with double hydrophobic chains, was synthesized from poly(ethylene glycol) diacrylate by a simple low-temperature process. The structure of PGDA was analyzed by FTIR and 1H NMR, and the demulsification performance was evaluated by a bottle-testing method. The results demonstrated that PGDA, at a concentration of 500 mg/L, achieved a demulsification efficiency of 100 % under low-temperature conditions (45 °C) over a 5-hour period. Furthermore, it also showed good demulsifying performance in wide pH range (6–10) and high salinity (100,000 mg/L). In addition, the possible mechanism of demulsification of PGDA was investigated by zeta potential, interfacial tension, and three-phase contact angle, etc. PGDA showed strong competitive adsorption ability with asphaltenes at the interface. PGDA has the ability to navigate rapidly to the oil–water boundary and displace the native surfactants there, thus destabilizing the emulsion and thus promoting the separation of oil and water. PGDA by virtue of the simple synthesis process, low demulsification temperature and high efficiency are of practical application.

Germination Ecology and Ecology-based Management of Fimbristylis miliacea (L.) in Lowland Rice: A Review

Fimbristylis miliacea (L.) Vahl, commonly referred to as globe fringerush, member of the Cyperaceae family, is a significant and widespread sedge weed in rice cultivation. This C4 plant is characterized by its tall, annual or perennial growth, featuring a fibrous root system and smooth stems, often producing vigorous tillers reaching heights of 80-90 cm. Seedlings of F. miliacea typically emerge shortly after rice is planted, with flowering occurring within about a month, capable of producing a second generation within the same growing season. Found extensively throughout tropical regions, especially in lowlands, F. miliacea thrives in environments such as rice fields, shallow water along ditches, and streams, notably prevalent across South and Southeast Asia, as well as Australia. This weed presents enduring challenges across diverse agro-ecosystems due to its various ecotypes, prolific seed production, rapid germination, vigorous growth, strong competitive abilities and allelopathic interactions. Temperature is a critical factor significantly influencing seed germination of F. miliacea which exhibits non-deep physiological dormancy. Light is essential for the germination of this weed showing positive photoblastic behaviour. F. miliacea thrives in saturated soils but fails to emerge from depths greater than one cm, emphasizing the importance of shallow tillage to manage weed emergence effectively. Effective weed management hinges on a deep understanding of the factors that favour its emergence and establishment. Adopting the germination ecology-based practices such as tillage, stale seed bed preparation, optimal planting density, water management and nutrient management can significantly improve the management of F. miliacea.

Pemanfaatan Tanaman Gulma Berbunga sebagai Mikrohabitat Musuh Alami Pada Tanaman Kedelai di Lahan Sub Optimal

Pemanfaatan Tanaman Gulma Berbunga sebagai Mikrohabitat Musuh Alami Pada Tanaman Kedelai di Lahan Sub Optimal

Metagenomics reveals the underestimated role of bacteria in the decomposition of downed logs in forest ecosystems

Downed logs are important structural and functional elements in the material flow of global forest ecosystems. They provide a rich natural substrate resource for microorganisms; however, current laboratory-based methods cannot fully elucidate the complex process of microbial decomposition of downed logs. Therefore, our study investigated the microbial community structure, succession patterns, and underlying environmental factors controlling the decomposition of Pinus tabulaeformis and Quercus aliena var. acuteserrata downed logs at different stages of decomposition in Chinese forest ecosystems. The genomes of the microorganisms present on the logs during different stages were therefore sequenced, and functional genes were annotated and analyzed using the Kyoto Encyclopedia of Genes and Genomes and Carbohydrate-Active enZYmes databases. We found that bacterial abundance was always higher than fungal abundance throughout the decomposition process, reflecting their strong competitive ability. Microbial community structure and function were similar in the early stage (I) and late stages (IV, V) of log decomposition, but those of the middle stages (II, III) differed. With the decomposition of downed logs of Q. aliena var. acuteserrata, there was a fungal succession pattern from Ascomycota to Basidiomycota to Mucoromycetes, but this trend did not occur for P. tabulaeformis. The density, moisture and elemental content of downed logs were the main factors affecting the microbial community. Finally, microbially mediated functions were mainly related to the metabolism of amino acids, carbohydrates and various small molecule carbohydrate enzymes, cellulases, and chitinases in glycoside hydrolases; the taxa sources of the main functions were primarily Proteobacteria and Firmicutes bacteria, reflecting the functional importance of bacteria in the process of downed log decomposition. We conclude that bacteria always play an important role in the process of downed log decomposition and that their role may be far underestimated. Therefore, we believe that the next step should be to expand the study of downed log bacteria, to further clarify the ecological functions of the bacteria on downed logs in natural environments and their relationship with fungi, which may help shed light on the complex decomposition process of downed logs.

HBWO-JS: jellyfish search boosted hybrid beluga whale optimization algorithm for engineering applications

Abstract Beluga whale optimization (BWO) algorithm is a recently proposed population intelligence algorithm. Inspired by the swimming, foraging, and whale falling behaviors of beluga whale populations, it shows good competitive performance compared to other state-of-the-art algorithms. However, the original BWO faces the challenges of unbalanced exploration and exploitation, premature stagnation of iterations, and low convergence accuracy in high-dimensional complex applications. Aiming at these challenges, a hybrid BWO based on the jellyfish search optimizer (HBWO-JS), which combines the vertical crossover operator and Gaussian variation strategy with a fusion of jellyfish search (JS) optimizer, is developed for solving global optimization in this paper. First, the BWO algorithm is fused with the JS optimizer to improve the problem that BWO tends to fall into the best local solution and low convergence accuracy in the exploitation stage through multi-stage exploration and collaborative exploitation. Then, the introduced vertical cross operator solves the problem of unbalanced exploration and exploitation processes by normalizing the upper and lower bounds of two stochastic dimensions of the search agent, thus further improving the overall optimization capability. In addition, the introduced Gaussian variation strategy forces the agent to explore the minimum neighborhood, extending the entire iterative search process and thus alleviating the problem of premature stagnation of the algorithm. Finally, the superiority of the proposed HBWO-JS is verified in detail by comparing it with basic BWO and eight state-of-the-art algorithms on the CEC2019 and CEC2020 test suites, respectively. Also, the scalability of HBWO-JS is evaluated in three dimensions (10D, 30D, 50D), and the results show the stable performance of the proposed algorithm in terms of dimensional scalability. In addition, three practical engineering designs and two Truss topology optimization problems demonstrate the practicality of HBWO-JS. The optimization results show that HBWO-JS has a strong competitive ability and broad application prospects.

Sedimentary Vibrio Blooms in the Xisha Islands May Associate with the 2020 Coral Bleaching Event.

Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is known about the distribution and community assembly of coral pathogenic bacteria (e.g., several Vibrio species). We elucidated the distribution pattern and interaction relationships of total bacteria and Vibrio spp. in sediments from the Xisha Islands, which are characterized by their high coverage and diversity of coral resources. Vibrio spp. showed significantly higher relative abundance values in the Xisha Islands (1.00 × 108 copies/g) than in other areas (approximately 1 × 104 to 9.04 × 105 copies/g), indicating that the coral bleaching event of 2020 may have promoted the bloom of vibrios. A spatial shift in community composition was observed between the northern (Photobacterium rosenbergii and Vibrio ponticus) and southern (Vibrio ishigakensis and Vibrio natriegens) sites, accompanied by a clear distance-decay pattern. The spatial distance and coral species (e.g., Acroporidae and Fungiidae) had much greater correlations with the Vibrio community than did environmental factors. However, complex mechanisms may exist in the community assembly of Vibrio spp. due to the large proportion of unexplained variation. Stochastic processes may play an important role, as shown by the neutral model. Vibrio harveyi had the highest relative abundance (77.56%) and niche breadth, compared to other species, and it was negatively correlated with Acroporidae, likely reflecting its strong competitive ability and adverse effects on specific corals. Our study provides insights into the bloom and underlying assembly mechanisms of sedimentary vibrios in the Xisha Islands, thereby contributing to identify the potential indicator of coral bleaching and provide inspiration for the environmental management of coral reef areas. IMPORTANCE Coral reefs exert important roles in maintaining the sustainability of marine ecosystems but decline worldwide due to various drivers, especially pathogenic microorganisms. Here, we investigated the distribution pattern and interactions of total bacteria and Vibrio spp. in the sediments from Xisha Islands during the coral bleaching event of 2020. Our results showed that the abundances of Vibrio (1.00 × 108 copies/g) were high across the whole sites, indicating the bloom of sedimentary Vibrio spp. Coral pathogenic Vibrio species were abundant in the sediments, likely reflecting adverse effects on several kinds of corals. The compositions of the Vibrio spp. were separated by geographical location, which was mainly attributable to the spatial distance and coral species. Overall, this work contributes by providing evidence for the outbreak of coral pathogenic vibrios. The pathogenic mechanism of the dominant species (especially V. harveyi) should be comprehensively considered by laboratory infection experiments in the future.

Roots originating from different shoot parts are functionally different in running bamboo, Phyllostachys glauca

Abstract Running bamboos are a group of clonal plants exhibiting rapid and widespread expansion. They possess two root subsystems, arising from different shoot parts, culm roots and rhizome roots. To date, it remains unclear what the functional differences are between the two root subsystems and what their relation is to the remarkably competitive ability of running bamboos. A typical running bamboo, Phyllostachys glauca, which dominates in a highly heterogeneous habitat of limestone hills, was sampled to compare the morphology, architecture, anatomy, chemical composition, mechanics and nutrient acquisition of the two root subsystems to explore their differences in functional traits. Compared with rhizome roots, culm roots possessed greater tensile strength, modulus of elasticity, stele diameter to root diameter ratio, root tissue density, root length density, rooting depth, basal diameter of shoot‐borne roots and more lignified cells. Culm roots also had a higher phosphorus (P) concentration (>0.4 mg g−1), which was nearly twice that of rhizome roots. By contrast, rhizome roots exhibited a greater specific root area, specific root length, cortex thickness to root radius ratio, total branch order and greater P‐uptake capacity than culm roots. Our findings revealed distinct differences in functional traits between culm roots and rhizome roots in P. glauca. Culm roots are considered to primarily provide anchorage, but also function in resource acquisition and nutrient storage, while rhizome roots mainly play a role in resource acquisition. Except for the anchorage and resource acquisition of culm roots, the extra resource acquisition by rhizome roots and the high concentration of a limiting nutrient (P) in culm roots enhance the performance in a highly heterogeneous habitat which offers a physiological explanation for P. glauca dominating on limestone hills. The functional differentiation between culm roots and rhizome roots provides insight into the mechanism underpinning the remarkable expansion of running bamboos and offers a new perspective to explain the strong competitive ability of clonal plants with dimorphic roots. Read the free Plain Language Summary for this article on the Journal blog.

Changes in plant community assembly from patchy degradation of grasslands and grazing by different-sized herbivores.

Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, that is, gradual formation of degraded patches (hereafter "patchy degradation"). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non-degraded (intact) and patch-degraded (fragmented) grasslands subject to grazing by different-sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over 4 years. Using a null-model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected β-diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non-degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non-degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. SG consistently promoted more stochastic plant community assembly in both non-degraded and patch-degraded grasslands, while CG promoted more stochastic plant community assembly only in the non-degraded state, having no effect in the patch-degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch-degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species-specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts.

The application of sports mechanics principles in physical education

As a special form of physical exercise, physical education has a positive effect on people's physical and mental health development. However, due to the influence of venue and equipment, students' participation is not high and the effect is not satisfactory. Therefore, it is necessary to strengthen physical education and improve teachers' professionalism in order to provide a good training environment for students. Based on this, this paper will analyze the mechanics of strength and endurance movements used by athletes in the process of competition with the basic principles of kinesiology and related theoretical knowledge, and finally propose specific implementation strategies on how to use the laws of mechanics to enhance the skills of athletes, so as to ensure that athletes can give full play to their subjective initiative and maximize their personal value in the competition activities. In order to further improve the overall strength of the athletes, and finally achieve excellent results to obtain the desired results. It is hoped that the research results can provide some reference value for the general physical education teachers, and promote our athletes to have stronger competitive ability and adaptability in the fierce competitive environment, and continuously optimize their own physical training mode.

Species Choice Influences Weed Suppression, N Sharing and Crop Productivity in Oilseed Rape–Legume Intercrops

Increasing crop trait diversity in oilseed rape (OR, Brassica napus L.) cropping systems by introducing frost-sensitive legume species could improve weed suppression and crop productivity. Intercrops and sole crops were compared over two years in the field in Western France. Winter OR was intercropped simultaneously with either spring faba bean (Vicia faba L.) or common vetch (Vicia sativa L.) in a row replacement design without herbicides. Each species was sown at 50% of the recommended sole crop density in alternate rows. Due to the high values of faba bean aboveground traits (height, leaf area, and biomass) and the strong competitive ability for soil N of OR, both species appeared complementary in resource utilization, and thus less soil N and light were available for weeds. The OR–faba bean intercrop was able to reduce weed biomass by 41% compared to the OR–common vetch intercrop. Furthermore, growth and competitive ability of OR for soil N were increased when intercropped with faba bean. Both grain yield and number per plant were three times higher in OR–faba bean intercrops compared to OR sole crops. Under high weed infestation, the presence of faba bean with OR reduced weed aboveground biomass by 35% and weed N accumulation by 11% compared to the OR sole crop. No change was observed in the weed community composition. We observed that a level of aboveground biomass greater than 2 t ha−1 and a soil N uptake at approximately 80 kg ha−1 was needed to reduce biomass and N content of weeds.

Diversity of Endemic Ectomycorrhizae of Humid Forests of South Cameroon

The ecologically important below-ground ectomycorrhizal (ECM) biodiversity of tropical humid forests remain poorly known. Most ECM inventories have been based upon description and identification of fruitbodies with few work on ECM root tips of tropical tree species. Morpho-anatomical descriptions of root tips of 24 ECM Fabaceae/Detarioideae, Uapaca tree species, and Gnetum lianas were conducted in humid forest of South Cameroon. ECM forest clumps were the only resort sites for the more than 30 endemic ECM morphotypes, with apparently no host specificity. Distinguished by four colors – white, yellow, brown, and dark brown – and five textures – smooth, cottony, woolly, spiny and verrucose –, they differed from to the golden yellow coralloïdal Gnetum liana ECM with plectenchymatous mantle. Tree ECM were of monopodial-pinnate or -pyramidal types with external felt prosenchyma mantles shielded with abundant rhizomorphs, emanating hyphae and variously shaped cystida with clamp connections. These ECM fungal attributes may confer ECM associations with strong competitive abilities to strive at best on prevailing nutrient-poor acid soils and harsh conditions, thus better explaining tropical monodominance. Yet, much research is still needed to determine the role of below-ground ECM biodiversity on structure and functioning of tropical humid forests of the Congo basin.

Woody invaders are more highly colonized by arbuscular mycorrhizal fungi than congeneric native species.

Invasive species tend to possess acquisitive plant traits that support fast growth and strong competitive ability. However, the relevance of symbioses with arbuscular mycorrhizal fungi (AMF) to the fast growing, acquisitive strategy of invasive species is still unclear. We measured AMF colonization in roots of five congeneric pairs of invasive and native eastern North American woody species (10 species total; 4 lianas, 6 shrubs) that were grown in a monoculture common garden experiment in Syracuse, NY. We then examined the relationships of AMF colonization to above and belowground traits of these species. Total AMF colonization and arbuscule colonization were greater in invasive compared to native woody species, a pattern that was more distinct in congeneric shrubs than congeneric lianas. The level of AMF colonization was also positively correlated with traits indicative of rapid plant growth and nutrient uptake. The concordance of a resource-acquisitive strategy with higher AMF colonization suggests that symbioses with AMF may be part of the strategy by which invasive woody plants of eastern North America are able to maintain fast growth rates and outcompete their native counterparts.

N-Induced Species Loss Dampened by Clipping Mainly Through Suppressing Dominant Species in an Alpine Meadow.

Nitrogen addition and clipping can exert substantial impact on species diversity but their interactions and the underlying mechanisms still remain unclear. Resource competition theory holds that sufficiently strong competitive ability of dominant species can lead to the losses of subordinate species through competitive exclusion, while niche differentiation theory suggests that the persistence of subordinate species in competitive systems can be promoted by guaranteeing positive growth rates of rare species. Taking advantage of a field experiment with nitrogen addition (10 g N m–2 year–1) and different clipping intensities (2, 15, and 30 cm) treatments in a Tibetan alpine meadow across 2015–2020, we assessed the relative importance of competitively dominant species and niche differentiation in driving species diversity changes via using community weighted mean (CWM) and variation coefficient of nearest neighbor distance (CV_NND) of functional traits including height, specific leaf area (SLA) and leaf dry matter content (LDMC). We show that nitrogen enrichment drove a strong plant diversity loss (P < 0.001). Clipping at different intensities had little effect on species diversity, but it can reduce the N-induced diversity loss. Nitrogen addition and clipping caused changes in community diversity were mainly indirectly attributed to their effects on community functional composition, and the competitive ability of dominant species. Nitrogen increased the CWM of functional traits to improve the competitive ability of dominant species. In contrast, clipping influenced species diversity positively by decreasing CWMheight (P < 0.001), and also negatively by increasing CWMSLA (P < 0.001) and decreasing CV_NNDSLA (P < 0.05). Interacting with N addition, clipping resulted in a neutral effect on species diversity, because clipping could offset the negative effects of nitrogen addition through an opposite effect on CWMheight. This study provides new insights into the mechanisms of diversity maintenance with respect to nitrogen addition and clipping. Thus, clipping is recommended as a useful management strategy to alleviate the species loss caused by nutrients enrichment and maintain the diversity of grassland ecosystems.

Beech and hornbeam dominate oak 20 years after the creation of storm-induced gaps

Oak (Quercus petraea (Matt.) Liebl. and Quercus robur L. grouped), European beech (Fagus sylvatica L.) and hornbeam (Carpinus betulus L.) are three major species of western and central European forests. When conditions are suitable for the three species, silvicultural management often favours oak because of its greater economic interest. Forest managers know that beech and hornbeam are strong competitors for oak during the regeneration phase, but the conditions that influence the relative success of the regeneration of the three species growing in mixture are still poorly characterised. The natural regeneration of the three species 20 years after canopy openings was studied based on 108 study sites established in 2001 in French forests impacted by the windstorms Lothar and Martin in 1999. In spring and summer 2018 and 2019, all saplings over 0.1 m in height were counted, species were identified and diameter at breast height (DBH) was measured for all saplings over 1.30 m. The height of the saplings with the highest and median DBH in each plot was recorded for each species. Mixed models were used to analyse the combined effects of former stand type, distance from the edge of the gap and soil conditions on species presence, sapling abundance, DBH and height. The modelling approach highlighted the preponderant role of the initial seed rain on the presence and sapling density of the three species compared to interspecific competition or distance from the edge. The two latter factors had a secondary effect on sapling DBH and height. Beech and hornbeam saplings were more abundant than oak saplings regardless of soil conditions (on average, 3097, 3063 and 344 saplings ha−1, respectively), suggesting a strong competitive ability of these two species. Oak was present on 22% (43% for hornbeam and 68% for beech) of the studied plots, at a low density but with a height and DBH similar to that of beech or hornbeam. This result highlights the high dissemination capacity of beech and hornbeam, which prevents the establishment of a stand dominated by oak. When seeking to obtain oak-dominated stands in the lowlands of Europe, the abundance of beech and hornbeam can be a limiting factor that could lead to the disappearance of oak from large areas if no silvicultural operations are performed to promote it.

Remora optimization algorithm

In this paper, Remora Optimization Algorithm (ROA) is proposed, which is a new bionics-based, natural-inspired, and meta-heuristic algorithm. The inspiration for ROA is mainly due to the parasitic behavior of remora. Different locations are updated in different hosts: In some large hosts, remora feeds on the host's ectoparasites or wreckage and evades natural enemies, for example in the case of giant whales. In some small hosts, remora follows the host to move to the bait-rich area to prey, taking the fast-moving swordfish as an example. In the case of these two update methods, remora also makes some judges based on experience. If it takes the initiative to prey, it updates the host, makes a global update. If it eat around the host, remora does not change the host, and continues to local update. This algorithm is more inclined to provide a new idea for memetic algorithm, because the host in ROA can be reasonably replaced, such as ships, turtles, etc. The above dynamic mode and behavior are simulated mathematically and the validity of the ROA is tested with 29 benchmark questions and 5 actual engineering questions. Parallel comparisons are made with 10 other natural heuristics. The statistical results and comparisons show that ROA provides a very promising prospect and a strong competitive ability compared to other state-of-the-art heuristic techniques.

Sustainability, Efficiency, and Circularity of Weedy Rice Management Strategies

Weeds have always been a serious problem for farmers and especially nowadays given the current challenges related to food security and agriculture sustainability. During the last three decades, the increasing scarcity of labor, energy, and water has led to a switch of the rice establishment method from traditional hand transplanting to direct seeding. While the latter presents some advantages, it also fosters weeds among which weedy rice is considered the worst because it has a strong competitive ability, and as a congeneric of cultivated rice is very difficult to control. There are currently three main weed management strategies in rice: synthetic herbicides, herbicide-resistant rice varieties, and integrated weed management (IWM). However, all these strategies have low effectiveness and sustainability. Even though IWM is strongly recommended, its adoption remains very low owing to its complexity and the additional cost it induces. The use of crop rotation and cover crops is sustainable and consistent with the circularity principles, but this strategy presents the same drawbacks than those associated with IWM. We stress that other strategies used to control or suppress weedy rice are more efficient, sustainable, and consistent with the bioeconomy principles. They encompass the control of the pathways to weediness by ferality as well as the improvement of rice cultivars’ fitness based on allelopathic effects. Other non-chemical weed management strategies, such as the use of bioherbicides, are promising given the current transition towards bioeconomy and circular economy.

English

Sicyos angulatus has become an important invasive plant exhibiting good ecological adaptability and strong competitive ability. However, studies on this plant at the molecular level are limited by a lack of sequencing data. The present study obtained transcriptome sequences and gene expression profiles using RNA-Seq during S. angulatus seed germination. In total, RNA-Seq generated 491,967,468 reads, which were de novo assembled and 127,874 unigenes with N50 length of 807 bp. About 34.9% of the unigenes (44,660) were annotated against the protein databases, and 35,176 coding sequences were determined. During S. angulatus seed germination, over 127,860 unigenes were expressed and 66,664 unigenes differentially expressed genes (DEGs), among which 8919 DEGs were similar in pairwise comparison. Gene Ontology (GO) analysis of DEGs revealed that genes related to post-embryonic development, meristem development, and photosynthesis were enriched. In addition, the GO term “plant hormone signal transduction pathway” was also enriched in the DEGs. Important changes in genes expression related to auxin and gibberellin signal transduction might possibly be associated with S. angulatus seed germination. The findings of this study provide a foundation for research on S. angulatus that may contribute to prevent further invasion of this plant, consequently protecting the environment. © 2021 Friends Science Publishers