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Rare Earth Elements (REEs) are essential components of modern technology and industry, leading to their increased release into the environment. This review synthesizes current knowledge on the transfer, accumulation, and fractionation of REEs in plants, with a focus on the impacts of REE-triggered stress at different organization levels, and the underlying tolerance mechanisms. We explore the mechanisms governing REE uptake, transport, fractionation and distribution within plants and their potential hormetic and toxic effects under normal and stress conditions. This comprehensive review provides valuable insights into the complex interplay between REE accumulation, stress response, and tolerance mechanisms in plants, fostering a deeper understanding of REE phytotoxicity and the development of sustainable solutions for REE-contaminated ecosystems. [ABSTRACT FROM AUTHOR]

During the aerial spraying of pesticides by plant protection UAVs (unmanned aerial vehicles), droplets are deposited below the aircraft under the influence of rotor airflow. The existence of a downwash airflow can improve the deposition of spray on target crops. However, during operation, variations in flight altitude and the gradual decrease in the payload of pesticide solution in the tank leads to changes in the flow field below the UAV which affects droplets distribution. In order to study this, the downwash airflow speed and droplet distributions below a UAV under different flight altitudes (1.5–3 m) and payloads (0-10 kg) were measured and analysed. The results indicated that the changes in operational parameters normally found during operation can change distribution of downwash airflow in all directions but particularly vertical and this can affect the distribution of spray below the UAV. Through correlation analysis, it was shown that the vertical component of airflow (downwash) had a significant positive correlation with spray deposition and penetration (P < 0.05, B = 0.082, B = 0.029), and a negative correlation with droplet deposition uniformity (coefficient of variation) and drift (P < 0.05, B = −3.818, B = −0.042). Thus, it can be seen that downwash is conducive to spray deposition and penetration, which can improve the droplet distribution uniformity and reduce drift. Thus, the influence mechanism of UAV airflow on droplet distribution was explored and shown to strongly influence have the quality of spraying by plant protection UAVs. • Wireless wind speed sensors used to test the downwash airflow UAV. • Reduction in payload affects the downwash airflow of UAV. • Downwash airflow of UAV in turn affects spray distribution. • Vertical downwash airflow has a significant correlation with droplet distribution. [ABSTRACT FROM AUTHOR]

With the development of the social economy, soil heavy metal pollution has become a common worldwide issue. Therefore, the remediation of soil heavy metal pollution is imminent. This study aimed to investigate the effect of amended compost on reducing heavy metal bioavailability in soil and relieving heavy metals stress on plants under Cu and Zn stress in a pot experiment. To model the restoration of heavy metal-polluted farming soil, conventional compost (CKw), activated carbon compost (ACw), modified biochar compost (BCw) and rhamnolipid compost (RLw) were utilized. The results showed that the application of amended compost could promote the growth and quality of pakchoi and enhance the stress ability of malondialdehyde and antioxidant enzymes to heavy metals. The distribution of Cu and Zn in different subcellular parts of pakchoi was also affected. The application of amended compost significantly reduced the heavy metals content in the shoot of pakchoi, among which the content of Cu and Zn in the shoot of pakchoi in RLw was significantly decreased by 57.29% and 60.07%, respectively. Our results can provide a new understanding for efficient remediation of contaminated farmland soil by multiple heavy metals. [Display omitted] • Adding amended compost can reduce the phytotoxicity of heavy metals on pakchoi. • Sensitivity of soil enzyme activity to heavy metal stress was UA > SU > ALP and CAT. • The order of Zn content in different subcellular parts of pakchoi was FⅠ>FⅣ>FⅡ>FⅢ. • Adding amended compost can reduce the content of edible heavy metals in pakchoi. • Rhamnolipid compost was more suitable to alleviate the stress of metals on pakchoi. [ABSTRACT FROM AUTHOR]

The biogeographical distribution of plants and animals has been extensively studied, however, the biogeographical patterns and the factors that influence bacterial communities in lakes over large scales are yet to be fully understood, even though they play critical roles in biogeochemical cycles. Here, bacterial community compositional data, geographic information, and environmental factors were integrated for 326 Chinese lakes based on previously published studies to determine the underlying factors that shape bacterial diversity among Chinese lakes. The composition of bacterial communities significantly varied among the three primary climatic regions of China (Northern China, NC; Southern China, SC; and the Tibetan Plateau, TIP), and across two different lake habitats (waters and sediments). Sediment bacterial communities exhibited significantly higher alpha-diversity and distance-decay relationships compared to water communities. The results indicate that the "scale-dependent patterns" of controlling factors, primarily influenced by geographical factors, become increasingly pronounced as the spatial scale increases. At a national scale, geographical factors exerted a dominant influence on both the water and sediment communities across all lakes, as geographical barriers restrict the dispersal of individuals. At smaller spatial scales, temperature-driven selection effects played a greater role in shaping water bacterial community variation in the NC, SC, and TIP, while geographical factors had a stronger association with sediment bacterial community variation in the lakes of the three regions. This synthesis offers novel insights into the ecological factors that determine the distribution of bacteria in Chinese lakes. [Display omitted] • Controlling factors of bacterial communities in Chinese lakes were identified. • Bacterial community composition significantly varied across regions and habitats. • Geographical factors drived the variation of water and sediment communities. • Temperature-driven selection effects had significant impacts on water communities. • Distance-decay relationship and α-diversity in sediments were higher than in waters. [ABSTRACT FROM AUTHOR]

Plant litter can greatly alter community compositional dynamics and variability of intraspecific interactions in grasslands, and thus the overall ecosystem structure and functions. However, whether plant activity can be driven by plant litter to modify plant community heterogeneity remains poorly explored. We investigate the responses of plant community heterogeneity to litter addition as well as their associated mechanisms. Here we conducted a three-year field experiment in a Tibetan alpine meadow to explore the effects of multiple plant litter addition (five mass levels and three species) on plant communities. We found that the effect of litter manipulation on plant community heterogeneity was mainly driven by litter mass rather than litter species. Higher litter mass manipulation significantly enhanced plant community heterogeneity, which was mainly determined by the niche breadth of forbs and the distribution patterns of functional composition rather than plant diversity. Our findings provide significant insights for understanding the effects of plant litter on grassland ecosystem dynamics to maintain the structure and function of ecosystems. Furthermore, this study suggests that reasonable management practices (e.g., moderate grazing in non−growing seasons) may be pivotal in achieving sustainability of grassland systems through plant litter dynamics. • Litter mass manipulation enhanced plant community heterogeneity. • Litter effects on distribution patterns contributed to plant community heterogeneity. • Litter effects on plant community heterogeneity were driven by niche breadth variability. • Litter effects on plant community heterogeneity were mainly determined by litter mass. [ABSTRACT FROM AUTHOR]

This paper explores how human disturbance and hydrologic elements affect the spatial distribution pattern of plant diversity in the watershed, taking Shamu watershed in the World Natural Heritage Site as a case study. Spatial analysis of multisource remote sensing and plant diversity plots data were conducted using linear mixed effects models and structural equation models. Results revealed that the distribution of plant diversity in the watershed is mainly affected by human disturbance. However, under similar human disturbance levels, hydrologic elements also affect the plant diversity within the watershed. The topographic undulation and surface runoff significantly promote plant diversity, while the river network density, the watershed shape factor, the river longitudinal gradient do not. The influence of topographic undulation is more obvious than that of runoff on plant diversity, but the effect of topographic undulation and runoff on plant diversity is getting weaker from upstream to downstream within the watershed. In addition, the impact of hydrologic elements on plant diversity is mainly regulated by environmental factors Pre and Tem. The findings clarify how human disturbance and hydrologic elements affect plant diversity distribution within the watershed, optimizing the conservation theory of plant diversity resources and scientifically guiding the region's sustainable development. • Human disturbance contributes most to plant diversity. • Surface runoff and topographic undulation promote plant diversity. • Precipitation and temperature regulate the hydrological impact on plant diversity. • Weaker restrictions of hydrologic elements on plant diversity in downstream. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study provided a robust phylogenetic framework of Polygonatum , based on whole-plastome data. • Polygonatum originated in the HHM region during the early Miocene (c. 20.10 Ma), as well as began to radiate and disperse to other regions since the mid-Miocene. • Decreasing dysploidy accompanied by karyotype change and polyploidization in Polygonatum appears to be associated with its diversification and colonization. Clarifying the process of formation of diversity hotspots and the biogeographic connection between regions is critical in understanding the impact of environmental changes on organismal evolution. Polygonatum (Asparagaceae) is distributed across the Northern Hemisphere. It displays an uneven distribution, with more than 50% of its species occurring in the Himalaya-Hengduan Mountains (HHM). Here, we generated a time-calibrated phylogeny of Polygonatum , based on whole-plastome data, to reconstruct the genus' biogeographical history and morphological/chromosomal evolution. Our phylogenetic analyses strongly support the monophyly of Polygonatum and its division into three sections (i.e., Verticillata , Sibirica , and Polygonatum). Polygonatum originated from the HHM region during the early-Miocene (c. 20.10 Ma), and began to radiate since the mid-Miocene, driven by the uplift of the Qinghai–Tibet Plateau (QTP), increasingly colder/arid climates following the mid-Miocene Climatic Optimum (MMCO), and intensification of the East Asian winter monsoon. Dispersal from the HHM region to other regions was facilitated by the intensification of East Asian summer monsoon in response to global climatic warming during the MMCO. Decreasing dysploidy accompanied by karyotype change and polyploidization in Polygonatum appears to be associated with its diversification and colonization of new ecological niches. Our results highlight the importance of regional tectonic activities and past climatic changes from the Neogene onwards to the spatial–temporal diversification and distribution patterns of plant lineages with a wide distribution in the Northern Hemisphere. They also contribute to the knowledge of the uneven species richness between East Asia and other regions. [ABSTRACT FROM AUTHOR]

Silicon (Si) has the potential to ameliorate the toxic effects of cadmium (Cd) on rice growth and mitigate Cd-uptake by rice under Cd-contaminated soil. However, it is not completely clear whether there are differences in the impacts of different Si management on the chemical behavior of Cd in soil-rice system under Cd-contaminated paddy field. Here, pot trials were conducted to explore the effects of three modes of Si application (T-applying Si at transplanting stage, J-applying Si at jointing stage, TJ-applying Si at transplanting stage and jointing stage with a ratio of 50% to 50%) on the accumulation of Cd in rice grain and the toxic risk of Cd on human health in rice consumption under Cd-polluted soil (4.21 mg·kg−1), and that without Si application was used as control (CK). Results showed that rice growth and Cd-retention in root were enhanced by Si application, and the retention of Cd in TJ root was the highest, reaching 82.36%∼84.06% of total Cd absorbed by rice plant. TJ also elevated soil pH and CEC value significantly during the whole growth period, diminished Cd availability and converted exchangeable-Cd into residual-Cd in soil. Moreover, Si application reduced Cd concentration in iron plaque, while TJ had the lowest concentration of DCB-Cd and the highest molar ratios of Fe/Cd and Mn/Cd. The bioaccessibility of Cd from grains and cooked rice were decreased by Si application. Compared with T and J, the hazard quotient of digestion from cooked white rice of TJ in gastric phase was reduced by 19.61% and 21.94%, respectively. In brief, TJ had more efficiency on reducing the Cd availability in soil during the rice growing period, promoting the retention of Cd in root, decreasing Cd uptake by rice plant and distribution to grains, as well as the bioaccessibility of Cd from cooked rice. These results also provide a novel strategy of Si application to decrease the risk of Cd migration in the soil-rice-humans system and simultaneously promote rice yields. [Display omitted] • The ratio of Cd retained in root treat by TJ was the highest among all treatments. • TJ facilitated the decline of the Cd bioavailability by converting more exchangeable-Cd into residual-Cd in soil. • The iron plaque of TJ with higher molar ratios of Fe/Cd and Mn/Cd obstructed Cd absorption. • The Cd bioaccessibility and toxic risk to human health from cooked rice treated by TJ were decreased obviously. [ABSTRACT FROM AUTHOR]

A field investigation on the content of heavy metals in soils and dominant plants was conducted in three sites (A<0.5 km, B<1.0 km, C<1.5 km) with different distances of mine tailings. The spatial distribution of heavy metals and the accumulation in plants were compared, and the candidate species for ecosystem restoration were selected. The results indicated that the soil was polluted by chromium (Cr), Cadmium (Cd), copper (Cu), nickel (Ni) in varying degrees, which is 2.07, 2.60, 1.79, and 4.49 times higher than the Class-Ⅱ standard in China. The concentrate of Ni, Cd, and Zinc (Zn) increased, while Cr, Lead (Pb), and Cu decreased with the distance from the mine tailings. 73 species (34 families) were found and mainly herbaceous plants. The concentrate of Cd, Cu, Cr, and Ni in 29 dominant plants were measured and 66.67%, 21.43%, 100%, 47.62% plants exceeded the normal concentration range. Based on the comparative analysis of heavy metal content, bioconcentration factor, and translocation factor in plants, Polygonum capitatum has good phytoextraction ability, Boehmeria nivea , Chrysanthemum indicum , Miscanthus floridulus , Conyza canadensis , Rubus setchuenensis , Senecio scandens, and Arthraxon hispidus showed remarkable phytostabilization abilities of Cr, Cd, Ni, and Cu, which can be used as potential phytoremediation candidate. • The area is contaminated with Cr, Cd, Ni and Cu to varying degrees. • The migration and accumulation of heavy metals, soil nutrient content and the diversity of vegetation were related to the distance from the mining tailings. • We screened eight plants with good phytoextraction/phytostabilization capabilities for Cr, Cd, Ni and Cu. [ABSTRACT FROM AUTHOR]