Drought intensity and duration effects on morphological root traits vary across trait type and plant functional groups: a meta-analysis.

The increasing severity and frequency of drought pose serious threats to plant species worldwide. Yet, we lack a general understanding of how various intensities of droughts affect plant traits, in particular root traits. Here, using a meta-analysis of drought experiments (997 effect sizes from 76 papers), we investigate the effects of various intensities of droughts on some of the key morphological root traits. Our results show that root length, root mean diameter, and root area decline when drought is of severe or extreme intensity, whereas severe drought increases root tissue density. These patterns are most pronounced in trees compared to other plant functional groups. Moreover, the long duration of severe drought decreases root length in grasses and root mean diameter in legumes. The decline in root length and root diameter due to severe drought in trees was independent of drought duration. Our results suggest that morphological root traits respond strongly to increasing intensity of drought, which further depends on drought duration and may vary among plant functional groups. Our meta-analysis highlights the need for future studies to consider the interactive effects of drought intensity and drought duration for a better understanding of variable plant responses to drought.

Ru(II)-Catalyzed C-H alkylation of N-Benzyltriflamide with Maleimides: Synthesis of o-Succinimide Substituted Benzaldehydes.

A ruthenium-catalyzed N-benzyltriflamide assisted C-H alkylation with maleimide followed by hydrolysis of in situ generated imine has been developed for the first time. This synthetic method results in the efficient synthesis of o-succinimide derivatives of benzaldehydes. This reaction involves less expensive and mild reaction conditions and shows excellent site selectivity and good functional group compatibility.

Glucoconjugated monoterpene indole alkaloids with xanthine oxidase inhibitory activity from Ophiorrhiza japonica.

Continued interest in the bioactive alkaloids led to the isolation of five undescribed alkaloids (1-5), ophiorglucidines A-E, and seven known analogues (6-12) from the water-soluble fraction of Ophiorrhiza japonica. The structures were elucidated based on spectroscopic data and quantum calculations as well as X-ray crystallographic analysis. The structure of 1 was characterized as a hexacyclic skeleton including a double bridge linking the indole and the monoterpene moieties, which is the first report of a single crystal with this type of structure. Moreover, the inhibitory effect of zwitterionic indole alkaloid glycosides on xanthine oxidase was found for the first time. The alkaloids 2 and 3, both of which have a pentacyclic zwitterionic system, were more active than the reference inhibitor, allopurinol (IC50 = 11.1 µM) with IC50 values of 1.0 µM, and 2.5 µM, respectively. Structure-activity relationships analyses confirmed that the carbonyl group at C-14 was a key functional group responsible for the inhibitory effects of these alkaloids.

Aerobic Oxidation of PMB Ethers to Carboxylic Acids.

The first aerobic protocol of direct transformation of p-methoxybenzyl (PMB) ethers to carboxylic acids efficiently with Fe(NO3)3•9H2O and TEMPO as catalysts at room temperature has been developed. The reaction accommodates C-Br bond, terminal/non-terminal C-C triple bond, amide, cyano, nitro, ester, and trifluoromethyl groups, etc. Even highly selective oxidative deprotection of different benzylic PMB ethers has been realized. The reaction has been successfully applied to the total synthesis of natural product, (R)-6-hydroxy-7,9-octadecadiynoic acid, demonstrating the practicality of the method. Based on experimental studies, a possible mechanism involving oxygen-stabilized benzylic cation has been proposed.

Evaluation of functional group compatibility and development of reaction-accelerating additives in ammonium salt-accelerated hydrazinolysis of amides.

Functional group compatibility in an amide bond cleavage reaction with hydrazine was evaluated for 26 functional groups in the functional group evaluation (FGE) kit. Accurate and rapid evaluation of the compatibility of functional groups, such as nitrogen-containing heterocycles important in drug discovery research, will enhance the application of this reaction in drug discovery research. These data will be used for predictive studies of organic synthesis methods based on machine learning. In addition, these studies led to discoveries such as the unexpected positive additive effects of carboxylic acids, indicating that the FGE kit can propel serendipitous discoveries.

Aridity-dependent shifts in biodiversity-stability relationships but not in underlying mechanisms.

Climate change will affect the way biodiversity influences the stability of plant communities. Although biodiversity, associated species asynchrony, and species stability could enhance community stability, the understanding of potential nonlinear shifts in the biodiversity-stability relationship across a wide range of aridity (measured as the aridity index, the precipitation/potential evapotranspiration ratio) gradients and the underlying mechanisms remain limited. Using an 8-year dataset from 687 sites in Mongolia, which included 5496 records of vegetation and productivity, we found that the temporal stability of plant communities decreased more rapidly in more arid areas than in less arid areas. The result suggests that future aridification across terrestrial ecosystems may adversely affect community stability. Additionally, we identified nonlinear shifts in the effects of species richness and species synchrony on temporal community stability along the aridity gradient. Species synchrony was a primary driver of community stability, which was consistently negatively affected by species richness while being positively affected by the synchrony between C3 and C4 species across the aridity gradient. These results highlight the crucial role of C4 species in stabilizing communities through differential responses to interannual climate variations between C3 and C4 species. Notably, species richness and the synchrony between C3 and C4 species independently regulated species synchrony, ultimately affecting community stability. We propose that maintaining plant communities with a high diversity of C3 and C4 species will be key to enhancing community stability across Mongolian grasslands. Moreover, species synchrony, species stability, species richness and the synchrony between C3 and C4 species across the aridity gradient consistently mediated the impacts of aridity on community stability. Hence, strategies aimed at promoting the maintenance of biological diversity and composition will help ecosystems adapt to climate change or mitigate its adverse effects on ecosystem stability.

Reactive oxygen species play key roles in the nitrite formation by the inorganic nitrate photolysis in the presence of urban water-soluble organic carbon.

Inorganic nitrates were considered to be a potential source of atmospheric NO2-/HONO during the daytime. To better evaluate the contribution of nitrate photochemistry on NO2-/HONO formation, the photolysis of nitrates in the real atmospheric environment needs to be further explored. Here, the NO2- generation by the photolysis of inorganic nitrates in the presence of total water-soluble organic carbon (WSOC) was quantified. The physicochemical properties of WSOC were measured to understand the underlying mechanism for the photolysis of inorganic nitrates with WSOC. WSOC enhanced or suppressed the photochemical conversion of nitrates to NO2-, with the quantum yield of NO2- (ΦNO2-) varying from (0.07 ± 0.02)% to (3.11 ± 0.04)% that depended on the light absorption properties of WSOC. Reactive oxygen species (ROS) generated from WSOC, including O2-/HO2 and OH, played a dual role in the NO2- formation. Light-absorbing substances in WSOC, such as N-containing and carbonyl aromatics, produced O2-/HO2 that enhanced the secondary conversion of NO2 to NO2-. On the other hand, OH deriving from the WSOC photochemistry inhibited the nitrate photodegradation and the NO2- formation. HONO source strength by the aqueous photolysis of nitrates with WSOC was estimated to be lower than 100 ppt h-1, which may partly contribute to the atmospheric HONO source in some cases.

Responses of Protozoan Communities to Multiple Environmental Stresses (Warming, Eutrophication, and Pesticide Pollution).

To explore the impacts of multiple environmental stressors on animal communities in aquatic ecosystems, we selected protozoa-a highly sensitive group of organisms-to assess the effect of environmental change. To conduct this simulation we conducted a three-factor, outdoor, mesocosm experiment from March to November 2021. Changes in the community structure and functional group composition of protozoan communities under the separate and combined effects of these three environmental stressors were investigated by warming and the addition of nitrogen, phosphorus, and pesticides. The results were as follows: (1) Both eutrophication and pesticides had a considerable promotional effect on the abundance and biomass of protozoa; the effect of warming was not considerable. When warming was combined with eutrophication and pesticides, there was a synergistic effect and antagonistic effect, respectively. (2) Eutrophication promoted α diversity of protozoa and affected their species richness and dominant species composition; the combination of warming and pesticides remarkably reduced the α diversity of protozoa. (3) Warming, eutrophication, and pesticides were important factors affecting the functional groups of protozoa. Interaction among different environmental factors could complicate changes in the aquatic ecological environment and its protozoan communities. Indeed, in the context of climate change, it might be more difficult to predict future trends in the protozoan community. Therefore, our results provide a scientific basis for the protection and restoration of shallow lake ecosystems; they also offer valuable insights in predicting changes in shallow lakes.

The ecology of the sewer systems: Microbial composition, function, assembly, and network in different spatial locations.

Microbial induced concrete corrosion (MICC) is the primary deterioration affecting global sewers. Disentangling ecological mechanisms in the sewer system is meaningful for implementing policies to protect sewer pipes using trenchless technology. It is necessary to understand microbial compositions, interaction networks, functions, alongside assembly processes in sewer microbial communities. In this study, sewer wastewater samples and microbial samples from the upper part (UP), middle part (MP) and bottom part (BP) of different pipes were collected for 16S rRNA gene amplicon analysis. It was found that BP harbored distinct microbial communities and the largest proportion of unique species (1141) compared to UP and MP. The community in BP tended to be more clustered. Furthermore, significant differences in microbial functions existed in different spatial locations, including the carbon cycle, nitrogen cycle and sulfur cycle. Active microbial sulfur cycling indicated the corrosion risk of MICC. Among the environmental factors, the oxidation‒reduction potential drove changes in BP, while sulfate managed changes in UP and BP. Stochasticity dominated community assembly in the sewer system. Additionally, the sewer microbial community exhibited numerous positive links. BP possessed a more complex, modular network with higher modularity. These deep insights into microbial ecology in the sewer system may guide engineering safety and disaster prevention in sewer infrastructure.

Electric Double Layer Regulator Design through a Functional Group Assembly Strategy towards Long-Lasting Zinc Metal Batteries.

Regulating the electric double layer (EDL) structure of the zinc metal anode by using electrolyte additives is an efficient way to suppress interface side reactions and facilitate uniform zinc deposition. Nevertheless, there are no reports investigating the proactive design of EDL-regulating additives before the start of experiments. Herein, a functional group assembly strategy is proposed to design electrolyte additives for modulating the EDL, thereby realizing a long-lasting zinc metal anode. Specifically, by screening ten common functional groups, N, N-dimethyl-1H-imidazole-1-sulfonamide (IS) is designed by assembling an imidazole group, characterized by its high adsorption capability on the zinc anode, and a sulfone group, which exhibits strong binding with Zn2+ ions. Benefiting from the adsorption functionalization of the imidazole group, the IS molecules occupy the position of H2O in the inner Helmholtz layer of the EDL, forming a molecular protective layer to inhibit H2O-induced side reactions. Meanwhile, the sulfone group in IS, acting as a binding site to Zn2+, promotes the de-solvation of Zn2+ ions, facilitating compact zinc deposition. Consequently, the utilization of IS significantly extending the cycling stability of Zn||Zn and Zn||NaV3O8 ⋅ 1.5H2O full cell. This study offers an innovative approach to the design of EDL regulators for high-performance zinc metal batteries.

Enhancing catalytic activity of CuCoFe-layered double oxide towards peroxymonosulfate activation by coupling with biochar derived from durian peel for antibiotic degradation: The role of C=O in biochar and underlying mechanism of built-in electric field.

CuCoFe-LDO/BCD was successfully synthesized from CuCoFe-LDH and biochar derived from durian shell (BCD). Ciprofloxacin (CFX) degraded more than 95% mainly by O2•- and 1O2 in CuCoFe-LDO/BCD(2/1)/PMS system within 10 min with a rate constant of 0.255 min-1, which was 14.35 and 2.66 times higher than those in BCD/PMS and CuCoFe-LDO/PMS systems, respectively. The catalytic system exhibited good performance over a wide pH range (3-9) and high degradation efficiency of other antibiotics. Built-in electric field (BIEF) driven by large difference in the work function/Fermi level ratio between CuCoFe-LDO and BCD accelerated continuous electron transfer from CuCoFe-LDO to BCD to result in two different microenvironments with opposite charges at the interface, which enhanced PMS adsorption and activation via different directions. As a non-radical, 1O2 was mainly generated via PMS activation by C=O in BCD. The presence of C=O in BCD resulted in an increase in atomic charge of C in C=O and redistributed the charge density of other C atoms. As a result, strong adsorption of PMS at C atom in C=O and other C with a high positive charge was favorable for 1O2 generation, whereas an enhanced adsorption of PMS at negatively charged C accounted for the generation of •OH and SO4•-. After adsorption, electrons in C of BCD became deficient and were fulfilled with those transferred from CuCoFe-LDO driven by BIEF, which ensured the high catalytic activity of CuCoFe-LDO/BCD. O2•-, on the other hand, was generated via several pathways that involved in the transformation of •OH and SO4•- originated from PMS activation by the transition of metal species in CuCoFe-LDO and negatively charged C in BCD. This study proposed a new idea of fabricating a low-cost metal-LDH and biomass-derived catalyst with a strong synergistic effect induced by BIEF for enhancing PMS activation and antibiotic degradation.

Revealing the interaction forms between Hg(II) and group types (-Cl, -CN, -NH2, -OH, -COOH) in functionalized Poly(pyrrole methane)s for efficient mercury removal.

To explore the impact of different functional groups on Hg(II) adsorption, a range of poly(pyrrole methane)s functionalized by -Cl, -CN, -NH2, -OH and -COOH were synthesized and applied to reveal the interaction between different functional groups and mercury ions in water, and the adsorption mechanism was revealed through combined FT-IR, XPS, and DFT calculations. The adsorption performance can be improved to varying degrees by the incorporation of functional groups. Among them, the oxygen-containing functional groups (-OH and -COOH) exhibit stronger affinity for Hg(II) and can increase the adsorption capacity from 180 mg g-1 to more than 1400 mg g-1 at 318 K, with distribution coefficient (Kd) exceeding 105 mL g-1. The variations in the capture and immobilization capabilities of functionalized poly(pyrrole methane)s predominantly stem from the unique interactions between their functional groups and mercury ions. In particular, oxygen-containing -OH and -COOH effectively capture Hg(OH)2 through hydrogen bonding, and further deprotonate to form the -O-Hg-OH and -COO-Hg-OH complexes which are more stable than those obtained from other functionalized groups. Finally, the ecological safety has been fully demonstrated through bactericidal and bacteriostatic experiments to prove the functionalized poly(pyrrole methane)s can be as an environmentally friendly adsorbent for purifying contaminated water.

Why are graminoid species more dominant? Trait-mediated plant-soil feedbacks shape community composition.

Species traits may determine plant interactions along with soil microbiome, further shaping plant-soil feedbacks (PSFs). However, how plant traits modulate PSFs and, consequently, the dominance of plant functional groups remains unclear. We used a combination of field surveys and a two-phase PSF experiment to investigate whether forbs and graminoids differed in PSFs and in their trait-PSF associations. When grown in forb-conditioned soils, forbs experienced stronger negative feedbacks, while graminoids experienced positive feedbacks. Graminoid-conditioned soil resulted in neutral PSFs for both functional types. Forbs with thin roots and small seeds showed more-negative PSFs than those with thick roots and large seeds. Conversely, graminoids with acquisitive root and leaf traits (i.e., thin roots and thin leaves) demonstrated greater positive PSFs than graminoids with thick roots and tough leaves. By distinguishing overall and soil biota-mediated PSFs, we found that the associations between plant traits and PSFs within both functional groups were mainly mediated by soil biota. A simulation model demonstrated that such differences in PSFs could lead to a dominance of graminoids over forbs in natural plant communities, which might explain why graminoids dominate in grasslands. Our study provides new insights into the differentiation and adaptation of plant life-history strategies under selection pressures imposed by soil biota.

Regulating Functional Groups Enhances the Performance of Flexible Microporous MXene/Bacterial Cellulose Electrodes in Supercapacitors.

Ultrathin MXene-based films exhibit superior conductivity and high capacitance, showing promise as electrodes for flexible supercapacitors. This work describes a simple method to enhance the performance of MXene-based supercapacitors by expanding and stabilizing the interlayer space between MXene flakes while controlling the functional groups to improve the conductivity. Ti3C2Tx MXene flakes are treated with bacterial cellulose (BC) and NaOH to form a composite MXene/BC (A-M/BC) electrode with a microporous interlayer and high surface area (62.47 m2 g-1). Annealing the films at low temperature partially carbonizes BC, increasing the overall electrical conductivity of the films. Improvement in conductivity is also attributed to the reduction of -F, -Cl, and -OH functional groups, leaving -Na and -O functional groups on the surface. As a result, the A-M/BC electrode demonstrates a capacitance of 594 F g-1 at a current density of 1 A g-1 in 3 M H2SO4, which represents a ∼2× increase over similarly processed films without BC (309 F g-1) or pure MXene (298 F g-1). The corresponding device has an energy density of 9.63 Wh kg-1 at a power density of 250 W kg-1. BC is inexpensive and enhances the overall performance of MXene-based film electrodes in electronic devices. This method underscores the importance of functional group regulation in enhancing MXene-based materials for energy storage.

Long-term study of phytoplankton dynamics in a supply reservoir reveals signs of trophic state shift linked to changes in hydrodynamics associated with flow management and extreme events.

This study analyses over a decade (2009-2022) of monitoring data to understand the impact of hydrological characteristics on water quality and phytoplankton dynamics in Prospect Reservoir, a critical water supply for Greater Sydney, Australia, known for its excellent water quality. Water quality and phytoplankton dynamics were related to hydrodynamics, linked to flow management and the water quality of inflows. Phytoplankton biovolume increased after a prolonged drawdown and subsequent refill event, mainly driven by dinoflagellates, and corresponded to increases in total phosphorus and water temperature. The hydrological period following the 2019/2020 summer bushfires (post-bushfire) that impacted connected reservoirs, was marked by increased flow activity and nutrient loading, leading to significant shifts in the phytoplankton community. Functional group classification and ordination analysis indicated a transition from taxa typically dominant in oligotrophic conditions to meso­eutrophic. This transition correlated with elevated nutrient levels and chlorophyll-a (Chl-a), and reduced Secchi depth and dissolved oxygen, providing evidence of eutrophication. Q index indicated good water quality post-bushfire, contrasting with a eutrophic status assessment using Chl-a. Our findings highlight the importance of analysing long-term datasets encompassing varied hydroclimatological conditions for a deeper understanding of reservoir behaviour. A comprehensive approach to water quality assessment is recommended, combining functional group classification, Q index and Chl-a measurements for effective reservoir health assessment. This research provides novel insights into the effects of disturbances such as bushfires, on water quality and phytoplankton dynamics in an underrepresented geographic region, offering valuable knowledge for managing water resources amidst growing climate variability.

Systematic Studies of Functional Group Tolerance and Chemoselectivity in Carbene-Mediated Intramolecular Cyclopropanation and Intermolecular C-H Functionalization.

Generating reliable data on functional group compatibility and chemoselectivity is essential for evaluating the practicality of chemical reactions and predicting retrosynthetic routes. In this context, we performed systematic studies using a functional group evaluation kit including 26 kinds of additives to assess the functional group tolerance of carbene-mediated reactions. Our findings revealed that some intermolecular heteroatom-hydrogen insertion reactions proceed faster than intramolecular cyclopropanation reactions. Lewis basic functionalities inhibited rhodium-catalyzed C-H functionalization of indoles. While performing these studies, we observed an unexpected C-H functionalization of a 1-naphthol variant used as an additive.

Fire facilitates ground layer plant diversity in a Miombo ecosystem.

BACKGROUND AND AIMS: Little is known about the response of ground layer plant communities to fire in Miombo ecosystems, which is a global blind spot of ecological understanding. We aimed: (1) to assess the impact of three experimentally imposed fire treatments on ground layer species composition and compare it with patterns observed for trees; and (2) to analyse the effect of fire treatments on species richness to assess how responses differ among plant functional groups. METHODS: At a 60-year-long fire experiment in Zambia, we quantified the richness and diversity of ground layer plants in terms of taxa and functional groups across three experimental fire treatments of late dry-season fire, early dry-season fire and fire exclusion. Data were collected in five repeat surveys from the onset of the wet season to the early dry season. KEY RESULTS: Of the 140 ground layer species recorded across the three treatments, fire-maintained treatments contributed most of the richness and diversity, with the least number of unique species found in the no-fire treatment. The early-fire treatment was more similar in composition to the no-fire treatment than to the late-fire treatment. C4 grass and geoxyle richness were highest in the late-fire treatment, and there were no shared sedge species between the late-fire and other treatments. At a plot level, the average richness in the late-fire treatment was twice that of the fire exclusion treatment. CONCLUSIONS: Heterogeneity in fire seasonality and intensity supports diversity of a unique flora by providing a diversity of local environments. African ecosystems face rapid expansion of land- and fire-management schemes for carbon offsetting and sequestration. We demonstrate that analyses of the impacts of such schemes predicated on the tree flora alone are highly likely to underestimate impacts on biodiversity. A research priority must be a new understanding of the Miombo ground layer flora integrated into policy and land management.

Co-existing inorganic anions influenced the Norrish I and Norrish II type photoaging mechanism of biodegradable microplastics.

The degradation of biodegradable plastics (BPs) in natural environments is constrained, and the mechanisms underlying their photoaging in aquatic settings remain inadequately understood. In view of this, this study systematically investigated the photoaging process of biodegradable Poly (butyleneadipate-co-terephthalate) microplastics (PBAT-MPs), which are more widely used. The investigation was carried out in the presence of common inorganic anions (Br-, Cl- and NO3-). The results of EPR, FTIR and FESEM tests, along with pseudo-first-order kinetics analyses, showed that the presence of NO3- promoted the photoaging of PBAT-MPs, while the presence of Br- and Cl- inhibited the photoaging of PBAT-MPs. In addition, the results of the Two-Dimensional Correlation Spectroscopy (2D-COS) analysis determined the order of the changes in the functional groups, revealing that the Norrish I and Norrish II reaction mechanisms are presented by PBAT-MPs during the aging process, and the process is closely related to the ion concentration and UV irradiation time. This study provides valuable insights for understanding the phototransformation process of BPs in natural aqueous environments.

Investigation on Combustion Characteristics and Molecular Structures of Heiyanquan Mining Area, Xinjiang, China.

In order to comprehend the molecular composition of coal and better understand the process of coal combustion, this study involved the development of a molecular structure model for Heiyanquan coal in Xinjiang, as well as the optimization and annealing dynamics simulation of the model. Thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (HRTEM) were utilized to investigate the spontaneous combustion characteristics of coal at different temperatures (room temperature, 50-500 °C with 50 °C interval). The findings revealed that the coal primarily consists of aromatic carbon, with the aromatic structure mainly comprising naphthalene, anthracene, and phenanthrene, and the aliphatic carbon mainly consisting of CH2 and CH, along with a small quantity of minerals. The empirical molecular formula of Heiyanquan coal was determined to be C175H125O21N3. After the optimization, the total energy of the model was significantly reduced, and the aromatic layers tended to align in a regular parallel manner, with van der Waals energy playing a crucial role in maintaining structural stability. As the temperature increased, the activation energy of the three stages also increased, with the combustion stage exhibiting the highest activation energy. The presence of hydroxyl groups and oxygen-containing functional groups was found to mainly participate in the reaction, while the content of aromatic hydrocarbons remained relatively stable, C=C exhibited a decreasing trend, and C-O displayed an increasing trend. Moreover, it was observed that 1 × 1 and 2 × 2 were the predominant aromatic stripes in the coal samples, accounting for more than 90% of the total stripes.

Functional Group Analysis of α-Pinene Oxidation Products Using Derivatization Reactions and High-Resolution Electrospray Ionization Collision-Induced Dissociation Mass Spectrometry.

Oxidation products of monoterpenes (C10H16) play a significant role as precursors for secondary organic aerosol formation. They contain several structural isomers with multifunctional groups. However, only a few of these isomers have been identified experimentally. We describe a measurement technique for identifying oxygen-containing functional groups (carbonyl, carboxyl, and hydroxyl groups) included in monoterpene oxidation products. This technique involves (i) three derivatization reactions (oximation of carbonyls by O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine, methyl esterification of carboxylic acids by trimethylsilyl diazomethane, and acylation of alcohols by acetic anhydride), (ii) no preseparation high-resolution electrospray ionization mass spectrometry, and (iii) collision-induced dissociation. This technique was applied to functional group analysis of ozonolysis products for α-pinene. Multifunctional groups of known ozonolysis products were accurately identified. Furthermore, we successfully estimated the multifunctional groups of products that have not been previously reported.