Changes of Tamarix austromongolica forests with embankment dams along the Laizhou bay.

Background: Embankment dams were built south of the Laizhou bay in China for controlling storm surge disasters, but they are not enough to replace coastal forests in protecting the land. This study was designed to evaluate the effects of embankment dams on natural forests dominated by Tamarix austromongolica and test whether the dam-shrub system is a preferable updated defense. Methods: Coastal forests on two typical flats, one before and one behind embankment dams, were investigated using quadrats and lines. Land bareness, vegetation composition and species co-occurrence were assessed; structures of T. austromongolica populations were evaluated; and spatial patterns of the populations were analyzed using Ripley's K and K1,2 functions. Results: In the area before embankment dams, 84.8% of T. austromongolica were juveniles (basal diameter ≤ 3 cm), and 15.2% were adults (basal diameter > 3 cm); behind the dams, 52.9% were juveniles, and 47.1 were adults. In the area before the dams, the land bareness was 13.7%, four species occurred, and they all were ready to co-occur with T. austromongolica; behind the dams, the land bareness was 0%, and 16 species occurred whereas they somewhat resisted co-occurrence with T. austromongolica. In the area before the dams, the T. austromongolica population was aggregated in heterogeneous patches, and the juveniles tended to co-occur with the adults; behind the dams, they were over-dispersed as nearly uniform distributions, while the juveniles could recruit and were primarily independent of the adults. These results indicate that the T. austromongolica species did not suffer from the unnatural dams, but benefited somehow in population expansion and development. Overall, the T. austromongolica species can adapt to artificial embankment dams to create a synthetic defense against storm surges.

The Yellow River is the key corridor for Tamarix austromongolica to disperse from Asia inlands to east seashores.

Plants of the Tamarix L. genus (Tamaricaceae) mainly occur in arid inlands of Asia, but a few species occur in the coastal areas of China, and the Yellow River may account for this. This study was conducted to elucidate whether and how the Yellow River affects the pattern and development of the Tamarix genus, involving two critical species of Tamarix austromongolica Nakai and Tamarix chinensis Lour. With geographical distribution data, relationships of T. austromongolica with the Yellow River and the pertaining watershed were examined using the method of random permutation. The base-diameter structures of T. austromongolica populations were investigated and compared between different riparian lands that suffer discriminative water inundation. The nearest distances from T. austromongolica locations to the Yellow River and the pertaining watershed were significantly lower than the theoretical expectations in the condition of random distribution (p < .05). In many riparian lands along the Yellow River, wild T. austromongolica populations occurred with vigorous juveniles, despite frequent human disturbances. In coastal areas near the present estuary of the river, wild T. austromongolica plants were still found. In T. austromongolica populations near the Yellow River and sea, the rates of juvenile plants were significantly higher than in other populations situated farther from the river or sea. These findings suggest that the Yellow River can facilitate the eastward dispersal of Tamarix plants that reasonably caused the evolution from T. austromongolica to T. chinensis in ancient coasts in the China east.

The association between time-restricted eating and arterial stiffness status in community-dwelling elderly Chinese individuals.

BACKGROUND AND AIMS: Emerging studies indicate that time-restricted eating (TRE) may protect against cardiovascular disease (CVD); however, studies performed in elderly adults are limited. This study aimed to analyze the association of TRE with arterial stiffness (AS) in community-dwelling elderly Chinese individuals. METHODS AND RESULTS: This cross-sectional study recruited 3487 participants aged ≥60 y from Shanghai, China. TRE was determined by calculating the end time of the last meal minus the start time of the first meal of the average day. Participants were then categorized into those with a time-restricted window lasting ≤11 h (TRE) and >11 h (non-TRE). The mean age of the sample was 71.78 ± 5.75 y, and 41.2 % were men. Having a TRE pattern was 72.2 %. In the logistic analysis, TRE was associated with borderline arterial stiffness (OR = 1.419; 95 % CI = 1.077-1.869) and elevated arterial stiffness (OR = 1.699; 95 % CI = 1.276-2.263). In a subgroup analysis, the significance remained in the group at risk of malnutrition (with borderline arterial stiffness: OR = 2.270; 95 % CI = 1.229-4.190; with elevated arterial stiffness: OR = 2.459; 95 % CI = 1.287-4.700), while in well-nourished participants, the association only remained with elevated arterial stiffness (OR = 1.530; 95 % CI = 1.107-2.115) and not with borderline arterial stiffness. CONCLUSIONS: TRE is a risk factor for both borderline and elevated arterial stiffness in community-dwelling Chinese individuals and varies by nutritional status. (Protocol code 2019-WJWXM-04-310108196508064467.).

Community plant height modulated by aridity promotes spatial vegetation patterns in Alxa plateau in Northwest China.

Spatial vegetation patterns are associated with ecosystem stability and multifunctionality in drylands. Changes in patch size distributions (PSDs) are generally driven by both environmental and biological factors. However, the relationships between these factors in driving PSDs are not fully understood. We investigated 80 vegetation plots along an aridity gradient in the Alxa plateau, Northwest China. The sizes of vegetation patches were obtained from aerial images, and the heights of patch-forming species were measured in the field. Soil samples were collected on the bare ground between patches for determination of physiochemical properties. Point pattern analysis was used to infer plant-plant interactions. A model selection procedure was employed to select the best predictors for the shape of PSDs and biological factors (vegetation total cover, community plant height, and plant-plant interactions). We then used structural equation modeling to evaluate the direct and indirect effects of environmental and biological factors on the shape of PSDs. In our study area, two types of PSDs coexisted, namely those that best fit to power law distributions and those that best fit to lognormal distributions. Aridity was the main environmental factor, while community mean height and competition between plants were the main biological factors for the shape of PSDs. As aridity and community mean height increased, power law-like PSDs were exhibited, whereas competition led to deviations of PSDs from power laws. Aridity affected the shape of PSDs indirectly through changes in community mean height. Community mean height was correlated with competition, thereby indirectly affecting the shape of PSDs. Our results suggest the use of community functional traits as a link between the environment and plant-plant interactions, which may improve the understanding of the underlying mechanisms of PSD dynamics.

Lighting Nanoscale Insulators by Steric Restriction-Induced Emissions.

Luminescence detection is a sensitive approach for high-resolution visualization of nano-/macrosized objects, but it is challenging to light invisible insulators owing to their inert surfaces. Herein, we discovered a steric restriction-induced emission (SRIE) effect on nanoscale insulators to light them by fluorogenic probes. The SRIE effect enabled us to specifically differentiate a representative nanoscale insulator, boron nitride (BN) nanosheets, from 18 tested nanomaterials with 420-fold increments of photoluminescence intensity and displayed 3 orders of magnitude linearity for quantitative analysis as well as single-particle level detection. Molecular dynamics simulations indicated that the hydrophobic and electron-resistant surfaces of BN nanosheets restricted intramolecular motions of fluorogenic molecules for blockage of the nonradiative path of excited electrons and activation of the radiative electron transition. Moreover, the lighted BN nanosheets could be successfully visualized in complex cellular and tissue biocontexts. Overall, the SRIE effect will inspire more analytical techniques for inert materials.

ACE2 gene combined with exercise training attenuates central AngII/AT1 axis function and oxidative stress in a prehypertensive rat model.

Angiotensin-converting enzyme 2 (ACE2) or exercise training (ExT) is beneficial to hypertension, but their combined effects remain unknown. In this study, lentivirus containing enhanced green fluorescent protein (eGFP) and ACE2 were microinjected into the paraventricular nucleus (PVN) of young male spontaneous hypertensive rats (SHRs), and SHRs were assigned into five groups: sedentary (SHR), SHR-ExT, SHR-eGFP, ACE2 gene (SHR-ACE2), and ACE2 gene combined with ExT (SHR-ACE2-ExT). Wistar-Kyoto (WKY) rats were used as a control. ACE2 gene or ExT significantly delayed the elevation of blood pressure, and the combined effect prevented the development and progression of prehypertension. Either ACE2 overexpression or ExT improved arterial baroreflex sensitivity (BRS), whereas the combined effect normalized BRS in SHR. Compared with SHR, SHR-ACE2 and SHR-ExT displayed a significantly higher level of ACE2 protein but had lower plasma norepinephrine (NE) and angiotensin II (AngII) as well as angiotensin II type 1 receptor (AT1) protein expression in the PVN. SHR-ACE2-ExT showed the largest decrease in AngII and AT1 protein expression. Reactive oxygen species (ROS) level and NADPH oxidase (NOX2 and NOX4) protein expression in PVN were also decreased in SHR-ACE2-ExT group than in SHR-ACE2 and SHR-ExT groups. It was concluded that the combined effect has effectively prevented prehypertension progression and baroreflex dysfunction in SHR, which is associated with the reduction in AngII/AT1 axis function and oxidative stress in the PVN.NEW & NOTEWORTHY Angiotensin-converting enzyme 2 (ACE2) gene in combination with exercise training (ExT) delayed the progression of hypertension via normalizing the blunted baroreflex sensitivity (BRS) and inhibiting sympathetic nerve activity (SNA). Its underlying mechanism may be related to the inhibition of AngII/AT1 axis function and central oxidative stress in the paraventricular nucleus (PVN) of prehypertensive rats.

Antibiotic-Like Activity of Atomic Layer Boron Nitride for Combating Resistant Bacteria.

The global rise of antimicrobial resistance (AMR) that increasingly invalidates conventional antibiotics has become a huge threat to human health. Although nanosized antibacterial agents have been extensively explored, they cannot sufficiently discriminate between microbes and mammals, which necessitates the exploration of other antibiotic-like candidates for clinical uses. Herein, two-dimensional boron nitride (BN) nanosheets are reported to exhibit antibiotic-like activity to AMR bacteria. Interestingly, BN nanosheets had AMR-independent antibacterial activity without triggering secondary resistance in long-term use and displayed excellent biocompatibility in mammals. They could target key surface proteins (e.g., FtsP, EnvC, TolB) in cell division, resulting in impairment of Z-ring constriction for inhibition of bacteria growth. Notably, BN nanosheets had potent antibacterial effects in a lung infection model by P. aeruginosa (AMR), displaying a 2-fold increment of survival rate. Overall, these results suggested that BN nanosheets could be a promising nano-antibiotic to combat resistant bacteria and prevent AMR evolution.

Effects of Exercise Training on PPARß/δ Expression in Skeletal Muscle of Rats with Spontaneous Hypertension.

PURPOSE: This study aimed to identify the relationship and mechanism between skeletal muscle peroxisome proliferator-activated receptor ß/δ (PPARß/δ) and spontaneous hypertension. METHODS: Rats were divided into four groups ( n = 10): spontaneous hypertensive rats exercise group (SHR-E), spontaneous hypertensive rats sedentary group (SHR-S), Wistar-Kyoto control rats exercise group (WKY-E), and Wistar-Kyoto control rats sedentary group (WKY-S). Although the sedentary groups were placed on the treadmill without moving during the training sessions, the exercise groups were forced to run on a treadmill for 8 wk, 1 h·d -1 , 5 d·wk -1 . After training, the density and area of gastrocnemius microvessels were observed. PPARß/δ, vascular endothelial growth factor A (VEGFA), superoxide dismutase 2 (SOD-2), and nitric oxide synthase in gastrocnemius were measured by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot. RESULTS: Except the sixth week of age, the systolic blood pressure of SHR-S was significantly higher than that of WKY-S at all time periods. Exercise significantly reduced systolic blood pressure in SHR rats. Compared with the SHR-S group, the WKY-S group had significantly higher PPARß/δ protein level and density of skeletal muscle microvessels. Eight weeks of exercise increased the PPARß/δ, SOD-2, VEGFA, and microvessel density and area in the skeletal muscle of SHR. CONCLUSIONS: Exercise training promoted PPARß/δ mRNA and protein-level expression of PPARß/δ, SOD-2 and VEGFA in skeletal muscle, thus increasing the density and area of skeletal muscle blood vessels. These regulations contribute to the reduction of peripheral vascular resistance. This may be a potential mechanism of exercise to reduce blood pressure.

Biotransformation of rare earth oxide nanoparticles eliciting microbiota imbalance.

BACKGROUND: Disruption of microbiota balance may result in severe diseases in animals and phytotoxicity in plants. While substantial concerns have been raised on engineered nanomaterial (ENM) induced hazard effects (e.g., lung inflammation), exploration of the impacts of ENMs on microbiota balance holds great implications. RESULTS: This study found that rare earth oxide nanoparticles (REOs) among 19 ENMs showed severe toxicity in Gram-negative (G-) bacteria, but negligible effects in Gram-positive (G+) bacteria. This distinct cytotoxicity was disclosed to associate with the different molecular initiating events of REOs in G- and G+ strains. La2O3 as a representative REOs was demonstrated to transform into LaPO4 on G- cell membranes and induce 8.3% dephosphorylation of phospholipids. Molecular dynamics simulations revealed the dephosphorylation induced more than 2-fold increments of phospholipid diffusion constant and an unordered configuration in membranes, eliciting the increments of membrane fluidity and permeability. Notably, the ratios of G-/G+ reduced from 1.56 to 1.10 in bronchoalveolar lavage fluid from the mice with La2O3 exposure. Finally, we demonstrated that both IL-6 and neutrophil cells showed strong correlations with G-/G+ ratios, evidenced by their correlation coefficients with 0.83 and 0.92, respectively. CONCLUSIONS: This study deciphered the distinct toxic mechanisms of La2O3 as a representative REO in G- and G+ bacteria and disclosed that La2O3-induced membrane damages of G- cells cumulated into pulmonary microbiota imbalance exhibiting synergistic pulmonary toxicity. Overall, these findings offered new insights to understand the hazard effects induced by REOs.

Engineering Fe-N Doped Graphene to Mimic Biological Functions of NADPH Oxidase in Cells.

NADPH oxidase (NOX) as a transmembrane enzyme complex controls the generation of superoxide that plays important roles in immune signaling pathway. NOX inactivation may elicit immunodeficiency and cause chronic granulomatous disease (CGD). Biocompatible synthetic materials with NOX-like activities would therefore be interesting as curative and/or preventive approaches in case of NOX deficiency. Herein, we synthesized a Fe-N doped graphene (FeNGR) nanomaterial that could mimic the activity of NOX by efficiently catalyzing the conversion of NADPH into NADP+ and triggering the generation of oxygen radicals. The resulting FeNGR nanozyme had similar cellular distribution to NOX and is able to mimic the enzyme function in NOX-deficient cells by catalyzing the generation of superoxide and retrieving the immune activity, evidenced by TNF-α, IL-1ß, and IL-6 production in response to Alum exposure. Overall, our study discovered a synthetic material (FeNGR) to mimic NOX and demonstrated its biological function in immune activation of NOX-deficient cells.

Engineering the Protein Corona Structure on Gold Nanoclusters Enables Red-Shifted Emissions in the Second Near-infrared Window for Gastrointestinal Imaging.

The application of NIR-II emitters for gastrointestinal (GI) tract imaging remains challenging due to fluorescence quenching in the digestive microenvironment. Herein, we report that red-shifting of the fluorescence emission of Au nanoclusters (AuNCs) into NIR-II region with improved quantum yields (QY) could be achieved by engineering a protein corona structure consisting of a ribonuclease-A (RNase-A) on the particle surfaces. RNase-A-encapsulated AuNCs (RNase-A@AuNCs) displayed emissions at 1050 nm with a 1.9 % QY. Compared to rare earth and silver-based NIR-II emitters, RNase-A@AuNCs had excellent biocompatibility, showing >50-fold higher sensitivity in GI tract, and migrated homogenously during gastrointestinal peristalsis to allow visualization of the detailed structures of the GI tract. RNase-A@AuNCs could successfully examine intestinal tumor mice from healthy mice, indicating a potential utility for early diagnosis of intestinal tumors.

Vacancies on 2D transition metal dichalcogenides elicit ferroptotic cell death.

Sustainable developments of nanotechnology necessitate the exploration of structure-activity relationships (SARs) at nano-bio interfaces. While ferroptosis may contribute in the developments of some severe diseases (e.g., Parkinson's disease, stroke and tumors), the cellular pathways and nano-SARs are rarely explored in diseases elicited by nano-sized ferroptosis inducers. Here we find that WS2 and MoS2 nanosheets induce an iron-dependent cell death, ferroptosis in epithelial (BEAS-2B) and macrophage (THP-1) cells, evidenced by the suppression of glutathione peroxidase 4 (GPX4), oxygen radical generation and lipid peroxidation. Notably, nano-SAR analysis of 20 transition metal dichalcogenides (TMDs) disclosures the decisive role of surface vacancy in ferroptosis. We therefore develop methanol and sulfide passivation as safe design approaches for TMD nanosheets. These findings are validated in animal lungs by oropharyngeal aspiration of TMD nanosheets. Overall, our study highlights the key cellular events as well as nano-SARs in TMD-induced ferroptosis, which may facilitate the safe design of nanoproducts.

The mechanism of soil nitrogen transformation under different biocrusts to warming and reduced precipitation: From microbial functional genes to enzyme activity.

Soil nitrogen (N) mineralization is a microbially-mediated biogeochemical process that is strongly influenced by changing climates. However, little information is available on the mechanisms behind the response of N mineralization to prolonged warming coupled with drought in soils covered by biocrusts. We used open top chambers to investigate the rate of soil N transformation (ammonification, nitrification and mineralization), enzyme activity and gene abundance in response to warming coupled with reduced precipitation over three years (2016-2018). Warming and drought significantly reduced the N transformation rate, extracellular enzyme activity, and gene abundance in moss-covered soil. For cyanobacteria-covered soil, however, it inhibited enzyme activity and increased the abundance of the nitrification-related genes and therefore nitrification rate. Our treatments had no obvious effects on N transformation and enzyme activity, but reduced gene abundance in bare soil. Biocrusts may facilitate N transformation while the degradation of moss crust caused by climate warming will dampen any regulating effect of biocrusts on the belowground microbial community. Furthermore, belowground microbial communities can mediate N transformation under ongoing warming and reduced precipitation by suppressing ammonification- and nitrification-related gene families, and by stimulating nitrification-related gene families involved in cyanobacteria-covered soil. This study provides a basis for identifying the functional genes involved in key processes in the N cycle in temperate desert ecosystems, and our results further highlight the importance of different biocrusts organisms in the N cycle in temperate deserts as Earth becomes hotter and drier.

Two-Dimensional Tin Selenide (SnSe) Nanosheets Capable of Mimicking Key Dehydrogenases in Cellular Metabolism.

While dehydrogenases play crucial roles in tricarboxylic acid (TCA) cycle of cell metabolism, which are extensively explored for biomedical and chemical engineering uses, it is a big challenge to overcome the shortcomings (low stability and high costs) of recombinant dehydrogenases. Herein, it is shown that two-dimensional (2D) SnSe is capable of mimicking native dehydrogenases to efficiently catalyze hydrogen transfer from 1-(R)-2-(R')-ethanol groups. In contrary to susceptible native dehydrogenases, lactic dehydrogenase (LDH) for instance, SnSe is extremely tolerant to reaction condition changes (pH, temperature, and organic solvents) and displays extraordinary reusable capability. Structure-activity analysis indicates that the single-atom structure, Sn vacancy, and hydrogen binding affinity of SnSe may be responsible for their catalytic activity. Overall, this is the first report of a 2D SnSe nanozyme to mimic key dehydrogenases in cell metabolism.

Engineered Graphene Oxide Nanocomposite Capable of Preventing the Evolution of Antimicrobial Resistance.

Antimicrobial resistance (AMR) is spreading worldwide and keeps evolving to adapt to antibiotics, causing increasing threats in clinics, which necessitates the exploration of antimicrobial agents for not only killing of resistant cells but also prevention of AMR progression. However, so far, there has been no effective approach. Herein, we designed lanthanum hydroxide and graphene oxide nanocomposites (La@GO) to confer a synergistic bactericidal effect in all tested resistant strains. More importantly, long-term exposure of E. coli (AMR) to subminimum inhibitory concentrations of La@GO does not trigger detectable secondary resistance, while conventional antibiotics and silver nanoparticles lead to a 16- to 64-fold increase in tolerance. The inability of E. coli to evolve resistance to La@GO is likely due to a distinctive extracellular multitarget invasion killing mechanism involving lipid dephosphorylation, lipid peroxidation, and peptidoglycan disruption. Overall, our results highlight La@GO nanocomposites as a promising solution to combating resistant bacteria without inducing the evolution of AMR.

Alteration in isotopic composition of gross rainfall as it is being partitioned into throughfall and stemflow by xerophytic shrub canopies within water-limited arid desert ecosystems.

Isotopic composition of gross rainfall has been extensively used as a conservative tracer to track water movement and other hydrological processes in vegetated ecosystems. Recent studies from forest ecosystems, however, demonstrated that vegetation canopies can alter the isotopic composition of rainwater during rainfall partitioning into throughfall and stemflow, likely leading to errors and biases in aforementioned studies. No known studies, to date, had investigated this topic in shrub-dominated arid and semi-arid ecosystems where water is typically the driving factor in ecological, hydrological and biogeochemical processes. In this study, event-based gross rainfall, the throughfall and stemflow induced by shrubs of Caragana korshinskii were measured and samples were collected within a water-limited arid desert ecosystem of northern China, and their water stable isotopes (18O and 2H) were also analyzed in the laboratory. We mainly aimed to investigate whether there is an isotopic enrichment or depletion in stemflow and throughfall in comparison to gross rainfall, and to evaluate the possible underlying mechanisms. Our results indicated an enrichment of both isotopes in stemflow, while a general more depletion in throughfall than in gross rainfall, which is presumably affected by a combinative effects of canopy evaporation, isotopic exchange, and selective canopy storage. Deuterium excess of stemflow were found to be significantly higher (P < 0.05) than that of gross rainfall and throughfall. Moreover, we detected the pronounced "amount effect", with a significant (P < 0.05) negative relationship between isotopic composition and the amount of gross rainfall, throughfall, and stemflow, respectively. Our study is expected to contribute to an improved understanding of physical processes and water routing in shrub canopies within vast arid desert ecosystems.

Prehypertension exercise training attenuates hypertension and cardiac hypertrophy accompanied by temporal changes in the levels of angiotensin II and angiotensin (1-7).

Appropriate exercise training (ExT) has been shown to decrease high blood pressure. Accumulating data have indicated the beneficial effects of ExT on prehypertension. This study tested whether prehypertension ExT protects against hypertension and cardiac remodeling in spontaneously hypertensive rats (SHR) and explored the underlying mechanisms by examining the cardiac angiotensin-converting enzyme (ACE) and ACE2 signaling axes. Low-intensity ExT was started in male SHR and control Wistar-Kyoto rats prior to the onset of hypertension and maintained for 8 or 16 weeks. Blood pressure (BP) was measured biweekly by the tail-cuff method. Cardiac function and remodeling were assessed, and changes in the ACE and ACE2 axes were examined after the final ExT session. The results showed that prehypertension ExT slowed the onset and progression of hypertension in SHR. In parallel, hypertrophy in the hearts of hypertensive rats was attenuated, myocardial fibrosis was reduced, and impairment of left ventricular diastolic function was reduced. In the SHR myocardium, the levels of components involved in the ACE-Ang II-AT1 axis were homogeneously and progressively increased, whereas those involved in the ACE2-Ang(1-7)-MAS axis were heterogeneously decreased. Different temporal responses were observed for the key effectors Ang II and Ang(1-7). Myocardial Ang II levels were progressively increased in SHR and were consistently reduced by ExT. By contrast, Ang(1-7) decreased only after 16 weeks of sedentariness, and this decrease was abolished by ExT. In addition, 16 weeks of ExT increased the levels of Ang(1-7) in normotensive control rats. In summary, prehypertension ExT attenuates hypertension and cardiac remodeling. Downregulation of Ang II seems to serve as a protective mechanism during ExT, while upregulation of Ang(1-7) is induced after a relatively long period of ExT.

Meteorological influences on process-based spatial-temporal pattern of throughfall of a xerophytic shrub in arid lands of northern China.

Numerous field experiments had demonstrated great spatial variability and temporal stability of throughfall under tree canopies within forested ecosystems. Nonetheless, no known studies have investigated the intrastorm spatial-temporal variability of throughfall beneath xerophytic shrub canopies within arid desert ecosystems where water is typically the principal limiting factor determining the structure and dynamics of ecosystems. Here we investigated the spatial-temporal pattern of throughfall at intrastorm scale, and systematically examined the effects of meteorological variables on throughfall based on the principal components analysis (PCA) and a multiple regression model. Throughfall was monitored at 10-min intervals by placing tipping-bucket rain gauges at different radial directions beneath 3 shrubs of Caragana korshinskii during the growing season of 2016 within a water-limited arid desert ecosystem of northern China. We found the temporal heterogeneity of rainfall clearly affected the timing of throughfall beneath shrub canopies within discrete rainfall events. Throughfall also differed markedly among different radial directions beneath shrub canopies, which was found to be well associated with wind directions during rainfall events. PCA on meteorological variables indicated that three principal components accounted for 84.2% of the total variance, and we found that the second principal component (loaded strongly on rainfall amount and maximum 10-min rainfall intensity) was the dominant component controlling throughfall and its spatial variability after introducing three principal components into a multiple linear regression model. Our findings highlight the spatial-temporal variability of throughfall at the intrastorm scale, and are expected to be helpful for an improved process-based characterization and modelling of throughfall in vast arid desert ecosystems.

Conservation choice on the rare endangered plants Glehnia littoralis.

The coastal herbs Glehnia littoralis have been domesticated as traditional medicines for many centuries. The domestication may have caused changes or declines of cultivated G. littoralis (CGL) relative to wild G. littoralis (WGL). By comparing fruit properties of CGL and WGL, we tested the hypothesis that domesticated G. littoralis have suffered major declines, and human cultivation cannot be sufficient to conserve this species. We collected fruits of CGL and WGL in the Shandong peninsula, China, and compared their buoyancy in seawater, germination potential after seawater immersion, and thousand-grain weights. Float rates of the WGL and CGL fruits were 95.6 (mean) ± 2.6% (standard deviation) and 30.0 ± 7.1%, respectively. The germination potential of CGL was significantly reduced, although the thousand-grain weights of CGL (21.85 ± 0.17 g) were higher than those of the WGL fruits (14.73 ± 0.21 g). These results suggest that the CGL have experienced significant declines relative to the WGL, presumably due to the loss of seawater inundation, selection and dispersal. These declines disfavour the persistence of CGL, and human domestication and cultivation are believed to be insufficient for conserving G. littoralis. Sand coasts where WGL still persists should be designated timely as nature reserves to conserve this species.