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The investigation into trade-offs among plant functional traits sheds light on how plants strategically balance growth and survival when facing environmental stress. This study sought to evaluate whether trade-offs observed at both community and individual species levels could indicate adaptive fitness across an intensity of flooding intensity. The study was conducted at 25 sampling sites spanning approximately 600 km along the riparian zone in the Three Gorges Reservoir area, China. The findings revealed that, along the flooding gradient, the overall riparian community did not exhibit significant trade-offs between leaf and root traits. Examining three broadly distributed dominant species (Cynodon dactylon, Xanthium strumarium, and Abutilon theophrasti), perennial plants showed pronounced trade-offs under low flooding intensity, while annuals exhibited trade-offs under moderate and low flooding intensity. The trade-offs were evident in traits related to nitrogen-carbon resources, such as specific leaf area, root tissue density, and photosynthetic rate. However, under strong flooding intensity, the relationship between leaf and root traits of the species studied was decoupled. Furthermore, the study identified a significant correlation between soil nitrogen and the trade-off traits under moderate and low flooding intensity. Integrating results from the CSR (Competitors, Stress-tolerators, Ruderals) strategy model, species niche breath analysis, and nitrogen-regulated trade-off, the study revealed that, in the face of high flooding intensity, perennial species (C. dactylon) adopts an S-strategy, demonstrating tolerance through a conservative resource allocation that decouples leaf-root coordination. Annual species (X. strumarium and A. theophrasti), on the other hand, exhibit niche specialization along the flooding gradient, employing distinct strategies (R- and C-strategy). As flooding stress diminishes and soil nitrogen level decreases, plant strategies tend to shift towards an R-strategy with a competition for reduced N resources. In conclusion, the study highlighted the pivotal roles of soil nitrogen and flooding intensity acting as the dual determinants of species growth and tolerance. These dynamics of growth-tolerance balance were evident in the diverse trade-offs between leaf and root traits of individual plant species with different life histories, underscoring the array of adaptive strategies employed by riparian plants across the flooding intensity gradient. [ABSTRACT FROM AUTHOR]

By virtue of remarkable tolerance on hypoxia and adaptive specialization in morphology, diverse hexactinellid sponges prospered in an early Cambrian environment characterized by dysoxic bottom waters documented by black shales. New fossils from the black shale of the Niutitang Formation (basal Stage 3 of Cambrian) in Hunan Province of China, reveal for the first time an articulated body of the sponge Hyalosinica archaica Mehl & Reitner in Steiner et al., 1993, which possesses an ovoid main body and an impressive long stalk. The spicular skeleton includes large diactines that are generally organized as fan-shaped clusters, a few small stauractines and hexactines, and twisted bundles of long monaxons that form the stalk/root tuft. This hexactinellid sponge represents the oldest extinct taxon that took advantage of a long stalk to elevate the main body above the sediment surface and thus to adapt to the oxygen-deficient sea-bottom environment. The long root tuft links Hyalosinica to a series of fossil and recent sponge taxa and proves a deep origin of the stalk-bearing morphology, indicating a likely parallel evolution within the Hexactinellida in response to special environmental pressures. Furthermore, the overall skeletal organization indicates that Hyalosinica, as well as related early ‘rossellimorphs’, are basal stem group representatives of Hexactinellida and probably branched before the extinct Reticulosa and before the two extant hexactinellid subclasses. [ABSTRACT FROM AUTHOR]

In arid and semi-arid sand dune ecosystems, belowground bud bank plays an important role in population regeneration and vegetation restoration. However, the responses of belowground bud bank size and composition to sand burial and its induced changes in soil environmental factors have been rarely studied. In arid sand dunes of Northwestern China, we investigated belowground bud bank size and composition of the typical rhizomatous psammophyte Psammochloa villosa as well as three key soil environmental factors (soil moisture, total carbon and total nitrogen) under different depths of sand burial. Total buds and rhizome buds increased significantly with increasing burial depth, whereas tiller buds first increased and then decreased, with a peak value at the depth of 20-30 cm. Soil moisture increased significantly with sand burial depth, and was positively correlated with the number of all buds and rhizome buds. Soil total carbon concentration first increased and then decreased with sand burial depth, and total nitrogen concentration was significantly lower under deep sand burial than those at shallow depths, and only the number of tiller buds was positively correlated with soil total nitrogen concentration. These results indicate that soil moisture rather than soil nutrient might regulate the belowground bud bank of P. villosa, and that clonal psammophytes could regulate their belowground bud bank in response to sand burial and the most important environmental stress (i.e., soil moisture). These responses, as the key adaptive strategy, may ensure clonal plant population regeneration and vegetation restoration in arid sand dunes. [ABSTRACT FROM AUTHOR]

Sustainable development goals (SDGs) emphasize a holistic achievement instead of cherry-picking a few. However, no assessment has quantitatively considered the evenness among all 17 goals. Here, we propose a systematic method, which first integrates both the evenness and the overall status of all goals, to distinguish the ideal development pathways from the uneven ones and then revisit the development trajectory in China from 2000 to 2015. Our results suggest that, despite the remarkable progress, a bottleneck has occurred in China since 2013 due to the stagnant developments in some SDGs. However, many far-reaching policies in China have been targeting these deficiencies since then, providing a perspective on how a country approaches sustainable development by promoting evenness among all SDGs. Our results also indicate that regions with the slowest progress are the developed provinces, owing to the persistent uneven status of all goals. Our study demonstrates the importance of adopting evenness in assessing and guiding sustainable development. [ABSTRACT FROM AUTHOR]

Adjustments to the allocation of aboveground biomass allocation are an important component of the adaptive strategies of plant growth. Plants can modify their biomass allocation patterns to adapt to various environmental conditions. Sandy areas vary widely in topography, generating a diversity of microenvironments. However, knowledge about biomass allocation patterns of shrubs in different microtopographic areas in sandy habitats remains limited. Moreover, most studies have not considered the effect of age on plant biomass allocation responses to habitat differences. In August 2017, we measured the age, height, ground-level diameter, and leaf and stem matter of Salix psammophila, a species that overwhelmingly dominates a wide range of habitats in China. Biomass allocation patterns (leaf vs. stem biomass, biomass vs. diameter) were compared between two sandy vegetation environments in an area of the Mu Us Sandy Land. The results indicated that the rate of biomass accumulation decreased with age and, as shoots aged, they tended to allocate more biomass to stems, which provide support and transport functions, than to leaves (assimilatory organs). Soil moisture was the main environmental factor influencing the allocation strategy of S. psammophila. Favorable moisture habitats increased the overall biomass accumulation rate by promoting the allocation of biomass to leaf tissue. Habitat and age had an interactive effect on biomass accumulation and allocation, and larger plants were more likely to suffer from resource limitation. This study contributes to a better understanding of the life-history strategies of shrubs under frequently changing sandy conditions, which can contribute to efforts in vegetation recovery management. [ABSTRACT FROM AUTHOR]

Urbanization has resulted in obvious changes in plant species diversity. We analyzed the dynamics of ruderal species diversity in Harbin over the past half century using historical data collected in 1955 and data of the present spatial distribution in 2010-2011. The results show that, the number of ruderal species decreased from 611 to 175 with remarkable tendency of decreasing in perennial species and increasing in winter annual species in the past half century, which caused the shift of life form spectrum from perennial mono-dominant type to summer annual and perennial co-dominant type. Meanwhile, the proportion of tropical originated species increased and the proportion of temperate originated species decreased which were considered to relate with the increase of temperature in urban area during the past half century. Moreover, there was a distinct decrease of the proportion of aquatic and hygrophytic ruderal species while an increase of mesic and xeric ruderal species which suggested a drought trend in urban habitats that consistent with the change of land use characterized as decrease of natural water bodies and wetlands and increase of urban land. Comparison of ruderal species along urbanization gradient also got the similar results with the above results from analysis on temporal scales and confirmed the effect of urbanization on decreasing plant richness. Our results suggested that land use change combined with its effect on temperature and disturbance regimes in urban habitats preferred species with short life span, high drought tolerance, fast growth rates and high seed yields. [ABSTRACT FROM AUTHOR]

Abstract: A better understanding of plant water relations is needed for evaluating the suitability of plant species to site-specific reforestation programs in the heterogeneous karst landscapes in southwestern China that are characterized by temporary water deficit. During both wet and dry periods, leaf water potentials of 65 plant species from five different growth forms were studied at three representative sites (forest, shrubland and grassland), to compare their adaptive strategies against water stress and assess their suitability for reforestation programs. Herbs showed the highest predawn and midday water potentials and smallest diurnal ranges of water potential values at all the three sites, indicating that they follow water stress avoidance strategies. During the dry period, evergreen shrubs showed low water potentials, the largest diurnal ranges and highest soluble sugar contents. This indicates that they have a tolerance strategy responding to water stress. Deciduous shrubs and trees still showed relatively large diurnal ranges of water potential values and high soluble sugar contents, and did not shed leaves when experiencing the lowest midday water potentials during the dry period. They shed leaves only later in the dry winter period when even more serious drought was experienced. Their strategies seem to include both tolerance and avoidance mechanisms. Evergreen trees revealed relatively low water potentials with smallest diurnal range water potentials at the shrubland site, especially during the dry period, which indicated their weak ability to tolerate severe water stress. Increasing degradation of the vegetation clearly impacts negatively plant water relations. Using the ranges of leaf water potentials, the relative suitability of the plants for reforestation could be evaluated. [Copyright &y& Elsevier]

• We determine tunnel stability in soil with a soft upper layer and hard lower layer. • The effects of multiple soil layers and different soft soil parameters on an underground tunnel in China are studied. • We present the upper-bound finite element method with a mesh adaptive strategy. • Two main reasons for tunnel instability and large surface settlement are presented. • Two construction proposals are presented to ensure normal working conditions and safety of engineering. This paper presents a limit analysis of a tunnel in non-homogeneous soil using the upper-bound limit analysis in combination with finite element technology and a mesh adaptive strategy by investigating the critical loads and failure mechanisms of a tunnel cross-section and tunnel face. A case study of an underground tunnel in China is conducted, with a focus on the effects of multiple soil layers and different soft soil parameters. This work demonstrates that the variation in the soil layering plays an important role in the initiation of tunnel collapse, possibly shifting the failure region and even changing the failure mechanism. When the soil changes from a strongly weathered conglomerate to a soft soil, not increasing the low tunnel pressure quickly enough and using the wrong excavation mode are the two main reasons for tunnel instability and large surface settlement. [ABSTRACT FROM AUTHOR]

Background: Non-optimal weather conditions and air pollution pose a significant threat to children's health. However, the relative impact of different environmental exposures on childhood allergic diseases remains unclear., Objectives: This study aimed to quantify the relative impact of meteorological factors and air pollutants on childhood allergic diseases in Shanghai, China., Methods: Data on clinical visits due to childhood asthma, allergic rhinitis (AR) and atopic dermatitis (AD) from 2007 to 2017 in Shanghai were collected from Shanghai Children's Medical Center and Xinhua Hospital. The meteorological data (i.e. daily mean temperature, temperature difference, air pressure, air pressure difference, precipitation, relative humidity, sunshine and wind speed) for the same period were obtained from the Shanghai Meteorological Center. Air pollution data (PM 10 , PM 2.5 , NO 2 , SO 2 and O 3 ) were provided by the Shanghai Environmental Protection Agency. Quasi-Poisson regression with distributed lag non-linear models and Poisson regression combined with generalized linear models were used to assess the relative impact of meteorological factors and air pollutants on childhood allergic diseases., Results: There were a total of 2,410,392 cases of childhood allergic diseases, including 975,771 asthma, 646,975 AR and 787,646 AD. Most of environmental factors were significantly associated with childhood allergic diseases. Daily mean temperature (standard β: -0.076 (95% confidence interval (CI): -0.086, -0.067)) and air pressure (standard β: 0.075 (95% CI: 0.068, 0.082)) seemed to play more important roles than other environmental factors in the occurrence of these allergic diseases. The numbers of these allergic diseases attributable to an interquartile range (IQR) change in meteorological factors also appeared to be greater than those attributable to an IQR change in air pollutants., Conclusions: Both climatic variation and air pollution were associated with childhood allergic diseases, but the former appeared to play a more important role in the occurrence of these diseases. These findings may have significant implications for the development of tailored strategies to prevent these rapidly-increasing diseases worldwide., (Copyright © 2019. Published by Elsevier B.V.)