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Holocene paleoclimate reconstructions and comparisons largely rely on accurate age-depth modeling. However, uncertainties in chronology, such as those caused by sparse radiocarbon dates, will hamper inter-core comparisons and correlations, and might result in misleading "cause and consequence" conclusions. This study aimed to find a solution to increase the comparability and minimize the uncertainty of wetland chronology as much as possible. Sediment cores were recovered and radiocarbon dated from the Lianhuachi wetland located in Southeastern China. Humification degree and loss-on-ignition (LOI) were determined using colorimetric and combustion methods respectively. Our data were compared with previously published datasets obtained in the same wetland. The results show that independent humification profiles from the Lianhuachi wetland displayed high similarities. This high similarity between the humification profiles allowed us to transfer radiocarbon ages from one core to another using sequence slotting correlation. Applying the humification-based chronology refinement method to all sediment cores resulted in an improvement in the correlation coefficients between the same but independently measured proxy sequences from the wetland, which suggests both the inter- and intra-core comparability was improved. Because determining peat humification degree is easy, inexpensive, and time-saving, we suggest that humification can serve as a tool that can be used to correlate different cores and to transfer published radiocarbon ages within the same wetland (peatland) or in a comparable geological setting, to establish a more robust chronology of these comparable cores. The degree of peat humification can thus serve as a relative dating technique to refine the chronology of wetland (including peatland) records. [ABSTRACT FROM AUTHOR]

Since the completion of first‐phase projects on the eastern and middle routes of the South‐to‐North Water Diversion (SNWD), the design and implementation of water pricing mechanism have become the key factors that affect the project operation. This paper launches the evaluation of implementation effect on the water price policy of the SNWD built projects in 2018 by coordinating the consumption of transfer water, allocation of receiving‐areas' water resources, collection of water fee for transfer water, as well as the implementation of local water price policies, which mainly exerted a comprehensive and interactive influence on the water price policy. Based on a series of data statistics and analysis, the usage of water transferred from the Yangtze River, improvement of regional water resources allocation, collection of water fee, and the implementation results of local water price policies were systematically analyzed. The main conclusions and corresponding suggestions were put forward to provide useful references on the formulation of water price policies for the design, optimization, and adjustment of the subsequent water pricing mechanism in the SNWD project. [ABSTRACT FROM AUTHOR]

The southeastern China coast is a region of special interest in the study of past and present relative sea-level change, given its distal location from giant ice sheets (far-field regions). During the past decades, a large number of biological, geological, and archaeological sea-level indicators have been retrieved from the Fujian coastal region which allows for recalibration and recalculation of sea-level index points (SLIPs). This study constructs a database of Holocene relative sea-level (RSL) observations for the Fujian coast, southeastern China. The database contains 59 quality-controlled SLIPs which show that RSL for the Fujian coast did not exceed present (0 m) during the Holocene, except potentially during 7.5–5.5 cal. kyr BP and 1.8–0.7 cal. kyr BP. Rates of RSL change were highest during the early Holocene and have decreased over time, due to the diminishing response of the Earth's mantle to glacial isostatic adjustment (GIA) and reduction of meltwater input. A series of sea-level oscillations were recorded in our SLIPs-based reconstructions which might correspond to global climate warming or cooling events. We assessed the spatial variability of RSL histories and compared these with the ICE-6G_C and ANU-ICE GIA model predictions. Substantial misfits between GIA predictions and regional RSL reconstructions were recognized: (1) the deceleration of the early-Holocene sea-level rise ended about one millennia earlier in the ICE-6G_C model than in the SLIPs-based reconstructions; (2) GIA model predictions show a mid-Holocene sea-level highstand of 1–3 m which is absent from our SLIPs-based reconstructions; and (3) all GIA model predicted a gradual RSL fall to 0 m since the middle Holocene, while our reconstruction displays significant RSL oscillations. It is presently unknown whether these misfits are caused by uncertainties in regional tectonic movement estimation or parameters used in the GIA models. Future applications of spatiotemporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of the ongoing acceleration of sea-level rise. • Holocene sea level index points (SLIPs) for the Fujian coast have been standardized. • SLIPs-based relative sea level (RSL) reconstructions are compared to model predictions. • Early-Holocene rapid RSL rise terminates earlier in models than in reconstructions. • Mid-Holocene highstands are captured in models but not obvious in the reconstruction. • Local tectonic and modelling parameter selection might have resulted in the misfits. [ABSTRACT FROM AUTHOR]

The plant growth regulator mepiquat chloride (1,1-dimethylpiperidinium chloride, DPC) has been successfully used worldwide in cotton production. Fortified DPC (DPC+) can slightly damage young tissues of the epidermis, which has shown potential in cotton chemical topping in China. The underlying mechanism remains unclear. We investigated whether apical meristem and leaf morpho-physiological traits contribute to delayed growth of the main stem and increased seed yield in DPC or DPC+ as a chemical inhibitor. Two different DPC-sensitive varieties (Xinluzao 60, L60; Jinken 1402, JK1402) were field-grown using three different topping treatments manual topping (MT), no topping (NT) and chemical topping (DPC+ and DPC) in irrigated arid lands of Xinjiang for two years. The plant height decreased by 1.4–13.6% for the DPC+ and DPC treatments compared with the NT treatment and increased by 3.8 –9.2% compared with the MT treatment. The thickness of the leaves, palisade tissue (Pt) and spongy tissue (St) increased by 5.1–21.5% under DPC treatment compared with other treatments. The 3-indoleacetic acid (IAA) content of the leaves significantly increased by 25.0–93.8% at 10 days under the DPC treatment compared with that under the MT and NT treatments. The zeatin riboside (ZR) content of the leaves and apical buds increased up to 7.5 times at 40 days under the DPC+ and DPC treatments compared with that under the NT treatment. The accumulation of reproductive organ biomass and proportion of reproductive organ dry matter to total dry matter under the DPC+ and DPC treatments increased by 2.0–39.7% compared with that under the MT and NT treatments. The seed cotton yield between the DPC+ and DPC treatments showed no significant difference. However, the seed cotton yield of JK1402 under the DPC+ and DPC treatments significantly increased by 9.5–11.7% compared with that under the MT and NT treatments. The main stem length was significantly correlated with the stem length of the upper part and gibberellin (GA) content in the apical buds. The leaf Pt and ZR contents were significantly correlated with the boll weight and seed cotton yield. Collectively, the data suggest that improved morpho-physiological traits of the apical part, such as an increase in the IAA and GA contents in the apical buds, leaf Pt and ZR contents, and boll weight, inhibited growth of the main stem and increased seed cotton yield for DPC, which is cheaper than DPC+ as a chemical inhibitor under chemical regulation during the whole growth period. • Chemical topping delays growth of the upper main stem. • Chemical topping enhances thickness and ZR contents of leaves. • DPC can increase boll weight and seed cotton yield in DPC-sensitive varieties. • DPC has the potential to replace manual and other chemical topping agents. [ABSTRACT FROM AUTHOR]

An improved understanding of past interactions between terrestrial vegetation and various forcings, such as climate change, human impact, and paleofire, is crucial for assessing impacts of future global change on terrestrial ecosystems. This study seeks to find the key factor or factors that have driven Holocene vegetation change along the East Asian monsoon margin. Several high-resolution pollen records are reviewed and new phytolith-based paleovegetation reconstructions and physical geochemical datasets are presented from a peatland in northeastern China. Using 108 modern topsoil samples as a training set, canopy cover and vegetation composition are estimated for the period since 5100 cal. yr BP. Variation partitioning analysis (VPA) is used to determine the relative importance of climate change, human impacts, and paleofire disturbance. The generalized dynamic vegetation model LPJ-GUESS is forced with climate anomaly output from an atmospheric general circulation model to simulate vegetation dynamics during the mid-Holocene and the pre-industrial era. The proxy-based estimates are compared to modelling output. Results indicate that regional tree cover varied from 10% to 40% during the past five millennia. The single-core, phytolith-based reconstructions are generally consistent with stacked tree pollen z-scores calculated from different records along the East Asian monsoon margin, implying that mid-Holocene tree cover decrease was persistent and almost synchronous over extensive areas. VPA demonstrates that long-term monsoon marginal vegetation successions were mainly caused by climate effects. Numerical modelling suggests that since the mid-Holocene the retreat of forests along the monsoon margin was primarily associated with precipitation deficits. Our investigation highlights that the precipitation associated with the East Asian monsoon system has exerted a stronger influence than the westerlies on the monsoon margin climate and vegetation change. With ongoing global change, close attention to variations in precipitation patterns and amounts should be especially helpful in efforts aimed at ecological monitoring, change prediction, and restoration. • Phytoliths provide complementary paleovegetation evidence to pollen for the monsoon margin area in northeastern China. • Phytolith-based quantitative tree coverage reconstructions suggest persistent forest cover since the mid-Holocene. • Vegetation dynamics within the monsoon margin area is strongly associated with East Asian monsoon variability. • DGVMs modelling suggests the dominant role of precipitation in regulating vegetation change. [ABSTRACT FROM AUTHOR]

Modern process research on phytoliths, including on the characteristics and spatial distribution of phytoliths assemblages and their relationship with environmental factors, is the basis of the use of phytoliths in paleoenvironmental reconstruction. We collected 54 surface soil samples along the isohyet of 600 mm in Northeast China in order to determine the relationship between modern phytoliths distributions and temperature. These were comprised by 20 samples from Xiaoxing'an Mountains, 32 samples from Songliao Plain, and 2 samples from Liaoxi Hills. The main phytoliths types were elongate and lanceolate, followed by short cell phytoliths, blocky, tabular and cuneiform; the percentages of the other types were all less than 1% and only occurred sporadically. There were significant differences in phytoliths assemblages among Xiaoxing'an Mountains, Songliao Plain, and Liaoxi Hills. Discriminant analysis was conducted using phytoiths assemblages, the samples from these three regions could be separated with a total accuracy of 96.30%. Elongate, lanceolate and pteridophyte‒type on average made up the largest proportion in Xiaoxing'an Mountains and the smallest in Liaoxi Hills, whereas saddle, bilobate and papillae showed the inverse trend; the proportions of blocky, tabular and cuneiform were the largest in Songliao Plain. The percentages of these types abovementioned were significantly different among the three regions. Correlation analysis revealed a significant negative correlation between the percentages of elongate, lanceolate and pteridophyte‒type and mean annual temperature (MAT), while there was a significant positive correlation between the percentages of blocky, tabular, cuneiform, saddle, bilobate, papillae and MAT. There was no significant relationship between rondel, trapeziform sinuate, conduit, carinate, sclereid, silicified stomata and MAT. A phytoliths index (C/W) based on the common phytoliths types in the surface soil samples which had a significant correlation with MAT was built. C/W = (elongate + lanceolate)/(elongate + lanceolate + blocky + tabular + cuneiform + saddle + bilobate). The values of C/W in Northeast China varied from 0.14 to 0.91, with an average of 0.67. The accuracy of the C/W index indicating climatic trends was significantly higher than the previously established Ic (climate index) and Iw (warm index). Overall, our results contribute to an improved understanding on the environmental significance of various phytoliths morphotypes, and provide a modern process foundation for phytoliths–based paleoclimatic reconstruction in the study region. [ABSTRACT FROM AUTHOR]

Recently, endorhizospheric microbiota is realized to be able to promote the secondary metabolism in medicinal plants, but the detailed metabolic regulation metabolisms and whether the promotion is influenced by environmental factors are unclear yet. Here, the major flavonoids and endophytic bacterial communities in various Glycyrrhiza uralensis Fisch. roots collected from seven distinct places in northwest China, as well as the edaphic conditions, were characterized and analyzed. It was found that the soil moisture and temperature might modulate the secondary metabolism in G. uralensis roots partially through some endophytes. One rationally isolated endophyte Rhizobium rhizolycopersici GUH21 was proved to promote the accumulation of isoliquiritin and glycyrrhizic acid significantly in roots of the potted G. uralensis under the relatively high-level watering and low temperature. Furthermore, we did the comparative transcriptome analysis of G. uralensis seedling roots in different treatments to investigate the detailed mechanisms of the environment-endophyte-plant interactions and found that the low temperature went hand in hand with the high-level watering to activate the aglycone biosynthesis in G. uralensis, while GUH21 and the high-level watering cooperatively promoted the in planta glucosyl unit production. Our study is of significance for the development of methods to rationally promote the medicinal plant quality. Key points: • Soil temperature and moisture related to isoliquiritin contents in Glycyrrhiza uralensis Fisch. • Soil temperature and moisture related to the hosts' endophytic bacterial community structures. • The causal relation among abiotic factors—endophytes—host was proved through the pot experiment. [ABSTRACT FROM AUTHOR]

Increasing use is being made of phytoliths for quantitative palaeovegetation and palaeoclimatic reconstruction, and consequently studies of phytolith transport are attracting increasing attention. In this context, we conducted a detailed study of factors affecting the soil phytolith transport in six representative natural soil types in Northeast China. We define a phytolith transport index (T) which indicates that transport rates are the lowest in chernozem and chestnut soils, intermediate in dark brown and albic soils, and obviously higher in black and alluvial soils. Additionally, there are differences in the vertical transport of different phytolith types in the soils; however, the transport characteristics are essentially the same among the different soil types. Transport rates are lowest for tabular and blocky phytoliths, followed by bulliform phytolith. By contrast, the rates for short cell, lanceolate and elongate phytoliths are significantly higher, and, notably, these phytolith types have different size and aspect ratios. The transport of phytoliths is also mainly influenced by mean annual precipitation (MAP), soil pH and soil clay content. Climatic factors, especially MAP, are a more significant factor for phytolith transport than phytolith size and aspect ratio. Overall, our findings are significant for the palaeoenvironmental interpretation of soil phytolith assemblages in topsoils. [ABSTRACT FROM AUTHOR]

Objective: To study the feasibility of a randomized controlled trial (RCT) comparing intrauterine insemination (IUI) with and without letrozole in couples with unexplained or mild male factor infertility STUDY DESIGN: We performed a randomized pilot study including 100 couples with unexplained or mild male factor infertility in the Reproductive Medicine Centre of Peking University Third Hospital in China. The couples scheduled for IUI were randomized to IUI with or without ovarian stimulation (letrozole) for up to 3 cycles within a time horizon of 4 months. Women in the letrozole group received 5 mg oral letrozole daily starting from cycle day 3-5 for 5 days. Women in the natural cycle IUI group did not receive any ovarian stimulation before IUI. The primary outcome is ongoing pregnancy leading to live birth. The study was registered under trial number NCT03455426 RESULTS: Between March 2018 and January 2019, 158 couples were eligible to participate after initial screening and 100 (63.3 %) couples agreed to participate. Of the 100 recruited couples, 50 were randomly allocated to IUI with letrozole and 50 to natural cycle IUI. Live birth occurred in 12 women (24.0 %) in the letrozole group and 10 women (20.0 %) in the natural cycle group (RR 1.20 (95 % CI 0.57-2.52)). Clinical pregnancy rates were 28 % and 26 % in the letrozole group and natural cycle group respectively (RR 1.08 (95 % CI 0.56-2.05). There were no multiple pregnancies in both groups. Patients were willing to be randomized and useful information was gained to plan a definitive trial.Conclusions: We showed that an RCT comparing IUI with letrozole versus natural cycle IUI in couples with unexplained or mild male factor infertility is feasible and acceptable. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) could improve crop yield by nutrient uptake from soil. However, how AMF of topsoil and subsoil respond to long-term differential application of mineral and organic fertilizers and how they are influenced in presence of different crops and growth stages have never been assessed together. Next generation sequencing was applied to profile soil AMF communities in both topsoil and subsoil from a typical arable soil (Eutric Regosol) in the Sichuan Base, southwest China. Soils were collected at anthesis and harvest of winter wheat and maize after 15-years of differential fertilization of an annual maize-wheat rotation (same inputs of nitrogen, N; but different in carbon, C; phosphorus, P; and potassium, K): (i) no-fertilization control (CT), (ii) 100% mineral NPK fertilizer (NPK), (iii) 60% mineral N and 100% mineral PK plus 40% N as crop residues (NPKCR); and (iv) 60% mineral N and 100% mineral PK plus 40% N as pig (organic) manure (NPKOM). Compared to CT, AMF diversity significantly decreased in topsoil, but increased in subsoil for both wheat and maize under NPK, NPKCR and NPKOM. The AMF community composition differed between NPK and CT in both topsoil and subsoil of maize and wheat. Both distance-based redundancy analysis (db-RDA) and structural equation modeling (SEM) suggested that AMF communities in topsoil and subsoil of maize and wheat responded in differences in soil available P, soil organic carbon, fertilization and climate (temperature and/or rainfall). Fertilization and available N, not AMF community, had significantly positive effects on wheat and maize aboveground dry matter and grain yield. Results from the present study shed light on how AMF communities in topsoil and subsoil respond to different soil fertility management over the long-term. Insights of this study are valuable in managing an important part of biological soil fertility. • AMF communities differed between fertilization regimes and soil depths. • AMF communities correlated with available phosphorus in topsoil and nitrogen in subsoil. • Soil organic carbon and rainfall correlated with AMF community Chao1 index and diversity. • Fertilization, but not AMF Chao1 index, determined plant biomass and grain yield. • AMF communities in subsoil were influenced by N fertilization. [ABSTRACT FROM AUTHOR]

Understanding local-scale paleoecological processes and their driving mechanisms is a major challenge in plant community ecology. However, phytolith records have the potential to retrieve localized signals of the evolution and patterns of past ecosystems. As a case study, we selected a forested region in Northeast China. We first established a modern phytolith reference dataset which enabled numerical estimates to be made of various aspects of the plant community. We then apply the dataset to a phytolith record from a sedimentary profile (HN) from the Changbai mountain region in order to quantitatively reconstruct the evolution of the vegetation since the last deglaciation. The results of partial least squares regression were used demonstrate that modern phytoliths can quantitatively estimate plant community coverage, species diversity and dry weight ratio; three numerical estimates respectively explained 62.3%, 50.3% and 49.5% of the variance. These quantitative relationships can provide reliable modern phytolith analogues for paleoecological reconstructions. The modern phytolith-based vegetation reconstruction indicates that the Changbai mountain region was dominated by forest communities since the late glacial period. The temporal development of the vegetation can be summarized as follows: boreal or coniferous forest, sparse and species-poor → mixed broadleaf-conifer forest, relatively dense and species-rich → mixed broadleaf-conifer forest, dense and species-rich. The phytolith-inferred changes in plant community coverage, dry weight ratio and species diversity correspond well with climatic changes. This supports the view that the environmental background mainly dominates ecosystem evolution, and it also confirms the utility of phytolith records to resolve local paleovegetation patterns and evolution. [ABSTRACT FROM AUTHOR]