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The coastal salt marsh wetland is mainly located in the tidal area where sea and land are intertwined, which has the functions of promoting silt and consolidating beach, wave reduction and disaster reduction, and is an ecological barrier against erosion in the coastal zone, which has important ecological value. Nevertheless, owing to the intricate nature of wetland species formation mechanisms and community distribution patterns, the impact of coastal squeeze on Suaeda salsa wetlands loss may not exhibit a linear relationship, necessitating further elucidation of the specific processes involved. Precisely understanding the extent to which coastal squeeze affects the threshold of loss in the Suaeda salsa wetland holds immense importance in safeguarding the distinctive red beach landscape. Furthermore, it represents a pivotal scientific challenge that necessitates resolution in the management of coastal wetlands for their protection and restoration. Hence, drawing upon the theoretical framework concerning the impact of coastal squeeze on the degradation of coastal Suaeda salsa wetland, this study employs the representative silty coastal region of China's northern Liaodong Bay as a case study to conduct empirical investigation. The research integrates Landsat imagery and digital elevation data, and incorporates spatial autocorrelation, elastic coefficient analysis, and barycenter model analysis to examine the threshold of degradation and spatial variations of Suaeda salsa wetland in response to coastal squeeze. The results show that: (1) The risk intensity of coastal squeeze in the study area exhibited a pattern of initial decline followed by an increase from 1995 to 2020, with the highest risk areas predominantly located in the development zone on the eastern bank of the Liao River Estuary. (2) There was a positive correlation between the growth of the coastal squeeze index and the loss of the Suaeda salsa wetland. When the proportion of area in which the coastal squeeze deteriorates reached 43.9%, the Suaeda salsa wetland lose resilience against the impact of coastal squeeze, leading to an intensified rate of loss. (3) Compared with the west side of the Liao River, the critical area of coastal squeeze and the loss barycenter of the Suaeda salsa wetland on the east side of the Liao River have a greater range of changes. The planning and management of coastal ecological restoration necessitates considering the occurrence conditions of the coastal squeeze impact threshold on the loss threshold of wetland and the migration characteristics of the wetland loss area. This approach enables the timely control of coastal squeeze risk intensity in the area and the preservation of wetlands' resistance to external disturbances. Consequently, it holds immense importance for the sustainable development of coastal wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

It focused on heavy metal pollution of green vegetation in Tuokexun County, Xinjiang Northwest China's suburban industrial area, using inductively coupled plasma emission spectrometer to analyze the samples for Mn, Ni, Zn, Cd, Hg, Pb, As, Cu, and Cr contents. The soil's heavy metal content in the study area indicated a minor level of pollution overall (P = 1.77), with the most severe contamination being Hg, which is more likely to be caused by human activities. Heavy metal elements in trees have the most stable composition in comparison to grass and shrubs, with varying concentrations across different vegetation. The concentrations of Mn, Cd and Hg were highest in the Haloxylon ammodendron, Ni in Morus alba, Pb, As and Cu in Nitraria tangutorums, and Cr in Phragmites australis. Heavy metal restoration is most effectively performed by shrubs, and there are disparities in heavy metal enrichment among various vegetation. No significant difference was found in heavy metal enrichment between the aboveground and underground parts of vegetation. Based on the average of the membership function, Tamarix exhibits the strongest ability to enrich heavy metals, while Nitraria tangutorum comes in second, and Cynanchum chinense R.Br. is the least effective among all plant species. Morus alba is recommended as the primary planting species in the area. Nitraria tangutorum and Haloxylon ammodendron have good potential for Cd and As restoration and can be used as supporting vegetation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have app eared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Liaohe coastal wetland has experienced severe degradation of Suaeda salsa (L.) Pall (S. salsa) in recent years. However, the impact of exogenous betaine (GB) on S. salsa growth remains unclear. Therefore, we conducted a natural simulated cultivation in soils of coastal wetland to investigate the effects of GB on S. salsa growth. The results showed that GB increased the height and weight of S. salsa, and meanwhile stimulated the synthesis of endogenous betaine and amino acids, increased soluble sugars and elevated the activity of Na + , K + -ATPase (enhancing osmotic stability). In addition, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased, and malondialdehyde (MDA) and H 2 O 2 decreased correspondingly, thereby improving the antioxidant capacity. Overall, GB application significantly alleviated salt stress and effectively promoted S. salsa growth. This study first indicated the important role of GB in influencing S. salsa growth, offering potential strategies for remediation in coastal wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Coastal wetlands are being greatly affected by global climate change, and understanding how tides influence plant connectivity can provide a basis for plant conservation and wetland restoration decisions in degraded and at-risk areas. In our study, we quantified the structural and functional connectivity of Suaeda salsa in the Yellow River Delta and explored the impact of tidal action on connectivity. The results showed that plant structural connectivity increased with distance inland from the sea. Similarly, seed connectivity was enhanced but gene connectivity was diminished when moving inland. An increase in the tidal channel branching rate was associated with a significant reduction in plant structural connectivity, and tidal inundation frequency significantly promoted gene connectivity. Tidal action was found to reduce seed circulation and germination, but this effect was not significant. Overall, it was established that plant structural connectivity is not equivalent to functional connectivity and that the effects of tides on structural and functional connectivity are inconsistent. In terms of achieving effective plant connectivity, tides can promote connectivity. In addition, when studying plant connectivity, temporal and spatial scales should be considered. This study provides a more comprehensive and insightful understanding tidal drivers of plant connectivity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Biochar has the potential to improve soil properties and increase plant productivity. However, due to the different types of soil, plants, and environmental factors, the impact of biochar is likely to vary. We explored the impacts of biochar prepared from an invasive plant Spartina alterniflora on plant performance and soil characteristics in a simulated coastal wetland ecosystem. We investigated the impact of three application ratios (control, 1%, and 5%; weight ratio) of biochar on the germination and growth of a native plant Suaeda salsa, the nutrient content and microbial community characteristics of the rhizosphere soil under three flooding treatments (no flooding, episodic flooding, and continuous flooding). Biochar application had no impact on seed germination of S. salsa, but promoted its seedling growth (biomass, height, root length) and nitrogen content. Biochar application also enhanced soil nutrient content and affected soil microbial community characteristics. Seed germination and seedling growth of S. salsa were sensitive to flooding and were the best under episodic flooding. Notably, flooding inhibited the impact of biochar on S. salsa and rhizosphere soil. In conclusion, biochar can positively affect the growth of S. salsa and improve the quality of rhizosphere soil, especially under no flooding. Our findings highlight the possibility of applying biochar for the restoration of S. salsa in coastal wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Wetlands have attracted much attention due to releases of organophosphate esters (OPEs) and other emerging contaminants into this particular environment. Here, Suaeda salsa plants and wetland soils collected from Laizhou Bay, North China, were analyzed to investigate the levels, distribution, and soil-plant transfer of OPEs in these ecosystems. The Σ 18 OPEs concentrations ranged from 137 to 386 ng/g dry weight (dw), whereas in rhizosphere the concentrations were between 99.8 and 198 ng/g dw. Suaeda salsa rhizosphere could promote the absorption of OPEs in wetlands, and Suaeda salsa root presents a greater rate of absorption. The Σ 18 OPEs concentrations ranged from 32.9 to 56.8 ng/g dw in roots, 3.93 to 7.51 ng/g dw in stems, and 2.79 to 4.06 ng/g dw in leaves. Log RCFs, log TF r-s and log TF s-l showed no significant correlations with their log K OW , indicating the complexity of uptake and translocation in the natural environment. Predictive model for the OPEs availability to Suaeda salsa was established from the experimental data. The field-based BCFs of all OPEs were dependent on K OW , decreased with increasing K OW . This study provides important insights into the phytoremediation potential of OPEs using Suaeda salsa as an effective strategy and their role in environmental risk assessment of OPEs in wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Coastal wetlands are ecologically and economically important; however, they are currently faced with fragmentation and loss. Plants are a fundamental element of wetlands and previous researches have focused on wetland plant connectivity; however, these researches have been conducted at the landscape but not species level. Here, given that tidal flats are important areas in coastal wetlands, we investigated the connectivity characteristics of typical plant species and environmental factors in different wetland regions influenced by various tidal conditions to reveal vegetation connectivity and its relationship with environmental factors on a small-patch scale. We found that tides negatively affect plant connectivity because both the Tamarix chinensis and Suaeda salsa have the highest connectivity on river banks, which are not influenced by tides. Of two tidal regions, different tides conditions have different influence on two plant species. T. chinensis had higher connectivity in the supratidal zone, whereas S. salsa had higher connectivity in the intertidal zone. Besides, the soil water content and soil salinity were significantly different in the three regions, but the soil total nitrogen and phosphorous were not. Soil water content and soil salinity were two factors that significantly affected plant connectivity. Specifically, soil water content positively affected the connectivity of T. chinensis and S. salsa, whereas soil salinity negatively affected the connectivity of T. chinensis. Taken together, these results indicate that tidal conditions affect plant connectivity on a small-patch scale. River banks and supratidal zone are beneficial for the recovery and growth of T. chinensis, intertidal zone and river banks are more conducive to the recovery and growth of S. salsa. Based on the above research, this study provides insights that could be applied to vegetation restoration in coastal wetlands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Polybrominated diphenyl ethers (PBDEs) are the ubiquitous contaminants in the coastal wetlands, with high persistence and toxicity. Environmental behaviors of PBDEs in sediment-plant system is a hot research area, where much uncertainties still occurred in field environment. In this study, the sediments and Suaeda heteroptera were synchronously collected to investigate the bioaccumulation and translocation of PBDEs in Liaohe coastal wetland. Mean concentrations of PBDEs in sediments, roots, stems and leaves were 8.37, 6.64, 2.42 and 1.40 ng/g d.w., respectively. Tissue-specific accumulation of PBDEs were detected in Suaeda heteroptera, with predominant accumulation in roots. Congener patterns of PBDEs were similar between sediments and roots, demonstrating root uptake as the key pathway of PBDE bioaccumulation. The proportions of lower brominated congeners increased from roots to leaves, implying the congener-specific translocation. Meanwhile, the lower brominated congeners exhibited higher sediment-tissue bioaccumulation (AFs) and translocation factors (TFs) compared to higher brominated congeners in Suaeda heteroptera, further verifying their preferential translocation. AFs and TFs of PBDEs were both not correlated with their log K ow , which was inconsistent with those of laboratory studies, reflecting the complicated behaviors of PBDEs in field environment. This is the first comprehensive report on bioaccumulation and translocation of PBDEs within Suaeda heteroptera in Liaohe coastal wetland., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Estuarine wetland is the transitional interface linking terrestrial with marine ecosystems, and wetland microbes are crucial to the biogeochemical cycles of nutrients. The soil samples were collected in four seasons (spring, S1; summer, S2; autumn, S3; and winter, S4) from Suaeda wetland of Shuangtaizi River estuary, Northeast China, and the variations of bacterial community were evaluated by high-throughput sequencing. Soil properties presented a significant seasonal change, including pH, carbon (C) and total nitrogen (TN), and the microbial diversity, richness and structure also differed with seasons. Canonical correspondence analysis (CCA) and Mantel tests implied that soil pH, C and TN were the key factors structuring the microbial community. Gillisia (belonging to Bacteroidetes) and Woeseia (affiliating with Gammaproteobacteria) were the two primary components in the rhizosphere soils, displaying opposite variations with seasons. Based on PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) prediction, the xenobiotics biodegradation related genes exhibited a seasonal decline, while the majority of biomarker genes involved in nitrogen cycle showed an ascending trend. These findings could advance the understanding of rhizosphere microbiota of Suaeda in estuarine wetland., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Nickel and copper, as high toxic heavy metals (HMs), are the most serious contaminants in Jinchuan mining area, China. In this paper, the influence of combined HMs stress on the growth of widespread plant-S. salsa has been studied. The stress gradient of combined Ni-Cu was set based on the local environment and pre-experiment. Seed germination, growth, physiological characteristics of S. salsa were investigated by the control test, and its heavy metal bioaccumulation capacity was investigated by samples collected from field platform. The growth of S. salsa was promoted at lower concentration (≤40 mg/L) and inhibited at higher concentration (≥80 mg/L) under the single HMs stress and combined HMs stress (Cu20/Ni20). The malondialdehyde (MDA) content was increased with increasing concentration, and the soluble protein and free proline content in stress group were higher than that of in control group. Under single HMs stress, the peroxidase (POD) activity increased with increasing concentration; while under combined HMs stress, the POD activity increased initially and then reduced. Cu320 and Ni320 combined HMs stress inhibited the growth of S. salsa at all concentrations. The average translocation factors (TF) of S. salsa were greater than 1.00, and higher in leaves compared to stems. The results of bio-concentration factors (BCF) of S. salsa show that BCF of leaves were larger than that of roots and stems. At lower concentration, the combined HMs stress promoted the growth of S. salsa in comparison to single HMs stress, however, opposite results were obtained at higher concentration. Overall, S. salsa showed high tolerance to Cu and Ni and stronger capabilities of HMs uptake and translocation, and therefore, it can be used as an alternative plant for the bioremediation of heavy metal pollution in mining area.

In this paper, the effect and mechanism of Salicornia bigelovii Torr. plant salt (SPS) on blood pressure in Sprague Dawley (SD) rats were investigated. The results showed that the edible salt induced hypertension, but the SPS did not. Organ indices and Hematoxylin-Eosin (HE) staining analysis indicated that SPS had a protective effect on the kidney and liver. In comparison with the edible salt-treated group, nitric oxide (NO) content, angiotensin-II (Ang-II) and endothelin-1 (ET-1) levels in the serum of the SPS-treated group had no obvious changes, but serum creatinine concentration significantly decreased. Moreover, superoxide dismutase (SOD) and Na(+)-K(+)-ATPase activity increased while malondialdehyde (MDA) content decreased in the SPS-treated group. In conclusion, a long-term high salt intake could lead to hypertension. SPS, as a salt substitute, could increase the body's antioxidant ability to protect the kidney and liver from the damage caused by a high salt intake and effectively avoid the occurrence of hypertension.

Low-lying land, slow and gentle desert, and semi-mobile dune are the three different habitats of natural Haloxylon ammodendron community along the southeastern edge of Zhunger Basin in Xinjiang Uygur Autonomous Region. This paper studied the structural characters of H. ammodendron community from the aspects of species structure, species diversity, biomass, and distribution patterns of natural regeneration sapling. The results showed that the species of H. ammodendron community was the richest on low-lying land, the second on slow and gentle desert, and the least on semi-mobile dune. The number of plant species in the three different habitats was 16, 15 and 12, respectively. The amount of H. ammodendron natural regeneration sapling was the largest (6 687 trees x hm(-2)) on semi-mobile dune, but its distribution was not even. Low-lying land had a slightly smaller amount (5 799 trees x hm(-2)) of H. ammodendron natural regeneration sapling than semi-mobile dune, but the distribution of the sapling was more even. The overall evaluation ion was that the natural regeneration of H. ammodendron community was the best on low-lying land. Its total biomass on low-lying land was 19.39 t x hm(-2), while that on slow and gentle desert and semi-mobile dune was 9.32 and 6.69 t x hm(-2), respectively. The distribution patterns of H. ammodendron natural regeneration sapling in different habitats were all aggregatice. The ground of low-lying land was fixed, with fairly good soil moisture and fertility, which was appropriate for the growth of H. ammodendron and the development of H. anmmodendron community, while that of slow and gentle desert and semi-mobile dune was easier to suffer from wind erosion, with poor soil moisture and fertility and fairly serious habitat conditions.

Background and Aims: Information on the initial growth characteristics of annuals found in Chinese deserts is very limited. The aim of this study was to investigate seed germination and interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in three annuals (Agriophyllum squarrosum, Bassia dasyphylla and Aristida adscensionis) commonly growing on sand dunes in these regions., Methods: Effects of temperature, light and polyethylene glycol-6000 on seed germination were examined by irrigating seeds sown on filter paper in Petri dishes. Seedling emergence was examined for seeds sown on the surface of, or at different depths (5, 10, 20, 30, 40 and 50 mm) in, sand-filled pots, which were irrigated under different regimes. For seeds buried at a depth of 50 mm, seed viability was examined after irrigation of the pots., Key Results: Seeds of three species germinated at most temperatures recorded between spring and autumn in their native habitats. No seed dormancy was found in any species. For all three species, seedling emergence was most favoured when seeds were buried at a depth of 10 mm. When seeds sown on the sand surface were irrigated, seed germination was considerably suppressed due to water deficiency, but many seeds remained viable. For A. squarrosum and B. dasyphylla, many seeds that were deeply buried and irrigated remained ungerminated but viable, while for A. adscensionis deeply buried seeds germinated, but the seedlings did not emerge due to unfavourable seedling growth in deep sand., Conclusions: Precipitation is the most crucial factor in determining the seasonal emergence of seedlings of the three tested species in the field. The vertical distribution of seeds in sand determines the proportion of seeds that germinate after precipitation and acts to maintain seed banks over multiple years.

Pollen analysis is one of the best and possible approaches for the quantitative reconstruction of paleobotany and paleoclimate, and discrimination of human activities. In this paper, we reveal the characteristics of pollen assemblages in different agricultural units and their spatial distribution of major pollen taxa in the Anyang area where the human influences are serious, so as to get more information about climate change and human activities from pollen records. The pollen assemblages of total 122 surface soil samples from different agricultural units (farm lands, vegetable plots, wastelands, cape-lands, woodlands, etc.) indicate that herbaceous pollen dominates the pollen assemblages with an average of 73%, mainly from Poaceae, Artemisia, Chenopodiaceae and Cruciferae; arboreal pollen percentages reach 18%, mainly from Pinus and Ulmus; shrub pollen and fern spores have very low percentages. In general, pollen assemblages are consistent with vegetation composition, though some differences also exist in different agricultural units. In farmlands and vegetable lands, Poaceae pollen has the highest percentages (averaging 27%) compared to other agricultural units with dominant corn or wheat pollen, while in wastelands and woodlands, arboreal and Artemisia pollen percentages have higher values (averaging 20% and 19% respectively). Cruciferae has the highest pollen percentages (70%) in rape-lands. Both pollen assemblages and PCoA can generally identify the vegetable plots, farmlands, woodlands, wastelands, and rape-lands. Pinus and Artemisia pollens mainly appear in the western part of Anyang, which is consistent with the parent plants; Poaceae pollen mainly exist in the eastern part with more farmlands; Chenopodiaceae pollen mainly appear in the urban areas and near major roads where human influences are stronger, Cruciferae pollen can mainly be found in the urban area and in the northwest part of Anyang where more vegetables are planted. [ABSTRACT FROM AUTHOR]

This paper presents the pollen assemblages from 108 surface sediment samples from 4 lakes (the Lake Daihai, Lake Hongjiannao, Lake Hulunnao and Lake Duikounao) in the monsoon fringe area of China. The herb pollen taxa Artemisia, Chenopodiaceae, Poaceae and Compositae are the major components of pollen assemblages of the 4 lakes and Pinus, Betula, Quercus, Ulmus, Populus, Ostryopsis and Elaeagnaceae are frequently presented, which reflect regional and local vegetation well. The mean similarity coefficients for samples from the Lake Daihai, Lake Hongjiannao, Lake Hulunnao and Lake Duikounao are 0.66 ± 0.17, 0.71 ± 0.11, 0.73 ± 0.12 and 0.67 ± 0.12 respectively, so pollen assemblages are relatively consistent in each lake, which shows that focusing and mixing effects have occurred before and after pollen deposition. However, pollen assemblages do differ between sampling sites in each lake. The largest difference is seen in the Lake Daihai, followed by the Lake Duikounao, Lake Hulunnao and Lake Hongjiannao (The mean Euclidean distance is 20.09±11.11, 11.22±3.64, 10.67±4.03 and 8.44± 4.51 respectively). These differences are possibly caused by the differences of focusing and mixing effects, pollen source areas, drainage areas and regional vegetation compositions. The Lake Daihai and Lake Hong jiannao have water deeper than 5 m and strong re-suspension, focusing and mixing effects occur in the lakeshore and shallow water areas, where pollen concentrations are lower than in deeper lake areas. In the Lake Hulunnao and Lake Duikounao, with depths less than 5 m, re-suspension and mixing effects are obvious across the whole lake area, so pollen assemblages and pollen concentrations are more consistent among sampling sites in each lake. Comparison between the lake samples and samples from the inflowing river reveals that wind is primary pollen transportation force in the Lake Hongjiannao, where the consistency of pollen assemblage is conspicuous, while there is greater variation in lakes where pollen input is dominated by waterborne sources. [ABSTRACT FROM AUTHOR]

The focus of this paper is on the reconstruction of the mid-Holocene climatic changes based on the pollen records contained in a 6.2 m thick section in the southern part of the Tengger Desert, northwestern China. To understand the modern analogues of the mid-Holocene changes, modern pollen spectra across different vegetation zones from the Qilian Mountains to the lowland Tengger Desert were studied first. Four pollen combinations were identified, corresponding to four different modern ecological environments: (1) a Picea-Artemisia combination in a spruce forest and its vicinity; (2) an Artemisia-Chenopodiaceae-Gramineae-Salix combination in a mixture belt of montane grassland and poplar woodland; (3) a Chenopodiaceae-Artemisia-Nitraria combination in a desert steppe belt; and (4) an Elaeagnus-Artemisia-Chenopodiaceae-Nitraria combination in a desert riparian forest. Our study also shows that a relatively low percentage of Picea pollen (30–10%) seems to be associated with water transportation (alluvial deposits) and a very low percentage of Picea pollen (10–5%) appears to be related to long-distance air transportation. With references to the modern relationships between pollen assemblages and associated bioclimates, the pollen sequence covering the period between 8500 and 3000 cal. BP was used to infer the climatic change history. The results show that a warmer and drier climate dominated between 8500 and 7950 cal. BP. Subsequent decreases in Artemisia and warm desert forbs/shrubs taxa and contemporaneous fluctuating increases in montane coniferous and aquatics elements from 7950 to 7400 cal. BP reflect a fluctuating increase in humidity and/or a fluctuating decrease in temperature. The following period from 7400 to 5650 cal. BP was generally warm with the Holocene Climate Optimum occurring between 7400 and 6500 cal. BP. A remarkably cool spell followed between 6500 and 6300 cal. BP that was then succeeded by a warmer and more humid period between 6300 and 5650 cal. BP. The period between 5650 and 4450 cal. BP was characterized by drastic oscillations in climatic conditions with three humid and probably cold spells intervened by three relatively dry and warm spells. The period between 4450 and 3500 cal. BP was cold and humid, followed by a wet spell as indicated by a very high percentage of Typha pollen. [ABSTRACT FROM AUTHOR]

This paper presents a description of the river terrace at Tangjia Village in Lhasa, Tibet. Selected types of phytolith and pollen were used as proxies to study the paleoclimate in the study area. Ancient climate and vegetation changes since 10 ka BP were examined. The results demonstrated that between 10.2 and 8.9 ka BP, the dominating phytolith was the cold type and the dominating vegetation type was grassland-forest. This indicated that the climate changed from cool-humid to cool-dry and later turned back into a cool-humid climate. Between 8.9 and 8.1 ka BP, the main types of phytoliths were tooth, dumbbell, and polyhedral. This suggests that the vegetation consisted of forest-grassland and the period's climate had become warmer. Between 8.1 and 6.7 ka BP, the warm index of phytolith assembelage gradually increased, whereas the spore and pollen assembelage revealed that the vegetation was forest with hardwood. This suggested that the paleoclimate was warmest in this period. The herbaceous vegetation increased gradually, indicating that the climate had become colder since 7.5 ka BP. Between 6.7 and 4.6 ka BP, cold type phytolith such as tooth and cap were found. Simultaneously, the pollen assembelage indicated that the vegetation shifted from grassland to forest and then turned back into grassland. This implies that the climate fluctuated from cold-dry to cool-humid. Between 4.6 and 1.9 ka BP, the dominate type of phytolith was cold type and its warm index was in the range 0.04-0.28, suggesting a herbaceous vegetation cover and indicating that the climate was cold. The phytolith warm index from 1.9 ka BP revealed that the climate was continuously decreasing, and most of the pollen assembelage consisted of Chenopodiaceae and Artemisia. This conclusion is in agreement with the phytolith result that indicates that the climate was becoming colder and colder. [ABSTRACT FROM AUTHOR]

• Identify ancient flood events, which may be the reason for decline of the culture. • Pollen and heavy metals can be used to reflect the strength of human activities. • Pollen and heavy metals revealed the process of culture from prosperity to decline. • This paper defined the chronology from prosperity to decline of Shijiahe culture. • Climate change has been revealed by pollen and heavy metals since 4800 cal. yr BP. The Shijiahe Culture (ca. 4800–4100 yr BP), which originated in the middle Yangtze Basin, was a milestone of prehistoric Chinese civilization. To reveal the interactions between climatic changes and human activities during this time interval, the geochronology and multiple proxies (pollen and heavy metals) of samples from a 220-cm-deep outer wall at the Sanfangwan Site (a typical site of the Shijiahe Culture) were analyzed. Radiocarbon dating indicates that the age range of the Sanfangwan Site is ca. 4800 to 4100 cal. yr BP. From ca. 4800 to 4600 cal. yr BP (the early Shijiahe Culture), pollen assemblages were dominated by Gramineae and an anthropogenic plant community (e.g. Ranunculaceae, Chenopodiaceae, Labiatae, and Cruciferae), indicating an expansion in rice agriculture during this interval. High metal concentrations in the same interval indicate a large flux of metals from smelting and farming activities. Between ca. 4600 and 4100 cal. yr BP (the middle and late Shijiahe Culture), decreases in Gramineae and anthropogenic pollen mirrored the recession of farming. Concurrent decreases in heavy metals may be attributable to a decline in the smelting industry. Three episodes of high pollen concentrations and visible increases in hygrophyte pollen, Pinus pollen, and fern spores at 4600–4550, 4450–4350, and 4200–4100 cal. yr BP probably indicate the occurrence of several flooding events during the middle and late Shijiahe Culture, resulting in the migration of local inhabitants. This study highlights the driving effect of flood events on the collapse of the Shijiahe Culture. [ABSTRACT FROM AUTHOR]

Aims The Nihewan Basin of North China, considered the cradle of Eastern civilization, contains a set of late Cenozoic strata and artifacts used by Homo erectus in the early Pleistocene (~1.66 Ma to 780 ka) and the cranial bones and teeth of early H. sapiens from the late middle Pleistocene (~370 to 260 ka). Palynological studies provide an opportunity to explore the living environment of early humans. Methods Palynological samples from the Hutouliang Section (~603–587 ka) of the Xiaodukou Formation of the Nihewan Basin were treated by heavy liquid flotation. Based on the palynological assemblages from the section, vegetation and climate in the Nihewan Basin were reconstructed. Important Findings The dynamic vegetation changed from temperate needle- and broad-leaved mixed forest-steppe (mainly Picea , Abies , Betula , Juglans , Artemisia and Chenopodiaceae) to conifer forest (mainly Pinus , Picea and Abies), which saw the replacement of H. erectus by early H. sapiens. The comparison of the Nihewan Basin with other human sites around the world during the same period reveals that early humans preferred to live in caves, accompanied by relatively open steppe or forest-steppe environments, inhabited by numerous mammals. Therefore, it is inferred that the emergence of dense conifer forest and the disappearance of open steppe environments in the Nihewan Basin at approximately 603–587 ka provide new evidence that early humans followed most mammals to steppe or forest-steppe environments and thus left the Nihewan Basin. These new findings not only enrich our knowledge of early human behavior, such as their diet, migration and settlement, but also fill in gaps in paleovegetation and paleoenvironmental research in the Nihewan Basin during the middle Pleistocene (780–400 ka). [ABSTRACT FROM AUTHOR]

Two new species of Dzhanokmenia Kostjukov (Hymenoptera: Eulophidae: Tetrastichinae), D. stefaniolae Li, Wang & Hu, sp. nov. and D. yuxuannis Li, Wang & Hu, sp. nov., are described and illustrated from Xinjiang Uyghur Autonomous Region, China. D. stefaniolae was reared from stem-galls made by Stefaniola sp. (Diptera: Cecidomyiidae) on black saxaul, Haloxylon ammodendron (Chenopodiaceae); D. yuxuannis was collected by sweeping from both black saxaul and white saxaul, H. persicum, in Beishawo Desert near Fukang. A key to females of all known species of Dzhanokmenia is provided. [ABSTRACT FROM AUTHOR]

Background: Suaeda glauca, a succulent halophyte of the Chenopodiaceae family, is widely distributed in coastal areas of China. Suaeda glauca is highly resistant to salt and alkali stresses. In the present study, the salt-responsive transcriptome of Suaeda glauca was analyzed to identify genes involved in salt tolerance and study halophilic mechanisms in this halophyte. Results: Illumina HiSeq 2500 was used to sequence cDNA libraries from salt-treated and control samples with three replicates each treatment. De novo assembly of the six transcriptomes identified 75,445 unigenes. A total of 23,901 (31.68%) unigenes were annotated. Compared with transcriptomes from the three salt-treated and three salt-free samples, 231 differentially expressed genes (DEGs) were detected (including 130 up-regulated genes and 101 down-regulated genes), and 195 unigenes were functionally annotated. Based on the Gene Ontology (GO), Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) classifications of the DEGs, more attention should be paid to transcripts associated with signal transduction, transporters, the cell wall and growth, defense metabolism and transcription factors involved in salt tolerance. Conclusions: This report provides a genome-wide transcriptional analysis of a halophyte, Suaeda glauca, under salt stress. Further studies of the genetic basis of salt tolerance in halophytes are warranted. [ABSTRACT FROM AUTHOR]

The Relative Pollen Productivities (RPPs) of common steppe species are estimated using Extended R-value (ERV) model based on pollen analysis and vegetation survey of 30 surface soil samples from typical steppe area of northern China. Artemisia, Chenopodiaceae, Poaceae, Cyperaceae, and Asteraceae are the dominant pollen types in pollen assemblages, reflecting the typical steppe communities well. The five dominant pollen types and six common types ( Thalictrum, Iridaceae, Potentilla, Ephedra, Brassicaceae, and Ulmus) have strong wind transport abilities; the estimated Relevant Source Area of Pollen (RSAP) is ca. 1000 m when the sediment basin radius is set at 0.5 m. Ulmus, Artemisia, Brassicaceae, Chenopodiaceae, and Thalictrum have relative high RPPs; Poaceae, Cyperaceae, Potentilla, and Ephedra pollen have moderate RPPs; Asteraceae and Iridaceae have low RPPs. The reliability test of RPPs revealed that most of the RPPs are reliable in past vegetation reconstruction. However, the RPPs of Asteraceae and Iridaceae are obviously underestimated, and those of Poaceae, Chenopodiaceae, and Ephedra are either slightly underestimated or slightly overestimated, suggesting that those RPPs should be considered with caution. These RPPs were applied to estimating plant abundances for two fossil pollen spectra (from the Lake Bayanchagan and Lake Haoluku) covering the Holocene in typical steppe area, using the 'Regional Estimates of Vegetation Abundance from Large Sites' (REVEALS) model. The RPPs-based vegetation reconstruction revealed that meadow-steppe dominated by Poaceae, Cyperaceae, and Artemisia plants flourished in this area before 6500-5600 cal yr BP, and then was replaced by present typical steppe. [ABSTRACT FROM AUTHOR]

Studies of the modern relationship between pollen, vegetation and land-use are essential to infer past human impact on vegetation from pollen records. Nevertheless, such investigations are relatively few in China. We present here a study of pollen assemblages from sediment samples collected from irrigation pools in the Tuoliang and Qipanshan catchments in northern China. Pollen and spores from natural vegetation such as Artemisia, Chenopodiaceae, Pinus and Selaginella sinensis dominate the pollen assemblages, while pollen types which could be from crops such as cereals, Brassicaceae, Fabaceae, Solanaceae, Apiaceae and Cucurbitaceae are common but not abundant. Pollen percentages of Artemisia and Chenopodiaceae become less with decreasing altitude, while Pinus and S. sinensis percentages increase, indicating that saccate Pinus pollen and S. sinensis spores are transported further than non-saccate Artemisia and Chenopodiaceae pollen, and differential sorting of pollen is occurring during transport in river water. Proportions of pollen from farmland and crops increase with decreasing altitude, showing that pollen percentages of crops might be a good indicator of the extent of farmland. A linear correlation analysis between pollen percentages and vegetation proportions shows that pollen percentages of crops are positively correlated with proportions of farmland, while correlation between pollen percentages of trees, shrubs and herbs and proportions of woodland, scrubland and grassland respectively is poor. This study indicates that the relationship between pollen percentages and vegetation proportions can be explained by the differences of pollen productivity, dispersal and deposition, and might be the basis for a modelling approach to infer past vegetation cover in northern China. [ABSTRACT FROM AUTHOR]

The Artemisia/Chenopodiaceae (A/C) ratio is assumed to be a useful index for reconstructing moisture changes in arid and semi-arid regions. Thorough modern pollen studies are still lacking to understand the reliability and limitation of A/C ratio as a moisture indicator, however. Here we review how well this ratio can be applied in arid and semi-arid China on the basis of new surface pollen data, previous data synthesis and other publications. Results indicate that variance in the A/C ratio can permit identification of modern vegetation types and that the A/C ratio generally has a positive relationship with annual precipitation. However, soil salinity, vegetation community composition, human activity and sample provenance (e.g. soil and lake sediments) will affect the values of the A/C ratio in different vegetation zones and therefore the A/C ratio is not comparable in different regions. We argue that the A/C ratio can only be used to reconstruct vegetation types and climate change in regions with precipitation <450–500 mm, and in steppe, steppe desert and desert areas. Careful studies should be undertaken to understand the modern pollen–vegetation–climate relationships in various regions before using the A/C ratio to interpret vegetation and climate. [ABSTRACT FROM AUTHOR]

greenhouse experiment was conducted to determine the effects of sediment burial on survival, growth and dry mass allocation of seedlings of Suaeda salsa (L.) Pall. (Chenopodiaceae), an important pioneer species of tidal wetland near the Yellow River estuary. From April to June 2009, seeds were buried at 0.5 cm depth in plastic pots filled with sediment. Two weeks after emergence, seedlings were buried to depths of 0 (H0), 33% (H33), 67% (H67), 100% (H100) and 133% (H133) of their mean height. Results showed that seedling survivorship, height, absolute height growth rate, relative height growth rate, stem diameter, number and length of branches, dry mass and relative growth rate were significantly affected by burial depth ( P < 0.01). Although dry mass allocations changed with increasing burial depth, allocations to root, stem and leaf were not significantly affected by burial depth ( P > 0.05). No seedlings died in the partial burial treatment, approximately 18.06 ± 5.32% seedlings survived when they were completely buried, and no seedling survived when the burial depth reached 133% of the seedling height. Seedling height, absolute height growth rate, relative height growth rate, stem diameter, number and length of branch, dry mass and relative growth rate in the partial burial treatments were much higher than those of the unburied and completely buried treatments. With increasing burial depth, there was a tendency that both allocation to root and allocation to leaf increased, while allocation to stem decreased. The stem of S. salsa formed adventitious roots after being buried for less than 4 weeks, which was favorable for the survival and growth of seedlings, reflecting the fact that the S. salsa seedlings indeed exhibit a special adaptive strategy against rapid sediment burial in tidal wetland. The burial experiment also indicated that moderate burial disturbance (H33 and H67) increased seedling vigor, while strong burial disturbance (H100) reduced seedling vigor. The use of thin-layer sediment burial to promote the vigor of plants in degraded wetland is very feasible, and our results provide valuable practical information applicable to the restoration of degraded S. salsa wetland. [ABSTRACT FROM AUTHOR]

The potential for marsh plants to be vectors in the transport of mercury species was studied in the natural, mature, tidal China Camp salt marsh on San Pablo Bay. The fluxes of organic matter, mercury (THg), and monomethylmercury (MeHg) were studied in natural stands of Spartina Jbliosa and Salicornia virginica. Seasonal fluxes from the sediment into aboveground biomass of live plants and subsequent transfer into the dead plant community by mortality were measured. Loss of THg and MeHg from the dead plant community through fragmentation, leaching, and excretion were calculated and were similar to net uptake. Seasonal data were added up to calculate annual mass balances. In S. foliosa, annual net production was 1,757 g DW m-2, and the annual net uptakes in the aboveground biomass were 305 μig THg m-2 and 5.720 μg MeHg m-2. In S. virginica, annual net production was 2,117 g DW m-2, and the annual net uptakes in aboveground biomass were 99.120 jig THg m-2 and 1.990 μtg MeHg m-2. Of both plant species studied, S. foliosa had a slightly lower production rate but greater mercury species uptake and loss rates than S. virginica, and, consequently, it is to be expected that S. foliosa matter may affect the local and possibly the regional food web relatively more than S. virginica. However, the actual effects of the input of mercury-species-containing plant-derived particulate matter into the food webs would depend on trophic level, food preference, seasonal cycle of the consumer, total sediment surface area vegetated, location of the vegetation in the marsh landscape, and estuary bay landscape. Since the levels of mercury species in dead plant material greatly exceed those in live plant material (on a dry weight basis), detritivores would ingest greater mercury species concentrations than herbivores, and consumers of S. foliosa would ingest more than consumers of S. virginica. The greatest THg and MeHg losses of both plant species due to mortality and to fragmentation-leaching-excretion occurred in late spring and early autumn, which corresponds to peak MeHg levels observed in sediments of coastal systems of previous studies, suggesting enhanced THg-MeHg export from the marsh to the nearshore sediment. [ABSTRACT FROM AUTHOR]

Halostachys caspica (Chenopodiaceae) is a halophytic shrub commonly found in saline areas of the western deserts in China that produces small-sized seeds (0.07 mg). Effects of temperature, light, NaCl, and polyethylene glycol-6000 on seed germination were investigated by incubating seeds in Petri dishes in controlled environments. Seed germination was promoted by both light and temperature alternation. Seed dormancy was not detected. Temperature dependence of seed germination indicated that H. caspica seeds are able to germinate at any time between spring and autumn in their habitats in China. Seed germination was almost completely withheld when seeds were moistened with 500 mmol kg-1 NaCl, but seeds remained viable after moistening with 3000 mmol kg-1 NaCl for 41 d. Opportunities for seed germination were expected to be very limited in the field because for photoblastic H. caspica seeds to germinate, the seeds need to be almost exposed to the soil surface, where they are likely to suffer severe water deficiency and high salinity. It was suggested that germination of H. caspica seeds in the field is facilitated by a supply of a large amount of water from melting snow in early spring. [ABSTRACT FROM AUTHOR]