Phytolith Studies Research Articles

Luminescence and thermometry studies of plant opal phytoliths

We have investigated the luminescence properties of plant opal phytoliths to assess their suitability for determination of age and/or thermometric information from soil and sediment sequences. This study examined a <2.37 gcm−3 density fraction in parallel with quartz grains from samples collected from alluvial terraces. We observed comparable optically stimulated luminescence (OSL) from the phytolith fraction to the quartz, and thermoluminescence (TL) with broader peaks and continuum to higher temperatures. Scanning electron microscopy (SEM) data suggested the presence of opal clasts and contaminant minerals. To better understand the luminescence from opal phytoliths we analyzed a suite of biogenic materials including very pure diatoms, phytoliths, and quartz reference materials. We observe low sensitivity but measurable OSL signals in all the materials analyzed, and infrared stimulated luminescence (IRSL) signals with fast decay rates exceeding those of more typical feldspars in some of the purer materials. TL signals are similar to those observed for glasses and suggests dose response might extend beyond quartz saturation levels. Preliminary investigations of OSL dose response show very promising growth characteristics for opal phytolith samples and all other biogenic silica materials analyzed.

Phytoliths from modern plants in the Canary Islands as a reference for the reconstruction of long-term vegetation change and culture-environment interactions

The Canary Islands were the first part of the Macaronesian archipelago to have been settled by humans. The various ways in which the indigenous inhabitants and later European colonisers interacted with the native and endemic flora is a central topic for archaeologists, geographers and ecologists. Floristic changes can be studied from phytoliths which are plant microfossils with a high potential for preservation in sediment deposits and they can help reconstruct past ways of life and vegetation changes through time. However, there is no comprehensive and systematic study and reference collection of phytoliths produced by the flora of the Canary Islands, so far. To make a start with a first phytolith reference collection of a selection of plants relevant for the study of past socio-ecological interactions there, we processed over a hundred modern plant specimens collected on the islands of Tenerife, Gran Canaria and La Palma to obtain the phytoliths from them, using the dry-ashing method. We then described the phytolith morphologies, and counted the numbers of morphotypes for each species. We have categorised taxa according to their phytolith concentration and production of morphotypes with diagnostic potential. Our results suggest that among the selected taxa, species within the Arecaceae, Boraginaceae, Cyperaceae, Poaceae and Urticaceae families are the main native producers of phytoliths in the archipelago. We also identified phytoliths with diagnostic potential in particular species within the Asteraceae, Brassicaceae, Cistaceae, Euphorbiaceae, Lamiaceae, Lauraceae, Ranunculaceae and Rubiaceae. We discuss how phytolith assemblages can be interpreted in archaeological sites and sediment records. Our growing reference collection is a significant step towards the application of phytolith analysis to disentangle the long-term climatic and human-driven transformation of this biodiversity hotspot, as well as the cultural use of plant resources.

‘Paleoenvironmental study of modern charcoal making activity on forest soils in the Northern Vosges Mountains (Bitche, France): A multidisciplinary study of two remaining charcoal platforms and associated soils sequences’

AbstractThis multidisciplinary study aims to decipher the impact of ancient charcoal production on past and present‐day soils in the northern Vosges Mountains. Soil observations in the field and laboratory were complemented by charcoal and phytolith studies on large thin sections, molecular analyses of organic pollutants, and phytolith analysis on bulk samples. The complex technosol platform records an ancient natural soil sequence buried by a human‐made platform on which charcoal accumulated. The current upslope soil is an entic Podzol. Palaeoecological data collected in the buried soil are reliable owing to low bioactivity due to soil acidity. Podzolisation predated the platform construction. The presence of ashes induced low soil alkalisation developed in the charcoal hearth remains and appears to have generated the migration of subsequent iron/clay/organic bands throughout the platform sediment and the buried soil. Charcoal studied in thin sections revealed mainly Quercus and Fagus taxa. Phytolith studies suggest that a less dense or degraded forest preceded platform construction, probably due to former woodland coppicing or earlier disorganised wood gathering. The specific distribution of polycyclic aromatic hydrocarbons sorbed on charcoal has persisted in soils throughout centuries, but we have no evidence that charcoal‐making activities contributed to diffuse global pollution.

Wells, fields and the emergence of early-to-middle Holocene villages in the Huai River region, China: Contesting regional similarities and differences on prehistoric water management with new archaeological and palaeo-environmental evidence

The history of water management is closely intertwined with evolution of social structures. In particular, the emergence of rice farming and transition to sedentary life contributed significantly to the development of water management practices, with increasing labour and economic investments to build and operate water-management infrastructures. Here we present archaeological, archaeobotanical and geoarchaeological evidence of early water management obtained from the excavations of three early-to-middle Holocene sites in the upper and middle Huai River region (UMHR), including Hanjing from Sihong County of Jiangsu Province and Xielaozhuang and Zhangwangzhuang from Luohe City and Zhumadian City of Henan Province. Our 14C dates suggest multiple episodes of regional inhabitation in the UMHR region. Our results also reveal that the wells at Xielaozhuang represent some of the earliest attempts to ensure water consumption in the village, and importantly, the rice-field-like structures at Hanjing and Zhangwangzhuang are evidence of a more systematic effort to modify and transform local landscapes for rice cultivation and related economic activities. In line with the results from published phytolith studies, we found that the early experiment of rice cultivation altered local soil and hydrological conditions at these sites. These early forms of rice fields share some similarities in micro-and-macro- morphologies and represent successful adaptations to the low-lying plains that continued to have fluctuating hydrological regimes. The construction and operation of these wells, moats and rice-field-like structures stimulated collaboration beyond individual households and groups in these early-to-middle Holocene villages in the UMHR region and thus would have had profound social and economic ramifications.

A dataset for assessing phytolith data for implementation of the FAIR data principles

Phytolith research contributes to our understanding of plant-related studies such as plant use in archaeological contexts and past landscapes in palaeoecology. This multi-disciplinarity combined with the specificities of phytoliths themselves (multiplicity, redundancy, naming issues) produces a wide variety of methodologies. Combined with a lack of data sharing and transparency in published studies, it means data are hard to find and understand, and therefore difficult to reuse. This situation is challenging for phytolith researchers to collaborate from the same and different disciplines for improving methodologies and conducting meta-analyses. Implementing The FAIR Data principles (Findable, Accessible, Interoperable and Reusable) would improve transparency and accessibility for greater research data sustainability and reuse. This paper sets out the method used to conduct a FAIR assessment of existing phytolith data. We sampled and assessed 100 articles of phytolith research (2016–2020) in terms of the FAIR principles. The end goal of this project is to use the findings from this dataset to propose FAIR guidance for more sustainable publishing of data and research in phytolith studies.

Looking at Phytoliths in Archaeological Soil and Sediment Thin Sections

ABSTRACT Traditionally, phytolith research focusses on the study of bulk samples collected during archaeological field campaigns. However, phytoliths are frequently reported by soil micromorphologists studying their archaeological soil and sediment thin sections. Within these thin sections all components, including the phytoliths, are captured in the position they had in the original soil and sediment profiles. This opens perspectives towards a better understanding of phytolith depositional and post-depositional histories, but also towards the identification of invisible archaeological remains, such as previous vegetal floor covers. Furthermore, the study of phytoliths in thin sections opens up prospects for morphometrical analysis. Despite a series of limitations – the phytolith record is not concentrated, issues of visibility, the fact that phytoliths cannot be rotated and are cut at random angles – the study of phytoliths in thin sections is a rewarding effort. Beyond being a feasible task, it is also a promising asset, given a full integrative approach involving both phytolith specialists and micromorphologists.

Phytolith analyses of tropical plants and topsoil from western Peninsular Malaysia and their implications for paleoenvironmental reconstruction

The underrepresentation of many important rainforest species in pollen records still hinders accurate paleovegetation reconstructions in tropical Southeast Asia. In this study, we conducted a modern phytolith study of 141 plant and 15 surface soil samples around the forests of Jerai Hill in western Peninsular Malaysia to evaluate the potential of phytolith assemblages as a proxy for indicating tropical vegetation types. In the plant samples, including many Dipterocarpaceae species, tracheary annulate/helical phytoliths occur most commonly, followed by silicified epidermis, silicified stomata, elongate entire, sclereid, trichomes, irregular. A few diagnostic phytoliths with unique morphological features are found in dicotyledonous trees, palms, and ferns, such as spheroid ornate (sph_orn) and spheroid echinate (sph_ech). In contrast, the phytolith assemblage of surface sediment is dominated by sph_orn, sph_ech, and spheroid psilate. This suggests that similar to pollen, the contribution from dominating forest vegetation rich in Dipterocarpaceae species is obscure in phytolith deposits. However, phytolith analysis highlights the representation of monocotyledons and a few dicotyledonous trees. The more sensitive indication of Poaceae short-cell phytoliths than pollen for parent plants implies that their ratio to forest indicator phytoliths might be a valuable proxy of landscape openness. Additionally, the statistical analysis confirms that phytolith assemblages in the heath forest are slightly different from those in the lowland dipterocarp forest, exhibiting their potential to indicate various vegetation types.

A review of anatomical and phytolith studies of cystoliths: silica-calcium phytoliths in dicotyledonous angiosperms

Abstract Cystoliths are phytoliths of silica and calcium carbonate and are produced in a few groups of dicotyledonous angiosperms. Anatomical and, more recently, phytolith studies have recorded them in different families. In the present review, we analyse and integrate both types of research to compile information about their formation and composition, their distribution in vascular plants, their relation with anatomy and systematics and their potential roles in plant tissues. We also include analyses of specimens belonging to families having poorly-known cystolith information. According to our review, cystoliths can be considered to be Si-Ca phytoliths. They are well described in eight families, and in 14 other families the information is inconclusive. The production of cystoliths is limited to dicotyledons, but there is no clear phylogenetic relation between the families that produce them. Cystolith accumulation is predominantly in the epidermis of leaves and/or in parenchymatic rays of woods. Diverse roles related to photosynthesis enhancement and as Ca reservoirs have been assigned to cystoliths. Knowledge of cystolith production among vascular plants is relevant for anatomical, systematic and ecological research, and also for biogeochemical studies due to their importance as a source of Ca and Si.

Phytoliths in modern plants from Amazonia and the Neotropics at large: II. Enhancement of eudicotyledon reference collections

Phytolith studies of Neotropical vegetation history and its human influences require large modern reference collections from diverse woody and herbaceous plants. In order to further enlarge our reference collection, we analyzed phytoliths from 435 species of eudicotyledons from 84 families and 361 genera of mainly lowland Amazonian forest taxa along with other Neotropical plants. Our analysis revealed new morphologies from the silicification of bark in arboreal taxa that don't produce diagnostic vegetative phytoliths, as well as distinctive-looking phytoliths from leaves of previously unstudied trees. Several of the phytolith types uncovered here occur as unknowns in our earlier Amazonian terrestrial soil research. No morphotypes were revealed that overlapped with diagnostic phytoliths documented previously in other families and genera. Our reference collection now totals approximately 1540 Neotropical eudicotyledon species. For the Amazonian forest below 1000m it includes 80% of eudicotyledon families often with half or more of their genera and many of the most commonly occurring trees. A significant number of herbaceous and arboreal/woody taxa can be identified at the family, genus, and possibly species level for study of Neotropical vegetational and forest history. Phytolith and palynological investigations are excellent complements to each other.

Coprolites in Cemented Pleistocene Deposits on the Cape South Coast of South Africa

Helm, C.W.; Bamford, M.K.; Carr, A.S.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M.G.; Quick, L.J., and Stear, W., 2023. Coprolites in cemented Pleistocene deposits on the Cape south coast of South Africa. Journal of Coastal Research, 39(2), 221–233. Charlotte (North Carolina), ISSN 0749-0208. Ichnology, the study of trace fossils, has the potential to complement information from traditional body fossil studies. Six ichnosites, containing an array of features interpreted with varying degrees of confidence as vertebrate coprolites, have recently been identified on the Cape south coast of South Africa. They are embedded in Pleistocene deposits from Marine Isotope Stage 6 or 5e through Marine Isotope Stage 5a. Bovid, carnivoran, elephant, and reptile origins are inferred. In the majority of cases, vertebrate tracks occur in association with the coprolites. Petrography studies confirm an organic component in all samples, confirming the potential of coprolites to contribute to palaeoenvironmental reconstruction. Although initial palynology and phytolith studies were negative, a diligent search for further sites and further testing may help in realizing this potential. More broadly, the six ichnosites demonstrate the capacity of cemented dune and beach surfaces on the Cape south coast to preserve coprolites in open-air settings, compared with previously known coprolite records from carnivore dens and archaeological sites.

Variability in size and shape of polylobed leaf phytoliths in three populations of Dactylis glomerata L.

The article presents the results of morphometric study of polylobed trapeziform phytoliths of the leaf epidermis of Dactylis glomerata. The relevance of the study lies in the difficulty of establishing the limit of phytolith variability when using morphometry for paleoecological purposes. The studies were performed according to the recommendations of the International Committee for Phytolith Morphometry using the ImageJ software and its PhytolithsBatch plugin. For the first time, the characteristics of the parameters of the size and shape of polylobed trapeziform phytoliths are given. Previously, the study of these particles was not carried out due to their absence in cultivated cereals. The variability of the studied particles within populations and between representatives of individual populations is considered. The length of the phytolith and related indicators are subject to the greatest variability, the width and inscribed radius are the most stable.

Phytolith occluded organic carbon in Fagopyrum (Polygonaceae) plants: Insights on the carbon sink potential of cultivated buckwheat planting.

Crop cultivation has great potential to result in a phytolith carbon sink and can play important roles in the long-term stable carbon sequestration of terrestrial ecosystems. Buckwheat, an important multigrain crop with a very long cultivation history, is widely planted around the world. The phytolith carbon sink potential of buckwheat planting is still limited in the in-depth understanding of biogeochemical carbon sequestration in croplands. In order to estimate the phytolith carbon sink potential of buckwheat planting, in the present study, six species including 17 populations of Fagopyrum plants were selected as study materials. Firstly, their phytoliths were extracted using the wet oxidation method; then, the phytolith-occluded organic carbon (PhytOC) contents were determined using the spectrophotometry method; finally, the phytolith carbon sink potential of buckwheat planting was estimated. Results showed the following: 1) The PhytOC content range of the six Fagopyrum species studied was 0.006%~0.038%, which was significantly lower than that of rice, wheat, sugarcane, and some cereal and oil crops. There were significant differences in total silicon, phytolith, and PhytOC content of Fagopyrum plants among the different species, different organs (root, stem, and leaf), and different living forms (annual, partly perennial, and completely perennial). There were significant positive relationships between PhytOC and phytolith content and between phytolith and total silicon content. 2) The average phytolith carbon sequestration rate of Fagopyrum esculentum and Fagopyrum tataricum planting was 2.62 × 10-3 and 1.17 × 10-3t CO2 hm-2·a-1, respectively, being approximately equal to that of terrestrial shrub vegetation. 3) The global total amount of phytolith carbon sequestration of buckwheat planting reached 5,102.09 t CO2 in 2018, and the Chinese total amount of phytolith carbon sequestration of buckwheat cultivation was 624.79t CO2 in 2020. The phytolith carbon sink of buckwheat planting had significant potential for playing obvious roles in the carbon cycle. The present results are of great significance in crop phytolith studies and provide important references for phytolith carbon sink potential estimation of farmland ecosystems.

Understanding the formation of buried urban Anthrosols and Technosols: An integrated soil micromorphological and phytolith study of the Dark Earth on the Mundaneum site (Mons, Belgium)

Among the buried urban Anthrosols and Technosols, urban Dark Earth composes a major challenge to urban archaeologists and soil scientists. These homogeneous units are often the result of a complex formation history, involving human actions and natural processes. In order to understand the significance of the late medieval to pre-industrial urban Dark Earth observed on the site of Mundaneum in the historical centre of Mons (Belgium) an integrated soil micromorphological and phytolith study has been performed.The aim of this study is to understand how the urban Dark Earth formed and to identify the major natural and human processes that are involved in its formation. The results show that major natural processes are bioturbation, sedimentation, humification, alkalinisation and clay translocation. These processes are mainly human induced. Main human activities include cereal cultivation, horticulture, dumping of waste and trampling. Phytoliths proved to be an important witness of the presence of plant material, in a context where organic remains tend to decompose rapidly. The integrated approach allowed to come to a better understanding of the taphonomical history of the phytoliths, hence permitting to distinguish plant remains related to manure, cereal processing and in situ cultivated plants. The study further permitted the authors to gain insight in part of the biography of the site and its surroundings, hence showing changes in spatial organisation and the progressive urbanisation of the area. As such, this analysis provides an important stepstone to the further geoarchaeological study of town development in Medieval and Modern periods.

Evidence of prehistoric and early medieval agriculture and its impact on soil and land relief transformation in the Białowieża natural forest (NE Poland)

The Białowieża Forest is one of the few relics of temperate, old-growth woodlands in Europe considered “natural”. Recent research revealed there the presence of numerous anthropogenic landforms associated with prehistoric, medieval and modern-era human activities. They include systems of rectangular plots separated by embankments – linear forms up to several dozen centimetres high, well distinctive in airborne laser scanning visualizations but relatively poorly visible in the landscape. The field system at the archaeological site of Postołowo, located on a gentle slope currently entirely covered by a mixed forest (Carpinion betuli dominant), was selected for detailed study. The soils of the former arable fields and field boundary embankments were investigated using a multi-proxy approach, including analyses of soil micromorphology, soil physical and chemical properties, as well as sedimentological, archaeological, plant macro-remains and phytolith studies and radiocarbon dating. The objectives were to assess the impact of suspected past agriculture on soils and land relief and to establish a chronology of land use. Evidence of ancient vegetation clearance by burning was confirmed and two distinct episodes of cereal cultivation (including rye), without intensive manuring were dated in the Roman Period (ca 2nd century AD) and in the Early Middle Ages (ca 10th century AD). In the latter case, agriculture triggered soil erosion that led to accumulation of slope deposits; at least some of the field banks accumulated and/or were constructed during this period. Altogether, past agriculture resulted in spatial differentiation of soil morphology: with Brunic Arenosols in the upper parts of the slope and Brunic Umbrisols downslope. It is hypothesized that ancient cultivation in the Białowieża Forest evidenced by the remains of field systems, was limited to relatively short chronological periods and was restricted to certain land patches (microregions) surrounded by unused, forested terrain.

Palm springs on the Rio Grande: Insight into Archaic forager plant use from phytoliths recovered from a Late Holocene alluvial section in northern New Mexico.

In this study we present new evidence from phytolith studies for the presence of Sabal sp. (likely minor), an allochthonous plant, around Tesuque Creek in northern New Mexico during the early part of the Late Holocene, in the vicinity of known Late Archaic hunter-gatherer communities using the area at that time. We analyzed phytoliths from sediments taken from an alluvial section on the east side of Tesuque Creek dating to c. 3600–2400 cal. BP. The phytoliths demonstrated a change over time from a succulent dominated landscape to a shrubby one, with the later introduction of high densities of palmetto phytoliths associated with marshy deposits and adjacent burn levels. This evidence suggests a more diverse resource landscape available to local hunter-gatherer groups than previously understood, and may have implications for the early management of microenvironments, plant communities. This evidence demonstrates the value of phytolith analysis from alluvial sections for understanding human land and plant use practices over time. Our study provides a new perspective on what resources and land use areas were available for Archaic peoples inhabiting the area, and how they may have experimented with managing lesser known types of wild plant resources before the establishment of the triad of crops from Mesoamerica. This opens up new avenues for understanding the landscapes, land use practices, and environmental impacts of pre-agricultural communities in the northern Rio Grande and in other semi-arid environments worldwide.

Reconstructing agro-pastoral practice in the Mesopotamian-Zagros borderlands: Insights from phytolith and FTIR analysis of a dung-rich deposit

Understanding everyday agro-pastoral practice is critical for reconstructing the formation and maintenance of ancient societies. The ancient Near East (Southwest Asia) has one of the longest histories of agro-pastoral practice and one of the richest textual datasets anywhere on the globe. Yet, our knowledge of local, day-to-day agro-pastoral management strategies remains conjectural in many regions of Southwest Asia during the Bronze Age (late 4th–2nd millennium BCE). In this study we used phytoliths, dung spherulites, and Fourier Transform Infrared (FTIR) spectroscopy to identify and examine dung-rich sediments from Khani Masi, a mid-second millennium BCE Kassite site located in the Kurdish Region of Iraq. While micro-remain and geochemical approaches have not yet been widely applied in Mesopotamia (Ancient Iraq), they have the potential to shed light on the production systems supporting its Bronze Age cities, states, and empires. Our aim was to investigate (1) the range of local pastoral management strategies, (2) the degree of integration between agricultural and pastoral practice, and (3) the presence of signals related to the local ecology, seasonality, and environmental change and continuity.Phytolith results indicate that sheep-goat herds were primarily free grazed on wild grasses. The dominance of wild grass inflorescences, a potentially strong seasonality indicator, may suggest transhumant pastoralism. However, further evidence, including occasional foddering with cereal chaff, a diverse range of crop types, and significant accumulation of burnt dung within the site, collectively suggests a closely linked local agro-pastoral subsistence economy. This study provides much-needed empirical botanical data as well as productive insights for future application of phytolith studies in the Mesopotamian region, and sheds new light on agro-pastoral practice in the Zagros foothills during the second millennium BCE Kassite period.

REGISTRO PALEOBOTÁNICO DEL PLIO–PLEISTOCENO INFERIOR EN EL VALLE DEL RÍO URUGUAY. CARACTERIZACIÓN FITOLÍTICA DE LA FORMACIÓN SAN SALVADOR, ESTE DE LA PROVINCIA DE ENTRE RÍOS, ARGENTINA.

The San Salvador Formation is one of the few deposits from the Pliocene–Lower Pleistocene in the east of Entre Rios Province, which from a palaeontological point of view has been described exclusively through its phytolith content. This contribution includes the synthesis and expansion of this knowledge through the results of the phytolith study of the Jose Etchepare Hijo profile (Colon Department, Entre Rios). For this, an ad-hoc methodology has been used, adapted to obtain phytoliths in fluvial deposits. The sedimentary sequences were characterized by a succession of conglomerate supported matrix strata, fine to coarse sandy facies and fine facies (represented by clays and silts). The results allowed to observe a greater abundance and variability of phytoliths in layers with sandy texture; and proportionally more scarce and even absent in the gravel texture layers. Non-diagnostic grass phytoliths were common in all the samples with microremain materials, while among those of smaller size and diagnostic ones, their presence was manifested only in certain sectors of the profile. The phytolith assemblages were made up of elements from the Arecaceae, Poaceae (Bambusoideae, Panicoideae, Danthonioideae, Chloridoideae and Pooideae), and Podostemaceae families; and they have allowed inferring palaeocommunities of stratified hygrophilous forests, palm groves and riparian forests, which indicate a humid tropical-subtropical climate, with great water availability.

An in situ and morphometric study of maize (Zea mays L.) cob rondel phytoliths from Southwestern North American landraces

We present the first comprehensive computer-assisted morphometric analysis of microscopic rondel11As per the International Code for Phytolith Nomenclature 2.0 the names of recognized phytolith morphotypes are written in small caps in this report (Neumann et al., 2019). phytoliths (plant opal microfossils) produced in the cobs of 24 historic Southwestern North American landraces of maize (Zea mays L.) after all were grown in a well-documented agronomic field study. We also present an in situ study of the location of rondel phytolith production within the maize cob and provide a detailed review of previous maize phytolith studies. We found that glumes contained abundant rondel phytoliths throughout the tissue; however, lemma/palea tissue contained no phytoliths. In contrast, cupule tissue had some areas with abundant phytoliths, some with fewer scattered phytoliths, and vast areas that contained no rondel phytoliths. The rondel-rich areas appear to be where the glumes had once attached to the cupule and may be remnants of glume tissue adhering to the cupule. From the morphometric study, we found there were significant differences in the size morphometries of glume rondels depending on their cob location (top, middle, base) but no significant differences in shape morphometries. Using shape morphometries, we could not discriminate reliably among maize cob rondel phytoliths produced by the diverse landraces considered. The inclusion of morphometrics from areas in addition to or in combination with the outer periclinal surface may allow for some discrimination of maize landraces and is an avenue that should be explored further. Although our approach was not successful at identifying differences between essentially modern landraces, there may be significant rondel phytolith morphometric differences between wild, progenitor, and domesticated Zea.

Application of soil phytoliths to the quantitative characterization of temperate grassland ecosystems: a case study in Northeast China

Although phytolith analysis is a promising tool for reconstructing the palaeovegetation in grassland ecosystems, no phytolith study has yet attempted to quantitatively reconstruct the corresponding plant community characteristics. Questions remain regarding whether or not soil phytoliths can quantitatively reflect various aspects of grassland physiognomy, and how well modern phytoliths represent the quantitative characteristics of grassland ecosystems. These are important scientific issues in the field of phytolith analysis, which require further research on the modern phytoliths of grassland ecosystems. In order to explore the potential of phytolith analysis in the temperate grassland region, we have for the first time established a modern soil phytolith reference dataset by exploring the relationships between soil phytoliths and plant species inventory data from 77 sites in the Songnen grassland in Northeast China. The results show that phytolith assemblages can clearly distinguish Leymus chinensis grassland, Stipa grassland and mesophytic herb grassland. In addition, we found that the Ic phytolith index could discriminate samples of L. chinensis grassland from the other samples, while the Iph phytolith index proved to be less reliable in the region. In addition, in terms of quantitative plant community characteristics, the soil phytoliths showed a good correspondence with plant community cover and species richness, but not with biomass and diversity index. The transfer functions established in this study can provide reliable estimates of community cover and species richness in the Songnen grassland. In addition, phytoliths are shown to have the potential to reconstruct the taxonomic abundance of the aboveground plant community. This study is a major advance in the application of phytolith analysis to the quantitative estimation of plant community characteristics, and it provides a modern phytolith reference for the quantitative reconstruction of the paleovegetation of grassland ecosystems.

Could the grasses have played a role in the earliest salt exploitation? Phytoliths analysis of prehistoric salt spring from H\u0103l\u0103butoaia - \u0162olici (Romania)

The salt spring exploitation from Hălăbutoaia - Ţolici (Neamț County, Romania) dates back to the Early Neolithic and lasted throughout Chalcolithic. The deposit stratigraphy is estimated at 8 m and covers 2500 years of history (c. 6000–3500 BCE). In order to document the possible use of plants, particularly of the grasses, in the salt production process, we realized a detailed study of phytoliths preserved in several archaeological levels of Hălăbutoaia site. The most identified morphotypes come from grass family. Analysis revealed an important representation of inflorescence bracts phytoliths (especially Elongate dendritic) showing the anthropogenic origin of the assemblages. Bilobate are also well represented. These forms attest the presence of wild panicoid grasses (e.g. wild millet) and/or cultivated millets in the area. In some very punctual assemblages, forms produced by dicots are well represented. Considering the low phytoliths production by dicots plants, it involves a special accumulation of these types of plants that could be related to woody plants used as fuel for salt production. It is very possible that grasses had a very important role in pyrotechnology used to produce salt, either as the main fuel or as a mean for controlling the temperature or even as a firelighter.