A Review on Diagnostic Phytoliths for the Application in Paleovegetation Reconstruction and Environmental Archaeology in East Asia

Phytoliths are extensively utilized as an archaeobotanical indicator in paleovegetation reconstruction and environmental archaeology. Over the past two decades, numerous phytolith morphotypes, particularly those exhibiting diagnostic morphological features and over representative of source plants at the genus and species levels, were discovered and reported. These advancements have significantly contributed to phytolith-based vegetation reconstruction on different timescales, enhanced our understanding of prehistoric plant utilization, and elucidated cultivation and domestication processes of key crops in ancient agriculture. However, there are still inconsistencies and misunderstandings regarding the morphological characteristics of diagnostic phytoliths in various plant groups. This review highlighted the standardization in the classification and description of phytolith morphotypes, and summarized the advancements in phytolith morphology research over the past two decades. Morphological illustrations of diagnostic phytoliths from various plant groups, particularly key crops and their relatives from dryland and rice agriculture in East Asia, were presented as references for phytolith identification and application. Finally, this review proposes future directions for phytolith morphological studies, emphasizing the comprehensive consideration of anatomical structure and morphometric parameters, as well as the need for extensive research on modern plant phytoliths and control experiments on phytolith growth.

Optimization of extraction method for quantitative analysis of Si/Al in soil phytoliths

Elemental information carried by phytoliths plays a crucial indicative role in geochemical research.For instance,it serves as an indicator of the carbon pool effect in phytoliths and aids in the elucidation of silicon sources.However,early extraction methods for soil phytoliths primarily focused on obtaining their morphological and quantitative information,lacking efficient techniques for quantitative elemental analysis.In this study,we aimed to extract Si/Al information from soil phytoliths.Considering the need for complete extraction of phytolith,six extraction methods were developed and further by alkaline dissolution to determine Si/Al.Six methods were compared in terms of enrichment capacity,the weight of extracted phytoliths,and Si/Al differences.The results indicated that the addition of Ammonia-Catechol in the commonly used heavy liquid flotation method effectively improved phytolith extraction capability and the accuracy of Si/Al results.Additionally,the inclusion of an acetic acid step before alkaline dissolution further removed surface-adsorbed impurities and enhanced the analytical quality of Si/Al in phytolith.The comparison of the data in this study with other published data shows that our method is relatively robust.The improved method proposed in this study can provide a new idea for the quantitative analysis of other elements in soil phytoliths.

对phytolith汉译名的商榷

基于对ｐｈｙｔｏｌｉｔｈ一词内涵和使用沿革的回顾，笔者主张将其译为植结石，可以与动结石（ｚｏｏｌｉｔｈ）匹对，不主张将其译为“植物硅酸体”、“植物硅石”、“植物硅体细胞”和“植物石”。同样，一门新兴的边缘学科──ｐｈｙｔｏｌｉｔｈｉｃｓ可译为植结石学。

国际植硅体命名法规(International Code for Phytolith Nomenclature 1.0)的介绍与讨论

随着植硅体分析的广泛应用,植硅体命名规范化已经成为趋势。文章对国际植硅体命名法规中植硅体类型划分、命名和描述的方法与术语进行介绍,提供部分中文对应译名,并对该法规中存在的问题进行探讨,以期引起国内学术界的重视,为我国植硅体命名规范化提供参考。

Pollen and Phytolith Analyses of Ancient Paddy Fields at Chuodun Site, the Yangtze River Delta

A number of paddy fields pertaining to the Majiabang Cultures (5500-3800 years BC) were discovered during the archaeological excavations that were carried out since 1998 at the Chuodun site in the Yangtze River Delta. The pollen and phytolith analyses of two soil profiles from the northeastern part of this site were carried out to trace the agricultural practices of the Neolithic period. The phytolith results showed that rice domestication in the Yangtze River Delta could be traced back to as early as the Majiabang Culture. The pollen assemblage also revealed low levels of aquatic species, similar to that in modern paddy fields. This finding suggested that humans might have removed weeds for rice cultivation during the Neolithic period. Thus, pollen analysis in association with phytolith analysis was a promising method for identifying ancient paddy fields.

Paleo-environmental evolution based on high-resolution phytolith since 26 ka B. P. in Huanghe River Delta

The Huanghe River Delta is one of the world＇s large rivers, the Huanghe River Delta paleoenvironmental evolution in the Huanghe River has been a hot issue since the Last Glacial. Based on the core time series established by combining AMS 14C dating of Core DYZK1 sediments in submerged of Huanghe River Delta and acoustic sequence on sub-bottom profile, phytolith analyses are carried out on 96 sediment samples. The grain size parameters, magnetic susceptibility are combined with the vertical changes of biostratum to reconstruct the paleo-sedimentary and climatic conditions in the Huanghe River Delta. The study results show that there is a significant vertical change law in the index parameters, and that sedimentary environment of Huanghe River Delta experienced an evolutionary process of fluvial facies-sealand transition facies-tidal flat facies-neritic facies- delta facies since 26.0 ka B. P.. The phytolith analyses results are as following. Firstly, The phytoliths are divided into lanceolate, smooth-elongated, spiny-elongated, rondel, long rectangular, bulliform and other types. In different sedimental environment, the phytolith content changes regularly, indicating that the phytolith assembles in the same sedimentary environment has a certain degree of stability. Secondly, The lanceolate, smooth-elongated and spiny-elongated categories of phytoliths have greater contents in the tidal flat facies and delta deposition, while have a smaller contents in the neritic facies and fluvial facies environment. Thirdly, Through comparative analysis of variation coefficient, the content of major phytolith categories in the sediment has a greater change amplitude in the sealand transition facies and fluvial facies deposition, while being more stable in the tidalflat facies and delta facies deposition.

Contribution of phytoliths to total biogenic silica volumes in the tropical rivers of Malaysia and associated implications for the marine biogeochemical cycle

The contribution of phytoliths to total biogenic silica(BSi) volumes in rivers worldwide,and the associated implications for the biogeochemical cycle,require in-depth study.Based on samples from rivers in Peninsular Malaysia,this project investigated the source and characteristics of B Si found in Asian tropical rivers,as well as the process of reverse weathering taking place in these fluvial systems.Results indicated that BSi samples collected in sediments consisted of phytolith,diatom and sponge spicules.Phytoliths,predominantly of the elongate form,comprised 92.8%-98.3% of BSi in the Pahang River.Diatom BSi in this river consisted mainly of pennatae diatoms,but represented a relatively small proportion of the total BSi volume.However,diatom BSi(predominantly of the Centricae form) was more prevalent in the Pontian and Endau Rivers with shares of 68.8% and 79.3% of the total BSi volumes,respectively,than Pahang River.Carbon contents of the BSi particulates ranged from 1.85% to 10.8% with an average of 4.79%.These values are higher than those recorded in other studies to date,and indicate that BSi plays a major role in controlling permanent carbon burial.This study suggests that phytoliths from terrestrial plants are the primary constituents of BSi in the rivers of Peninsular Malaysia,and therefore represent a significant proportion of the coastal silica budget.

Responses of Phytolith in Guinea Grass(Leymus chinensis) Leaves to Simulated Warming,Nitrogen Deposition and Elevated CO_2 Concentration in Songnen Grassland,Northeast China

Deposited in plant cells and their intercellular space,phytoliths,a special form of silica,could be used to determine information on plant structure and physiology especially their size and content.With the hypothesis that phytolith in plant would change under variable climate and environment,the dominant plant species in Songnen grassland,guinea grass(Leymus chinensis),was treated by an open-top chamber(OTC) to elevate CO2 concentration,infrared heaters,and artificial nitrogen(N) addition for three years from 2006–2008.Phytoliths were extracted by wet-ashing method and analyzed by variance analysis and so on.We found that the responses to elevated CO2 are complicated,and warming is positive while N addition is negative to the deposition of phytoliths in L.chinensis leaves.Especially,warming could reduce the negative impact of N addition on phytolith in L.chinensis.The short cell's taxonomic in graminea is significant because of no disappearance with simulated environmental changes.The phytolith originated in the long cell and plant intercellular space are more sensitive to elevated CO2 concentration,warming,and N addition,and could become some new indicators for environmental changes.In conclusion,different phytolith types have various responses to simulated warming,N addition and elevated CO2 concentration.

The Need of Time:Phytoliths for Earth Science

Phytoliths take the shape and size of the cells from which they are formed.They are microscopic and composed of opal silica—SiO2 and other traces of Al, Fe,Mn,P,Cu,N and organic carbon.Phytoliths are present in the roots,leaves,stem and the rest parts of the plant body including inflorescences.The shapes of phytolith can be used to determine the taxonomy of the plants,which may be dumbbell,squares,rectangular,

The Phytolith and Pollen Record since 10 ka BP from the Lhasa Region, Tibet

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.

Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths

Mostly fed with grass in fresh or conserved form,cattle and other livestock have to cope with silicate defence bodies from plants(phytoliths)and environmental silicates(grit),which abrade tooth enamel and could additionally interact with various salivary proteins.To detect potential candidates for silicate-binding proteins,bovine whole saliva was incubated with grass-derived phytoliths and silicates.Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed.After intense washing,the powder fractions were loaded onto 1D-polyacrylamide gels,most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates.All materials were mainly bound by bovine odorant-binding protein,bovine salivary protein 30×10^(3) and carbonic anhydrase VI.The phytolith/silicate fraction showed additional stronger interaction with haemoglobinβand lactoperoxidase.Conceivably,the binding of these proteins to the surfaces may contribute to biological processes occurring on them.

Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths

Mostly fed with grass in fresh or conserved form, cattle and other livestock have to cope with silicate defence bodies from plants （phytoliths） and environmental silicates （grit）, which abrade tooth enamel and could additionally interact with various salivary proteins. To detect potential candidates for silicate-binding proteins, bovine whole saliva was incubated with grass-derived phytoliths and silicates. Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed. After intense washing, the powder fractions were loaded onto 1D-polyacrylamide gels, most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates. All materials were mainly botmd by bovine odorant-binding protein, bovine salivary protein 30× 10^3 and carbonic anhydrase VI. The phytolith/silicate fraction showed additional stronger interaction with haemoglobin β and lactoperoxidase. Conceivably, the binding of these proteins to the surfaces may contribute to biological processes occurring on them.

Morphological Characteristics and Environmental Implications of Phytoliths in Topsoils from Different Vegetation Zones on Northern Slope of Changbai Mountains,China

The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.

Phytolith Records in Vermicular Red Earth:Implications for Bioclimatic Variationsduring Pleistocene

Phytolith analysis is employed in bioclimatic research into vermicular red earth, especially into its form, assemblage and zonation. The phytolith assemblage is divided into 10 zones. The statistics and main factor analysis of phytolith show that the obtained main factor load curves could suggest a climate change. Combined with phytolith assemblage feature, the bioclimatic variation of vermicular red earth during its formation stage, consisting of 5 arid-cold stages, 4 warm-humid stages and 2 mild stages, is reconstructed in detail. The research results indicate that phytolith records are ideal paleoclimatic signals in vermicular red earth, and that abundant information on environmental evolution can be located.

Sedimentary Precambrian deposits in southwestern Transbaikalia (Siberia): phytoliths content, lateral correlations and geodynamics

The Baikal Group is one of the most important stratigraphic units in the geology of East Siberia (Upper Riphean). This paper focuses on litological-facies features based on the analysis of organic remains (stromatolites, microphitolites and microfossils), in order to better precise the age and environmental deposit conditions of the Baikal Group. The results are used to draw a correlation between all the Precambrian of deposits of the South of East Siberia. The stratigraphy of the Baikal Group is then compared to the geodynamic evolution of this region, characterized by the break-up of the supercontinent Rodinia and subsequent opening of the Paleo-Asian Ocean. Stratigraphic analogs to the Baikal Group display in most areas deposits of various minerals (complex ores, phosphoresces, bauxites etc. have been dated of the same age), so the present study would also provides an economic interest.

Effects of Silicon Fertilization on Soil Chemical Properties and Phytolith Formation of Phyllostachys pubescens

Silicon is benefit to Gramineae plants in growth and resistance to various stresses.However,the effect of silicon fertilizer application on Phyllostachys pubescens is still not investigated yet.Phyllostachys pubescens Mazel ex J.Houz is one kind of Gramineae plants which distributes in a large area.In this study,a field experiment with five Si fertilizer application rates(0,125,250,375,and 500 kg ha-1)was setup in a Phyllostachys pubescens forest in China to examine the effects of Si fertilizer on bamboo Si and phytolith accumulation in fresh leaf and leaf litter.Results showed that Si application increased soil available Si content in deep layers.Si content of leaf-litter increased with the increasing level of Si fertilizer application rate,with the value ranging from 114.3 g kg^(−1)to 172.7 g kg^(−1),however,no significant difference was observed in fresh leaf,with the value ranging from 84.0 g kg^(−1)to 115.0 g kg^(−1).The phytolith contents of leaf-litter and fresh leaf were consistent with the Si contents,the phytolith content in leaf-litter of T4(500 kg ha^(−1))was 48.4%higher than the control,suggesting Phyllostachys pubescens exhibited an increasing carbon sink in phytolith when Si fertilizer applied,which is an effective way to increase long-term soil organic carbon storage in Phyllostachys pubescens forests with a suitable Si fertilization.

The phytolith carbon sequestration in terrestrial ecosystems:the underestimated potential of bamboo forest

Background Terrestrial ecosystems contain significant carbon storage,vital to the global carbon cycle and climate change.Alterations in human production activities and environmental factors affect the stability of carbon storage in soil.Carbon sequestration in plant phytoliths offers a sustainable method for long-term carbon stabilization.Carbon occluded in phytoliths(PhytOC)is a kind of carbon that can be stable and not decomposed for a long time,so it is crucial to conduct more in-depth research on it.Results We undertook a meta-analysis on PhytOC across global terrestrial ecosystems,analyzing 60 articles,encapsulating 534 observations.We observed notable differences in phytolith and PhytOC contents across various ecosystems.Bamboo forest ecosystems exhibited the highest vegetation phytolith and PhytOC content,while soil phytolith content was most prominent in bamboo forests and PhytOC content in croplands.Human activities,such as grassland grazing,had a lesser impact on soil PhytOC transport than actions like cutting and tillage in croplands and forests.Our study separated bamboo ecosystems,analyzing their PhytOC content and revealing an underestimation of their carbon sink capacity.Conclusions Notwithstanding our findings,phytoliths’intricate environmental interactions warrant further exploration,crucial for refining ecosystem management and accurately estimating PhytOC stocks.This deepened understanding lays the foundation for studying phytoliths and the carbon sink dynamics.

Rice use history in Southeast China:Phytolith evidence from the Nanshan site in Fujian Province

The southern spread of rice agriculture is of great academic interest.Although it already has a broad chronological framework,newly introduced rice use and its impact on local subsistence and ecological systems are still unclear.In this study,we explore these issues by analysing phytoliths recovered from continuous sediments of Cave No.4 at the Nanshan site in Fujian Province,together with evidence from surrounding sites.The results show that rice was introduced into southeast China at 7,500 cal.yr BP,but the dominance of the hunting-gathering system was not challenged until later,between 5,000 and 3,500 cal.yr BP,when cultivation of rice,together with foxtail and broomcorn millets,was widely practiced in the region.This suggests that mixed farming in Southeast China,likely originating around the middle Yangtze River,became widespread and gradually systematic during the previous two-millennium adoption.This rice-millet mixed agricultural system changed the former hunting-gathering subsistence system,promoting the agriculturalization process,cultural prosperity and population growth,thus providing a solid basis for rice expansion and cultural migration to Southeast Asia.

福建琅岐岛表土孢粉与植硅体组合对农业活动的指示

孢粉和植硅体是重建古人类农业景观及环境变化的重要指标,明确它们在表土中的分布规律及其与现代植被组成之间的关系对于精确解释化石孢粉和植硅体数据具有重要的意义。本研究对福建琅岐岛3种土地利用类型的22个表土样品进行了孢粉与植硅体分析,基于地理信息系统和遥感技术,展示了不同类型孢粉百分比的空间分布及其与植被覆盖度间的数量对应关系。孢粉分析表明,以松属(Pinus)为代表的外来花粉普遍存在于表土样品中,这削弱了采样点周围植物的孢粉表现力,导致了果园和农田植被组成与表土孢粉组合间的巨大差异。与此同时,农业收割活动进一步降低了农田植物的花粉表现力。从遥感影像中提取的植被覆盖度数据仅与荒地上的木本植物花粉含量存在较强的相关性(R^(2)=0.7764),这显示茂密的草本植物降低了外来木本花粉的相对含量,证明了该植被类型具有良好的孢粉表现力。植硅体分析表明,表土样品含有丰富的竹亚科(Bambusoideae)、水稻(Oryza sativa)和杂草的植硅体。与孢粉指标相比,植硅体提供了更丰富的草本植物信息。

广西崇左江西岸遗址人类的生存方式

极端气候环境事件及其引起的早期人类经济模式转变是过去全球变化领域的热点问题,然而,目前针对9200 BP气候事件对史前人类行为方式的影响一直缺乏研究。广西是珠江流域的重要区域之一,具有独特的植被、气候和环境背景,既是史前人群迁徙和文化交流的重点地区,也是应对气候突变和气候事件的理想避难所,是人类生存方式和环境适应研究的难得实验场。本文基于AMS 14C年代学以及植硅体与孢粉等微体遗存记录,对广西崇左江西岸遗址新石器时代文化的气候环境背景与生业经济模式进行分析。研究表明,广西江西岸遗址新石器时代地层的年代为9300-9100 BP;在9200 BP气候事件中,该遗址周边环境呈现明显的冷干化趋势;该阶段人类可选择的植物资源较少,而地层中则发现了大量的螺壳、蚌壳和水牛、犀牛、象等水生动物与哺乳动物遗骸以及渔猎工具。上述结果表明,广西江西岸遗址的气候在9200 BP时处于冷干期,导致可采集的植物资源减少,因此,江西岸遗址的人类可能选择渔猎方式适应生存。这一研究为深入理解亚洲季风区早全新世重要气候事件与新石器时代文化发展之间的相互作用关系提供了新的思路和线索。