Root Traces Research Articles

An advanced species of the fern Botryopteris Renault from the Permian of southwestern China

We describe a new species of the Paleozoic fern genus Botryopteris in volcanic tuffs from the Lopingian (upper Permian) aged Junlian Formation in SW China's Sichuan Province. The species has a large stem and stele compared to those of some other species of the genus. Xylem strands of the leaf trace and rachis are “ω”-shaped in cross section and comprise two long lateral arms and a single, shorter median arm. Parenchyma is distributed among the stem metaxylem tracheids and is more common in the central region of the stele that comprises a parenchymatized protostele. Several mesarch protoxylem strands, decurrent from leaf traces, are visible in each cross section of the protostele. Root traces originate from the lateral side of the leaf trace within the stem cortex. The stem surface is covered by thick, multiseriate, multicellular trichomes. Botryopteris multifolia sp. nov. represents the stratigraphically youngest known species of the genus and has a combination of derived evolutionary characteristics including its large stem size, parenchymatized protostele, elaborate trichome structure, roots originating from leaf traces, and the construction of xylem strand of the leaf trace and rachis with distinctive pinna trace formation and emission. It is more similar in leaf anatomy to the Gondwanan species B. nollii from the Permian of Brazil and less like late Pennsylvanian botryopterids from Euramerica. Finally, we consider the evolutionary implications of features shared between Permian members of the botryopterids and catenalean-type plants including members of the Osmundales stem group family Guaireaceae (Shuichengella, Zhongmingella, Tiania) and the enigmatic early ferns Rastropteris and Catenopteris.

Clay Minerals and Micromorphology of the Loess Paleosols, Kashmir Valley, India

Loess paleosols have been often studied to reconstruct late Quaternary past climate changes. In the present study, textural analysis, TOC, CaCO3 content, micromorphology and clay mineralogy of the three loess paleosol profiles from three sites (Choori, Alochibagh and Burzahama), from Kashmir valley are presented. Based on the dates of Burzahama section, the exposed loess paleosols are approximately dated to 45ka. Textural analyses suggest that the sediments are largely fine silt followed by silty loam and silty clay loam. The fine sand component in the loess and paleosols indicate that winds in the valley were strong, but in phases the wind velocity was low. The paleosols are much thicker than loess layers and form several horizons within the lithosections. The increase of CaCO3 content indicates that it has leached in phases and along with total organic carbon (TOC) resulted in mild pedogenesis with variations in the rate of pedogenesis within the paleosols and forming pedocomplexes. Micromorphology of the loess-paleosols indicates the presence of calcite nodules with iron oxide coating indicating sub-aerial weathering and pedogenesis. The presence of channel structures in loess paleosols formed due to root traces and pores probably during the warmer periods. The replacement of chlorite by smectite clays in loess paleosols suggests that the alteration of clay minerals probably took place in cold, dry, warmer climatic conditions in low wind regime.

Three-dimensional structure of stem vascular connections with leaf and adventitious root in Asplundia brachypus (Drude) Harling (Cyclanthaceae)

The monocotyledonous vascular system is complex in arrangement, and its anatomical study is relevant to understand sap conduction in the group and elucidate stelar terminological issues. This work aimed to characterize the three-dimensional structure of the stem vascular connections with the leaf and adventitious root in Asplundia brachypus (Drude) Harling (Cyclanthaceae). Three internodes from different individuals were serially cross-sectioned for the preparation, photomicrography and description of anatomical slides. Three-dimensional representations of leaf and root trace courses were produced using R software. Leaf and root traces are simple collateral bundles with tracheary elements of small diameter. Acropetally, leaf traces show a centrifugal course along the internode and tangentially incline at the nodal level. At the adventitious root level, root traces arrange in a root vascular plexus extending up- and downward, longitudinally delimited by parenchyma. The small diameter of tracheary elements in leaf and root traces, the course extension of leaf traces and the longitudinal discontinuity of root traces with axial vascular bundles indicate conductive safety at the stem vascular connections with the leaf and adventitious root in A. brachypus. The three-dimensional vascular arrangement in the stem was demonstrated using an alternative methodology in representing bundle courses, evidencing the misleading nature of the terms "atactostele" and "placostele", alternatively described as a monocot cyclostele.

Paleosols and host rocks from the Middle–Upper Permian reference section of the Kazan Volga region, Russia: A case study

The Urzhumian (Wordian) and Severodvinian (Capitanian) reference section of the Monastery Ravine (Kazan Volga region, Russia), contains two siltstone lithofacies: (a) laminated and (b) massive. Depositional settings of the laminated siltstones can be interpreted as perennial to ephemeral lakes; depositional settings of the massive siltstones are interpreted as floodplains with soil cover and periodical silt influx in wet seasons. The bulk geochemistry of siliciclastics has revealed a high degree of weathering of both types of siltstone. The similar chemical composition, mineralogy, and grain size suggest the same provenance of silt material. Geochemical data indicate eastern source rocks, which are the Permian red beds of the Cis-Ural plains.The main genetic types of paleosols hosted in the massive siltstones in the studied section, include moderately developed Vertisols and Calcisols with drab-colored root traces, calcareous nodules, low chroma mottles, angular blocky peds and slickensides. These pedofeatures indicate in general a semi-arid climate with clear seasonality of rainfall. Major oxides of the paleosol matrix were used to estimate paleoprecipitation through the bases to alumina (ΣBases/Al) ratio and chemical index of alteration minus potassium (CIA-K) proxies. Estimates from Urzhumian paleosols indicate relatively low mean annual precipitation (MAP) of 390mm/yr. The transition to the Severodvinian paleosols is marked by a noticeable MAP increase up to 777mm/yr. This climate moistening coincides with changes in the morphology of paleosols from dolomitic with low redoximorphy to calcitic with gley horizons. The pedogenic carbonate nodules consisting of dolomicrite (5–10μm) are very common in the Urzhumian paleosols and their morphology, micromorhology and isotopic features indicate the pedogenic origin of dolomite.Sedimentological and paleopedological features of the studied siltstones, as well as the location of the Volga-Ural basin in a mid-latitude position (25–32°N) indicate a monsoonal character of precipitation during the Middle Permian.

From Vertical to Dynamic Transfer: Recognizing Continuous Swirl in American Higher Education

In recent years, transfer and articulation has become a hot topic within the higher education research and policy literature. This is evidenced by the myriad of terms whose roots trace to the broad...

Late glacial and Holocene sand drift in northern Götaland and Värmland, Sweden: sediments and ages

ABSTRACTThe aeolian deposits of Sweden have received modest attention, despite their usefulness as a palaeoenvironmental archive. Here we present sedimentological information and optically stimulated luminescence (OSL) ages from inland sand dunes in the lowlands of south-central Sweden. Three main lithofacies, each with two subfacies, were identified in the deposits: massive sand, laminated sand and cross-bedded sand. Massive sand was most common and present at all sites, and is largely due to secondary bioturbation when found close to the surface. Other prevalent depositional processes are wind-ripple migration and grain flow. Secondary features include animal burrows and tracks, root traces, infiltration structures and soil profiles. The luminescence ages plot in two different groups, centred in the early and late Holocene, respectively. The primary dune-forming phase occurred in the early Holocene, after local deglaciation and uplift above sea/lake level. However, at some sites, OSL ages suggest a prolonged phase of sand drift, or repeated reworking, long after deglaciation due to locally beneficial conditions. The late Holocene was dominated by reactivation events and sheet sand deposition, which led to the formation of an aeolian mantle.

Petrography, micromorphology and geochemistry of Mio-Pleistocene palustrine limestones in Kuwait, Arabian Gulf

Elongated lenses of palustrine limestone interbedded with Mio-Pleistocene fluvial sands were exposed within a sand quarry in the north of Kuwait. Detailed field investigations, thorough petrographic and nanoscopic examinations and geochemical analysis revealed that they were originally precipitated as carbonate microbialite in isolated freshwater ponds scattered within a fluvial floodplain. These lacustrine microbialites were subjected to intermittent drying and wetting conditions and eventually altered to pseudobrecciated nodular palustrine limestone through several pedogenic and early diagenetic processes. The pedogenesis is exhibited by cracking, nodulization, mottling, pseudomicrokarst and root traces. The desiccation macrocracks are filled with siliciclastic sands derived from short-lived flash floods. Diagenesis is represented by aggradational neomorphism of micrite, cementation of cracks and voids by sparry calcite and precipitation of biogenic needle-fibre calcite. Concurrently, the cracks filled with siliciclastic sands have been calcretized, forming an embedded interapalustrine calcrete. Mottling postdates the early diagenesis and is manifested by pseudoclotted texture and abundant black spots and dendrites, which may have been developed by the marmorization of iron and manganese ions due to the seasonal fluctuation of groundwater. The δ13C and δ18O values are mostly comparable with those of closed freshwater lakes; however, the high negative values of δ18O may be attributed to diagenetic calcite. The occurrence of this palustrine limestone within a fluvial siliciclastic sequence that lacks clearly developed calcrete profiles may present an exceptional setting for palustrine limestone.

Distribution and chemical forms of cadmium in Coptis chinensis Franch. determined by laser ablation ICP-MS, cell fractionation, and sequential extraction

Coptis chinensis Franch., is a widely used medicinal plant in China. This plant is often contaminated by cadmium (Cd) and render health risk to human consumers. Understanding distribution of Cd and its chemical forms is important to evaluate accumulation of the metal and its detoxification mechanisms in this plant. Since few studies have focused on this aspect, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to spatially locate Cd in rhizome cross-sections, and ICP-MS to analyze the Cd subcellular distribution and the chemical forms of Cd in different tissues. Rhizome bioimaging results showed that Cd was distributed predominantly within the periderm, cortex, pith, and root trace vascular bundle. The LA-ICP-MS results suggested that Ca2+ channels might be a pathway for Cd entry into the plant. Subcellular distribution data indicated that most of Cd was associated with the cell wall (41.8–77.1%) and the soluble fraction (14.4–52.7%) in all tissues. Analysis of chemical forms revealed that majority Cd existed in less mobile and less toxic forms in all tissues, and P could convert to insoluble phosphate with Cd to moderate Cd toxicity. The new understanding of Cd accumulation and detoxification might provide novel strategies for reducing the levels of Cd in C. chinensis Franch., thereby mitigating its potential transfer to humans and providing a theoretical basis for evaluating the Cd status in other medicinal plants. Further, our findings might provide a basis for establishing a reasonable Cd limit level of traditional Chinese medicinal materials.

Effect of pedogenesis on the stable isotopic composition of calcretes and n‐alkanes: Implications for palaeoenvironmental reconstruction

AbstractIn a fluvial system, depending on sub‐aerial exposure, non‐pedogenic pond calcretes can be modified into pedogenic calcretes. The present study attempts to understand the effect of sub‐aerial exposure and pedogenesis on calcretes using carbon and oxygen isotopic composition. For this purpose, two profiles (profile‐A and profile‐B) from the same stratigraphic level in Rayka from the western part of India were selected. The profiles are separated by a distance of 500 m and showed differences in calcrete characteristics. In profile‐A, the calcretes showed pedogenic features (root traces and void filling spar) whereas calcretes in profile‐B showed non‐pedogenic characteristics (fine laminations). However, some of the calcretes in profile‐A exhibited remnants of fine laminations suggesting that initially the calcretes had a non‐pedogenic origin but were modified due to pedogenesis. In profile‐A, the carbon and oxygen isotope values of pedogenic calcrete (δ13CPC and δ18OPC) showed more variation compared with non‐pedogenic pond calcretes (δ13CSPC and δ18OSPC) in profile‐B. The δ13CPC and δ13CSPC values exhibited a spread of 3·0‰ and 1·3‰, respectively, and δ18OPC and δ18OSPC values showed a spread of 2·3‰ and 1·3‰, respectively. The differences in the isotopic composition between the two profiles suggest that pedogenesis controlled the isotopic inheritance in calcretes. In addition, the carbon isotopic composition of organic matter (δ13COM) and n‐alkanes (δ13Cn‐alk) that forms the basis of palaeovegetational reconstruction have also been measured to understand the effect of pedogenesis on organic matter in both of the profiles. The average δ13COM values in profile‐A and profile‐B are −23·4‰ and −21·1‰, respectively. The disparity in δ13COM values is a result of the difference in the sources and preservation of organic matter. However, the δ13Cn‐alk values show a similar trend in profile‐A and profile‐B, indicating that sources of n‐alkanes are the same in both of the profiles and δ13Cn‐alk values are unaffected by the pedogenic modifications.

Paleosols in Devonian red-beds from northwest China and their paleoclimatic characteristics

Paleosols have been discovered in the late Devonian (Famennian) Shaliushui Formation near Pingchuan City, Gansu province, China, and are recognized by evidence of root traces, soil horizons and soil structures. Root traces are remnants of substantial woody plants, reaching deeply within profiles as clayey infills and as drab-haloed root traces. Soil horizons include thick layers of large calcareous nodules (Bk horizon), and subsurface accumulations of clay (Bt horizon), and slickensided claystone (vertic Bw horizon). Soil structures include blocky peds and calcareous nodules. The nodules and drab-haloed root traces formed syndepostionally during the late Devonian, because they were also observed in clasts of paleosol and nodules in fluvial conglomerates interbedded with the paleosols. Analyses for Rb/Sr and Ba/Sr ratios and magnetic susceptibility measurements confirm that the more strongly developed paleosols with larger calcareous nodules and higher clay content are also more chemically differentiated and have higher magnetic susceptibility under semi-arid climates. This suite of paleosols is evidence of semi-arid to sub-humid, highly seasonal climate under dry woodlands and shrublands. Paleosols of the Shaliushui Formation are a potentially valuable archive of late Devonian palaeoclimates of northwest China.

Interflag sandstone laminae, a novel sedimentary structure, with implications for Ediacaran paleoenvironments

Interflag sandstone laminae are thin, silty to sandy, layers between thicker sandstone beds, and a new name for sedimentary structures recently called “shims”, and “microbial mat sandwiches”, from Ediacaran fossil localities of Nilpena, South Australia. They have been regarded as structures unique to Precambrian marine environments, but both the age and environmental associations are reinterpreted in this study. Interflag sandstone laminae from Eocene (Wasatch Formation, Colorado, U.S.A.) and Pennsylvanian (Mansfield Formation, Indiana, U.S.A.) fluvial levees and scroll bars were studied in the field, and by means of petrographic thin sections and granulometry. Climbing translatent ripples and distinct grain size distributions are evidence that interflag sandstone laminae were eolian, whereas intervening flagstones were deposited by fluvial traction currents. Other evidences of exposure to wind include microbial earth textures, shallow cracking structures, zibars, setulfs, root traces, and insect trackways. Other evidences of flagstone deposition in traction currents include intraformational claystone breccias, oscillation and current ripples, and microbial mat textures. Similarly distinct beds can be seen in modern sandy river levees, such as the Murchison River of Western Australia and Green River of Utah (U.S.A.). These observations reveal that interflag laminae are created by exposure and wind-drift, but flagstones are produced by floods. Quartzose flagstones of demonstrable marine origin, with fossil brachiopods and trilobites, have also been examined, but lack interflag sandstone laminae. Interflag sandstone laminae are evidence of alternating flood and wind, only known from fluvial environments, and are further support for the idea that Ediacaran vendobionts from South and central Australia, and Namibia lived on land.

Ichnology and sedimentology of the trace fossil-bearing fluvial red beds from the lowermost member of the Paleocene Funing Formation in the Jinhu Depression, Subei Basin, East China

Abstract The lowermost member of the Paleocene Funing Formation, which is composed of bioturbated fluvial red beds, is extensively distributed throughout the Jinhu Depression, Subei Basin, East China. Despite its economic value as one of the most important oil-bearing reservoirs in the Subei Basin, the sedimentology, ichnology and paleoenvironment of this formation in the Jinhu Depression remain poorly understood. In this work, we investigated the ichnofossils and sedimentary facies, analyzed the ichnofacies and potential tracemakers and reconstructed the paleoenvironment of the Jinhu Depression based on cores from the lowermost member of the Paleocene Funing Formation. This formation contains a moderately diverse ichnofauna (9 ichnotaxa of the Scoyenia ichnofacies) that includes meniscate burrows (Taenidium barretti, Taenidium satanassi and Beaconites coronus), simple horizontal cylindrical burrows (Palaeophycus tubularis, Palaeophycus heberti and Planolites isp.), simple vertical or subvertical burrows (Skolithos linearis and Skolithos isp.) and plant root traces. The other complex branched and chambered burrows are left in open nomenclature. These ichnofossils are widespread throughout the three facies associations identified in this study: (1) ephemeral fluvial channel, (2) crevasse splay and (3) distal floodplain facies associations. Multiple lines of sedimentological and ichnological evidence, namely, the predominance of massive and upper flow regime structures, the occurrence of invertebrate burrows (e.g., Skolithos and Taenidium) in the lower and middle parts of the channel deposits and the dramatic changes in the color and mottling in channel and overbank sediments, indicate that the river discharge was short lived and that the water table was highly variable. The variations in the discharge and water level are attributed to the influence of seasonal rainfall. The cyclic nature of intense rainfall events and dry periods suggests that the Subei Basin was likely located in a semiarid region with a seasonal rainfall pattern during the early Paleocene. This study also reveals that the ephemeral fluvial channel is the facies association with the highest potential to yield oil-bearing reservoirs in the Paleocene red beds of the Jinhu Depression. Additionally, the influence of bioturbation on the reservoir quality in this region should be considered in future research.

Ectomycorrhiza Status of Castanopsis buruana Miq. in The Field

Castanopsis buruana Miq. is one of the important species, growing in Indonesian lowland forest. The plant is used as source of wood and highly nutritious nuts. Castanopsis is reported to be associated with ectomycorrhiza, although the C. buruana Miq. which grows in Indonesian tropical rain forest has not been known for its ectomycorrhiza status. The objective of this research was to study the ectomycorrhiza status of C. buruana Miq. which grows in Sulawesi forest as endemic species. Samples were collected from C. buruana Miq. in Grand Forest Park Nipa-Nipa, Kendari. Collection of samples in the field was conducted with line transect technique using root tracing method. Ectomycorrhiza morphotype, root anatomy and root colonization analyses used method of Colour Atlas of Ectomycorrhizae, microtome and gridline intersection, respectively. Analysis results showed that roots of C. buruana Miq. formed eight different root tip morphotypes. Percentage of ectomycorrhiza colonization of the eight morphotypes varied and were categorized into 3 groups, namely <5%, 5-10% and > 50%. Unramified black root tip morphotype exhibites the highest colonization percentage (53,76%) compared to the others root tip morphotype observed.

The paleoecological and paleoenvironmental importance of root traces: Plant distribution and topographic significance of root patterns in Upper Cretaceous paleosols

Rhizoliths are organosedimentary structures produced by plants and are an important proxy for paleoenvironmental reconstructions because the differences in the morphology of rhizoliths and their rooting depths can be used to interpret soil humidity regimes, overall biomass at the soil surface, and the behavior of the water table. With the objective of advancing knowledge on rhizoliths, a study was performed on the macromorphological and micromorphological characterizations of the rhizoliths preserved in the thirty-one paleosols of the Marília Formation in Minas Gerais, southeastern Brazil. Based on the topological and architectural attributes of rhizoliths, and on their possible functional adaptations, such as mycorrhizal associations, three different types of rhizoliths are described in this study and represent at least three different plants: rhizohaloes, root casts and rhizocretions. Well-developed paleosols with nodular horizons contain the higher density of long root casts, indicating a seasonally dry environment, because the root casts present two meters in length. These adaptations are associated with an exploitation of a lowered water table during most times of the year. The higher density of rhizoliths indicates an area with agglomerated arboreous arbustive vegetation cover. Paleosols with chalky horizons also show a high density of root casts, indicating a landscape with high plant density that is adapted to drained soils, but with a seasonally elevated water table or the influence of ephemeral flows, given the proximity to the flow channels. The poorly drained paleosols with redoximorphic features show the lowest density of rhizoliths, thus indicating an incipient vegetation in response to near-surface water table and waterlogged soils in a distal floodplain. The rhizogenic laminar horizons have developed near fluvial channels with frequent sedimentary input, resulting in a sequence of laminar horizons composed of rhizocretions that are separated by sandy deposits or poorly developed pedogenic horizons. The micromorphological analysis on the rhizogenic laminar calcretes showed biogenic features, such as alveolar septal structures, calcified filaments, microcodium, calcified cells and pisoliths. Despite the scarce paleobotanical findings in the Marília Formation, the results obtained indicate an ecosystem that was composed of plants varying from herbaceous to arboreous, with an environment similar to modern semiarid shrublands.

Pleurorhizoxylon yixingensegen. et sp. nov., a Euphyllophyte Axis with Anatomically Preserved Adventitious Roots from the Late Devonian of South China

Premise of research. Rooting structures were major contributors to Devonian global change, but anatomically preserved plant roots are rare from this period. We report a new type of plant axis from the Upper Devonian strata of South China that contains a protostele, relatively extensive secondary xylem, and adventitious root traces.Methodology. The original specimens were fragmentary coalified axes, most of which were embedded in Epon resin, sectioned transversely and longitudinally, and ground into thin sections. The sections were observed and imaged with a light microscope. A few were observed directly with a scanning electron microscope.Pivotal results. The axis of this new plant, named Pleurorhizoxylon gen. nov., consists of a three-ribbed protostele and thick secondary xylem; the primary xylem is of apparent mesarch maturation, with a single protoxylem lacuna near the end of each rib. The secondary xylem has variable rays composed of parenchyma cells and has scalariform to elliptical bordered pits on both radial and tangential walls of the tracheids. The adventitious root traces are located opposite each primary xylem rib going through the wood; they are accompanied by large rays and cause significant accommodation (knotting) in the wood. Extraxylary portions are poorly preserved, and no cambium or secondary phloem has been found.Conclusions. The new plant has a unique combination of characters and demonstrates the anatomical basis for adventitious root growth present in a Devonian moniliform plant, other than cladoxylopsids, for the first time.

Propagation in the Open Cylindrical Guide of Arbitrary Cross Section With the Use of Field Matching Method

A simple solution to propagation problem in open waveguides and dielectric fibers of arbitrary convex cross section is presented. The idea of the analysis is based on the direct field matching technique involving the usage of the field projection at the boundary on a fixed set of orthogonal basis functions. A complex root tracing algorithm is utilized to find the propagation coefficients of the investigated guides. Different convex shapes of the guides are analyzed, and the obtained results are compared with the alternative solutions to verify the validity of the proposed method.

Sedimentology, ichnology, and sequence stratigraphy of the Miocene Oficina Formation, Junín and Boyacá areas, Orinoco Oil Belt, Eastern Venezuela Basin

Abstract The Miocene Oficina Formation is widely distributed in the subsurface of the Orinoco Oil Belt of eastern Venezuela. Despite its economic importance as one of the most important hydrocarbon reservoirs worldwide, little is known about its sedimentologic, ichnologic and sequence-stratigraphic aspects. Sedimentary facies, trace fossils, depositional environments, stratal stacking patterns and surfaces of sequence-stratigraphic significance have been analyzed in the Junin and Boyaca areas. The Oficina Formation is subdivided here into three informal members: lower, middle, and upper. The lower member consists mainly of lowstand fluvial braided-channel deposits filling an incised valley. No evidence of marine conditions is present and the only biogenic structures detected are root trace fossils present at the top of a few fining- and thinning-upward channelized units. The middle member is much more heterogeneous, both vertically and laterally, comprising high-sinuosity estuarine-channel, tidal-flat, tidal-creek and tidal-sandbar deposits, stacked to form a retrogradational package and representing the transgressive systems tract. The middle member is characterized by widespread evidence of tidal influence (e.g. inclined heterolithic stratification) and by the presence of the impoverished Cruziana Ichnofacies and the Skolithos Ichnofacies, both reflecting brackish-water conditions. This member is thought to represent deposition in an estuarine system. The upper member consists predominantly of highstand delta-plain deposits, stacked forming a progradational pattern. These deposits locally show intense bioturbation with a predominance of continental trace fossils, illustrating the Scoyenia Ichnofacies. Deltaic deposits display a mixed influence of tides and river processes. Previous studies invariably assumed a deltaic model for the whole Oficina Formation. However, integration of sedimentologic, ichnologic, and sequence-stratigraphic datasets suggests a more complex depositional evolution, comprising a fluvio-estuarine valley incised during a relative sea-level fall that became filled during the lowstand and subsequent transgression, culminating with deltaic progradation during the highstand.

A new method for the rapid characterization of root growth and distribution using digital image correlation.

Rapidly determining root growth patterns is biologically important and technically challenging. Current methods focus on direct observation of roots and require destructive excavations or time-consuming root tracing. We developed a novel methodology based on analyzing soil particle displacement, rather than direct observation of roots. This inferred root growth method uses digital image correlation (DIC) analysis, an established and high-throughput method used in many engineering and science disciplines. By applying DIC analyses to repeated images of plants grown in clear window boxes, we produced visually intuitive and quantifiable strain maps, indicating the magnitude and direction of soil movement. From this, we could infer root growth and rapidly quantify root system metrics. Strain measures were closely associated with the spatial distribution of roots and correlated with root length measured using conventional approaches. The method also allowed for the detection of root proliferation in nutrient-enriched soil patches, indicating its suitability for quantifying biological patterns. This novel application of DIC in root biology is effective, scalable, low cost, flexible and complementary to existing technologies. This method offers a new tool for answering questions in plant biology and will be particularly useful in studies involving temporal dynamics of root processes.

Root Gravitropism: Quantification, Challenges, and Solutions.

Better understanding of root traits such as root angle and root gravitropism will be crucial for development of crops with improved resource use efficiency. This chapter describes a high-throughput, automated image analysis method to trace Arabidopsis (Arabidopsis thaliana) seedling roots grown on agar plates. The method combines a "particle-filtering algorithm with a graph-based method" to trace the center line of a root and can be adopted for the analysis of several root parameters such as length, curvature, and stimulus from original root traces.

The Early Miocene Critical Zone at Karungu, Western Kenya: An Equatorial, Open Habitat with Few Primate Remains

Early Miocene outcrops near Karungu, Western Kenya, preserve a range of fluvio-lacustrine, lowland landscapes that contain abundant fossils of terrestrial and aquatic vertebrates. Primates are notably rare among these remains, although nearby early Miocene strata on Rusinga Island contain a rich assemblage of fossilized catarrhines and strepsirrhines. To explore possible environmental controls on the occurrence of early Miocene primates, we performed a deep-time Critical Zone (DTCZ) reconstruction focused on floodplain paleosols at the Ngira locality in Karungu. We specifically focused on a single stratigraphic unit (NG15), which preserves moderately developed paleosols that contain a microvertebrate fossil assemblage. Although similarities between deposits at Karungu and Rusinga Island are commonly assumed, physical sedimentary processes, vegetative cover, soil hydrology, and some aspects of climate state are notably different between the two areas. Estimates of paleoclimate parameters using paleosol B horizon elemental chemistry and morphologic properties are consistent with seasonal, dry subhumid conditions, occasional waterlogging, and herbaceous vegetation. The reconstructed small mammal community indicates periodic waterlogging and open-canopy conditions. Based on the presence of herbaceous root traces, abundant microcharcoal, and pedogenic carbonates with high stable carbon isotope ratios, we interpret NG15 to have formed under a warm, seasonally dry, open riparian woodland to wooded grassland, in which at least a subset of the vegetation was likely C4 biomass. Our results, coupled with previous paleoenvironmental interpretations for deposits on Rusinga Island, demonstrate that there was considerable environmental heterogeneity ranging from open to closed habitats in the early Miocene. We hypothesize that the relative paucity of primates at Karungu was driven by their environmental preference for locally abundant closed canopy vegetation, which was likely absent at Karungu, at least during the NG15 interval if not also earlier and later intervals that have not yet been studied in as much detail.