Structure and composition of calcified roots, and their identification in calcareous soils

Jaillard, Benoît; Guyon, André; Maurin, A.

doi:10.1016/0016-7061(91)90034-q

Cited by 119 publications

(68 citation statements)

References 8 publications

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“…Although it is not as strictly related to rhizosphere processes as the example illustrated by 'The Pinnacles', Jaillard (1982Jaillard ( , 1983Jaillard ( , 1984Jaillard ( , 1985 and Jaillard et al (1991) have described another fascinating case of biogenic precipitation of calcite induced by root activity, leading to the formation of calcified roots in calcareous soils. These calcified roots, when fully preserved in the soil, occur and appear as calcite crystals shaping the root cortex cells, while the stele remains free of precipitates (Fig.…”

Section: Root-induced Physical Breakdown Of Rocks and Consequences Fomentioning

confidence: 95%

Plant-microbe-soil interactions in the rhizosphere: an evolutionary perspective

et al. 2009

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Soils are the product of the activities of plants, which supply organic matter and play a pivotal role in weathering rocks and minerals. Many plant species have a distinct ecological amplitude that shows restriction to specific soil types. In the numerous interactions between plants and soil, microorganisms also play a key role. Here we review the existing literature on interactions between plants, microorganisms and soils, and include considerations of evolutionary time scales, where possible. Some of these interactions involve intricate systems of communication, which in the case of symbioses such as the arbuscular mycorrhizal symbiosis are several hundreds of millions years old; others involve the release of exudates from roots, and other products of rhizodeposition that are used as substrates for soil microorganisms. The possible reasons for the survival value of this loss of carbon over tens or hundreds of millions of years of evolution of higher plants are discussed, taking a cost-benefit approach. Coevolution of plants and rhizosphere microorganisms is discussed, in the light of known ecological interactions between various partners in terrestrial ecosystems. Finally, the role of higher plants, especially deep-rooted plants and associated microorganisms in the weathering of rocks and minerals, ultimately contributing to pedogenesis, is addressed. We show that rhizosphere processes in the long run are central to biogeochemical cycles, soil formation and Earth history. Major anticipated discoveries will enhance our basic understanding and allow applications of new knowledge to deal with nutrient deficiencies, pests and diseases, and the challenges of increasing global food production and agroecosystem productivity in an environmentally responsible manner.

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Section: Root-induced Physical Breakdown Of Rocks and Consequences Fomentioning

confidence: 95%

Plant-microbe-soil interactions in the rhizosphere: an evolutionary perspective

et al. 2009

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“…Alveolar septal structures attributed to the calcification of root structures, in association with fungi (Wright 1986), are very common, along with calcified root cells, such as those described by Jaillard et al (1991) and Kosir (2004). NFC coated with microrods is commonly found in modern and recent carbonate soils (Verrecchia and Verrecchia 1994), which is indicative of either direct fungal biomineralization (MA rods) or of physicochemical mineralization of decayed fungal-sheath organic matter (Verrecchia and Verrecchia 1994;Bajnóczi and Kovács-Kis 2006).…”

Section: Calcretesmentioning

confidence: 99%

Root Calcretes and Uranium-Bearing Silcretes At Sedimentary Discontinuities In the Miocene of the Madrid Basin (Toledo, Spain)

Bustillo

Plet

Alonso-Zarza

2014

Journal of Sedimentary Research

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This paper reports a detailed study of the calcrete and silcrete profiles in the Miocene detrital deposits in the western area of Madrid, at the boundary of two main sedimentary units. The aims of this work were to better understand the pedogenic and diagenetic environments in which these profiles formed and to determine the cause(s) of their enrichment in uranium. Calcrete and silcrete duricrusts are characteristic features of closed continental basins in semiarid climates; this paper discusses the significance of duricrusts as indicators of important change in such basins.The detailed macromorphological, micromorphological, and geochemical study of three duricrust profiles revealed the sequence of pedogenic, vadose, and groundwater processes responsible for their formation. During the first stage of their development, carbonate laminae formed a white ''grill-like'' structure within the detrital parent materials. The microstructure and macrostructure of the carbonate, which includes alveolar septal structures and needle-fiber calcite, indicates the important role of roots and their associated microorganisms in calcrete formation. Early silicification occurred in the pedogenic-vadose environment affecting the detrital parent material, roots, and calcretes, forming an early silcrete defined by opaline glaebules and silica rhizoliths. The detailed preservation of the cells in the silicified roots denotes the early replacement of root organic matter. The green or green-yellowish fluorescence of the silicified root structures under short-wavelength UV shows their preferential enrichment in uranium. Calcitization and silicification coexisted in the pedogenic vadose environment, leading to several reversible replacements of calcite and silica. Later, the rise of the water table promoted silicification under phreatic conditions, as indicated by the good preservation of the texture of the detrital host rocks and calcretes. Other silcrete textures, such as ovoidal opaline accumulations, intraclasts produced by autobrecchification, and vadose silica cements, indicate later vadose environments, and consequently variations in the water table.The geochemical features of the calcretes and silcretes (major, minor, and rare earth elements) were inherited from their parent materials. The rare-earth-element patterns of some silcretes show them to have a positive Ce anomaly, suggesting that oxidizing conditions reigned during their formation. The good correlation between silica and uranium suggests that the silica phases acquired uranium through the direct silicification of roots that had fixed uranium from organic matter.This study shows that calcrete-silcrete duricrusts provide detailed information regarding the processes occurring in semiarid continental basins. In the studied basin, roots played a key role in both the development of the duricrust profiles and their enrichment in uranium. These duricrusts provide important information for understanding the overall stratigraphy of the studied basin and its large-scale ...

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“…A few specific examples of biogenic carbonate forms include calcified root cells, fungal filaments and rhizoliths (calcified roots; e.g. Becze-Deàk et al 1997;Jaillard et al 1991;Monger et al 1991), calcified earthworm biospheriods (Barta 2011), and the mineralisation of bacterial or fungal organic templates (Bindschedler et al 2014;Cailleau et al 2009). Another mechanism for the inclusion of SOC could be biomineralisation pathways such as the oxalate-carbonate pathway (Verrecchia 1990).…”

Section: Inclusionmentioning

confidence: 99%

Calcium-mediated stabilisation of soil organic carbon

2017

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Soils play an essential role in the global cycling of carbon and understanding the stabilisation mechanisms behind the preservation of soil organic carbon (SOC) pools is of globally recognised significance. Until recently, research into SOC stabilisation has predominantly focused on acidic soil environments and the interactions between SOC and aluminium (Al) or iron (Fe). The interactions between SOC and calcium (Ca) have typically received less attention, with fewer studies conducted in alkaline soils. Although it has widely been established that exchangeable Ca (Ca Exch ) positively correlates with SOC concentration and its resistance to oxidation, the exact mechanisms behind this relationship remain largely unidentified. This synthesis paper critically assesses available evidence on the potential role of Ca in the stabilisation of SOC and identifies research topics that warrant further investigation. Contrary to the common view of the chemistry of base cations in soils, chemical modelling indicates that Ca 2? can readily exchange its hydration shell and create inner sphere complexes with organic functional groups. This review therefore argues that both inner-and outer-sphere bridging by Ca 2? can play an active role in the stabilisation of SOC. Calcium carbonate (CaCO 3 ) can influence occluded SOC stability through its role in the stabilisation of aggregates; however, it could also play an unaccounted role in the direct sorption and inclusion of SOC. Finally, this review highlights the importance of pH as a potential predictor of SOC stabilisation mechanisms mediated by Al-or Fe-to Ca, and their respective effects on SOC dynamics.

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Structure and composition of calcified roots, and their identification in calcareous soils

Cited by 119 publications

References 8 publications

Plant-microbe-soil interactions in the rhizosphere: an evolutionary perspective

Plant-microbe-soil interactions in the rhizosphere: an evolutionary perspective

Root Calcretes and Uranium-Bearing Silcretes At Sedimentary Discontinuities In the Miocene of the Madrid Basin (Toledo, Spain)

Calcium-mediated stabilisation of soil organic carbon

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