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Cyrille Prestianni - One of the best experts on this subject based on the ideXlab platform.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (Middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquieres (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquières (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.
Nicolas Momont - One of the best experts on this subject based on the ideXlab platform.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (Middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquieres (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquières (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.
Javier Agusti - One of the best experts on this subject based on the ideXlab platform.
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A simple mathematical model of allometric exponential growth describes the early three-dimensional growth dynamics of Secondary Xylem in Arabidopsis roots
Royal Society open science, 2019Co-Authors: Anna Thamm, Sabina Sanegre-sans, Jennifer Paisley, Susana Meader, Ana Milhinhos, Sonia Antoranz Contera, Javier AgustiAbstract:Unravelling the specific growth dynamics of key tissues and organs is fundamental to understand how multicellular organisms orchestrate their different growth programmes. In plants, the Secondary growth (thickening) of stems and roots provides the mechanical support that plants need to achieve their developmental potential. We used conventional anatomical and microscopy techniques, image-processing software, and quantitative analysis to understand and mathematically describe the growth dynamics of the early developmental stages of Secondary Xylem (the main tissue developed during Secondary growth). Results show that such early developmental stages are characterized by exponential expansion of Secondary Xylem in three dimensions in the form of an inverted cone, with a power law that describes the relationship between the area of the base and the longitudinal progression (height) of the growing Secondary Xylem cone over time with a scaling exponent of 2/5: the signature of allometric growth. Our work constitutes a starting point for future modelling of Secondary Xylem in particular and Secondary growth in general.
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Supplementary Table 1_Cell count, areas and longitudinal extension from A simple mathematical model of allometric exponential growth describes the early three-dimensional growth dynamics of Secondary Xylem in Arabidopsis roots
2019Co-Authors: Anna Thamm, Sabina Sanegre-sans, Jennifer Paisley, Susana Meader, Ana Milhinhos, Sonia Antoranz Contera, Javier AgustiAbstract:Unravelling the specific growth dynamics of key tissues and organs is fundamental to understand how multicellular organisms orchestrate their different growth programmes. In plants, the Secondary growth (thickening) of stems and roots provides the mechanical support that plants need to achieve their developmental potential. We used conventional anatomical and microscopy techniques, image-processing software, and quantitative analysis to understand and mathematically describe the growth dynamics of the early developmental stages of Secondary Xylem (the main tissue developed during Secondary growth). Results show that such early developmental stages are characterized by exponential expansion of Secondary Xylem in 3D in the form of an inverted cone, with a power law that describes the relationship between the area of the base and the longitudinal progression (height) of the growing Secondary Xylem cone over time with a scaling exponent of 2/5: the signature of allometric growth. Our work constitutes a starting point for future modelling of Secondary Xylem in particular and Secondary growth in general
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Strigolactone-mediated Stimulation of Secondary Xylem Proliferation in Stems
Methods in molecular biology (Clifton N.J.), 2017Co-Authors: Javier AgustiAbstract:Secondary Xylem (wood) accounts for a large proportion of the terrestrial biomass. Understanding how Secondary Xylem develops and proliferates is a challenge to enhance our capacities for biomass production. Recent reports revealed that the plant hormone strigolactone is key for the development of Secondary Xylem. Here, I describe a protocol for strigolactone-mediated stimulation of Secondary Xylem proliferation in stems. The protocol has been tested in Arabidopsis and Eucalyptus and can be adjusted to other species.
Kishore S Rajput - One of the best experts on this subject based on the ideXlab platform.
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Development of successive cambia and formation of Secondary Xylem in Suaeda nudiflora and S. fruticosa (Amaranthaceae s.l.)
Flora, 2019Co-Authors: Ravindra A. Shelke, Amit D Gondaliya, K. K. Kapadane, D.g. Ramoliya, Kishore S RajputAbstract:Abstract Amaranthaceae s.l. and its allied families like Amaranthaceae s.s., Chenopodiaceae s.s. and Phytolaccaceae s.s. are always debated in the literature about their pattern of Secondary growth; when their stem diameter increases by forming successive cambia. In the present study, development of successive cambia and differentiation of its derivatives was investigated in Suaeda fruticosa and S. nudiflora (Amaranthaceae s.l.). After primary growth, the first complete ring of cambium was formed by the successive cambium due to failure in the development of interfascicular cambium between adjacent vascular bundles. The first ring of successive cambium initiated from the parenchymatous cells (pericyclic derivatives) external to the protophloem. This newly formed cambium was functionally bidirectional and produced Secondary Xylem centripetally and phloem centrifugally. Subsequent renewal of cambium was observed as small segments instead of complete ring. They interconnect with existing cambium and form anastomosing network. Due to the renewal of small sectors, the Secondary phloem formed by earlier cambial segments became enclosed within the Secondary Xylem and conjunctive tissue. Formation of vessels and sieve elements were found confined only to few fusiform cells while rest of the cambial sector exclusively produced conjunctive tissue on either side. The Secondary Xylem formed in the beginning of successive rings of Xylem remained rayless while thick stems showed presence of heterocellular rays with several cells in height and width. Accumulation of starch along with the presence of nuclei in the Xylem fibres even after deposition of the Secondary wall is consistent feature in both the species.
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structure and ontogeny of intraxylary Secondary Xylem and phloem development by the internal vascular cambium in campsis radicans l seem bignoniaceae
Journal of Plant Growth Regulation, 2018Co-Authors: Kishore S Rajput, Amit D Gondaliya, Manoj M Lekhak, Shrirang R. YadavAbstract:Bignoniaceae is known for the presence of different growth forms like trees, shrubs, lianas and herbs that show a wide range of variations in their wood structure. Trees, shrubs and lianas are characterised by the presence of normal Secondary growth except the lianoid forms of the tribe Bignonieae that have a unique type of the cambial variant (that is, wedged/furrowed Xylem) whereas other lineages lack it. Campsis radicans belongs to tribe Tecomeae and thus is expected to lack the cambial variant but it develops a quantifiable amount of intraxylary Secondary Xylem and phloem in the pith. Therefore, the main aim of the present investigation is to elucidate the ontogeny of intraxylary phloem and the Secondary Xylem formed by internal vascular cambium. Development of intraxylary phloem is delayed significantly as compared to other families of eudicots that show the presence of intraxylary phloem. Subsequently, a functionally bidirectional complete ring of internal vascular cambium initiates along the pith margin that produces Secondary Xylem centrifugally and Secondary phloem centripetally. In thick stems, an internal vascular cambium forms quantifiable amounts of inversely oriented Secondary Xylem and phloem that completely replace the pith. Structurally, this Secondary Xylem remains similar to the Xylem formed by the regular (external) cambium. It is composed of vessels, fibres, axial and ray parenchyma cells while the Secondary phloem consists of sieve elements, companion cells, axial and ray parenchyma cells. The development of internal vascular cambium completely replaced the parenchyma of the pith by producing intraxylary Secondary Xylem and phloem. The reason for the occurence of intraxylary phloem in C. radicans remains unknown. However, to the lesser extent it may be playing a Secondary role in conductive safety of the conduit.
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Development of Inverse Cambia and Structure of Secondary Xylem in Ipomoea turbinata (Convolvulaceae)
Polish Botanical Journal, 2017Co-Authors: Kishore S RajputAbstract:AbstractStructural transformation of mechanical tissues during the shift from a freestanding to a climbing habit is a characteristic of lianas, which are increasingly abundant in tropical forests. The modification of mechanical tissue and the evolution of a new growth pattern serve to increase stem flexibility and conductive efficiency. In Ipomoea turbinata Lag. (Convolvulaceae), the stem thickens via the formation of two distinct types of successive cambia: functionally normal successive cambia (producing Xylem centripetally and phloem centrifugally), and inverse cambia (producing Xylem centrifugally and phloem centripetally). The former originates from pericyclic derivatives (parenchyma cells located outside the primary phloem), while the latter originates from the conjunctive parenchyma located on the inner margin of the Secondary Xylem formed from vascular cambium. The Secondary Xylem produced by normal cambia is significantly more abundant than the Xylem formed by inverse cambia. During primary growth, intraxylary primary phloem differentiates concomitantly with the protoXylem at the periphery of the pith; additional intraxylary Secondary phloem is added from adjacent parenchyma cells as the plant ages. During initiation of every successive cambium, middle cells in the meristem give rise to cambium, and cells on either side of it serve as sites for initiation of future cambia. The functional role of inverse cambia remains unknown and awaits further experimental studies.
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Multiple cambia and Secondary Xylem of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae)
Acta Botanica Gallica, 2013Co-Authors: Kishore S Rajput, Vidya S. Patil, Karumachi S. RaoAbstract:AbstractStructure of Secondary Xylem and pattern of Secondary thickening in climbing species are different from those in self-supporting plants. In many climbing species, stem diameter increases by forming more than one ring of cambium (referred to as multiple/successive cambia), while their Secondary Xylem usually contains abundant parenchyma, large vessels and wide rays. In beach morning glory (Ipomoea pes-caprae (L.) R. Br., Convolvulaceae), stem thickness increases by forming multiple rings of cambia. After a short period of normal Secondary growth, the first successive cambium ensues from the pericyclic parenchyma. Thereafter, subsequent cambial rings originate from parenchyma cells produced initially by the previous cambium. In stems that are 15–20 mm thick, parenchymal cells produced by the initial activity of the previous cambia become meristematic and form small arcs of functionally inverse cambia that produce Secondary Xylem centrifugally and Secondary phloem centripetally. Unequal production of...
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Occurrence of rayless Secondary Xylem in some Indian herbaceous species
Israel Journal of Plant Sciences, 2001Co-Authors: Kishore S RajputAbstract:(Received 28 December 2000 and in revised form 26 February 2001) Absence of rays was observed in the Secondary Xylem of thirteen species from seven genera of Aizoaceae, Chenopodiaceae, and Polygonaceae. Among the species studied, all the members of Polygonaceae had normal Secondary Xylem, whereas in Aizoaceae and Chenopodiaceae the vascular cylinder of the mature stem was composed of successive rings of Xylem alternating with phloem bands. All the species of Chenopodiaceae and Polygonaceae accumulated scanty Secondary Xylem composed of vessels, tracheids, libriform fibers, and axial parenchyma, while in Aizoaceae, in addition to the above-mentioned cell types, fibriform vessels and fiber tracheids were also observed. In the latter part of Secondary growth in both Chenopodium species, some of the axial parenchyma underwent transverse division and formed a group of vertically elongated, procumbent cells, referred to here as pedomorphic rays. In all species studied, nuclei were retained in the lumen of Xylem...
Philippe Gerrienne - One of the best experts on this subject based on the ideXlab platform.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (Middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquieres (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.
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New information, including anatomy of the Secondary Xylem, on the genus Brabantophyton (Stenokoleales) from Ronquières (middle Devonian, Belgium)
Review of Palaeobotany and Palynology, 2016Co-Authors: Nicolas Momont, Anne-laure Decombeix, Philippe Gerrienne, Cyrille PrestianniAbstract:Two pyrite permineralized stems and one root are reported from the upper Middle to lowermost Late Devonian (middle Givetian to lowermost Frasnian) locality of Ronquières (Belgium) and identified as Brabantophyton runcariense Momont et al. (Stenokoleales). The stems include a three-ribbed protostele with a central protoXylem strand and other strands disposed along the midplanes of the ribs; each specimen shows Secondary Xylem. Tracheids of both primary and Secondary Xylem show circular to elliptical, multiseriate bordered pits. Rays are 1–seriate to 4–seriate; their height is highly variable, ranging from 3 to more than 100 cells. The root includes a four-ribbed protostele. Each rib shows two exarch protoXylem strands. The root also comprises a ring of Secondary Xylem identical to that of the stems. The characteristics of the Secondary vascular anatomy of Brabantophyton appear closer to the seed plants than to any other Devonian plant lineage. However, the presence of a bifacial vascular cambium is not demonstrated, which precludes a definitive assignment of the genus to the lignophytes. A hypothesis about the ontogenetic development of Brabantophyton is proposed on the basis of the different characteristics observed in the different stem specimens of the plant.