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David T. Bell - One of the best experts on this subject based on the ideXlab platform.
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Ecological response syndromes in the flora of southwestern Western Australia: Fire resprouters versus reseeders
The Botanical Review, 2001Co-Authors: David T. BellAbstract:Es können zwei Syndrome in bezug auf Waldbrände für Vegetationsarten des mediterranen Klimas im Südwesten Westaustraliens beschrieben werden. Pflanzen, die nach dem Waldbrand wieder austreiben, songenannte “resprouter,” überleben als Individuen. Pflanzen, die vom Feuer vernichtet werden, müssen sich durch Keimung der Samen und des Aufwachsens der Sämlinge neu etablieren (sogenannte “reseeder”). Eine Analyse der Strategien als Reaktion auf Waldbrände ergab für Pflanzenarten in Westaustralien, daß 50% der Proteaceae, 50% der Restionaceae, 45% der Orchidaceae, und 25% der Epacridaceae “resproter” sind. Innerhalb der Familie der Proteaceae sind Pflanzen, die wieder austreiben, anteilsmäßig zu 56% in Adenanthos , zu 52% in Hakea , zu 35% in Dryandra , und zu 31% in Grevillea vertreten. 49% der Banksia Arten sind “resprouter,” und es erscheint, daß das Syndrom der Wiederausbreitung durch Samen ein abgeleitetes Merkmal in deiser Familie ist. Der Anteil der “resprouter” beträgt in Pflanzengemeinschaften im Südwesten Westaustraliens 66 bis 80%. Diese prozentualen Anteile sind im allgemeinen höher als in mehr wüstenähnlichen Gebieten Westaustraliens und in vergleichbaren Pflanzengemeinschaften anderer mediterraner Klimate. Der relativ hohe Anteil von “resprouter” innerhalb Pflanzenfamilien un Pflanzengemeinschaften ist wahrscheinlich ein Anzeichen dafür, daß die Vegetation in Westaustralien stärker von der Einwirkung des Feuers geprägt ist als andere Gebiete mediterranen Klimas. Westaustralische Pflanzengemeinschaften haben ihren höchsten Grad an Vielfalt in frühen Jahren nach einem Waldbrand, wenn die Vegetation ein hohe Anzahl von Pflanzenarten und Individuen enthält, die “reseeder” sind. Samenbanken dominieren durch Samen von “reseeder.” Es gibt keine grundlegenden Unterschiede zwischen “resprouter”- und “reseeder”-Pflanzen in bezug auf mittlerer Samenmasse, Überlebensfähigkeit oder Keimfähigkeit der Samen. Allerdings neigen die Samen der “reseeder”-Pflanzen zu einem engeren Temperaturoptimum währen der Keimung. Der Erfolg der Landbesiedelung hängt vornehmlich von Samenmasse, Sämlingsgröße und Blattökophysiologie und Morphologie ab und weniger von der Strategie als Reaktion auf Waldbrände. Sämlinge von “reseeder”-Pflanzen wachsen in der Regel schneller als Sämlinge von “resprouter”-Pflanzen. Die grundlegende Buschmorphologie unterscheidet sich im allgemeinen zwischen “reseeder”-Pflanzen, die eine Regenschirmform, und “resprouter”-Pflanzen, die eine Vasenform annehmen. “Reseeder”-Pflanzenarten besitzen zumeist ein flaches, fibriliäres WurzelSystem. “Resprouter”-Pflanzen besitzen ein massives, tief durchdringendes WurzelSystem. Trieb: Wurzel-Verhältnisse von einjährigen Sämlingen und ausgewachsenen Pflanzen sind höher für “reseeder”-Pflanzen. “Resprouter”-Sämlinge speichern Stärke im Wurzelgewebe in höherem Maße als “reseeder”-Sämlinge. Obwohl essentielle Nährstoffkonzentrationen in Sämlingen nicht differieren zwischen “reseeder” und “resprouter,” konservieren “reseeder”-Pflanzen, Nährstoffe in größerem Ausmaß durch Blatterhalt. “Reseeder”-Pflanzen neigen zu einer erhöhten Produktion der Blütenanzahl und einer größeren Menge von bestäubten Blüten. ZüchtungsSysteme hingenen, die zu einer höheren Samenanlage in “reseeder”-Planzen führen, können zwischen strikter Fremdbestäubung und beträchtlicher Selbstbestäubung variieren. Es ist unwahrscheinlich, daß “reseeder”-Pflanzenarten vom Wind bestäubt werden. Das Überleben von Pflanzenarten in einer von Waldbränden geprägten Umwelt kann eine Reihe von Kombinationen von Attributen einschleißen. Es erscheint, daß in westaustralischen “reseeder”-Pflanzenarten der Mangel an der Unfähigkeit, neu auszutreiben, durch eine Anzahl anderer struktureller und funktioneller Merkmale kompensert wird. Kenntnisse der Strategien von Pflanzen im Südwesten Westaustraliens gegen Waldbrände können das Feuermanagement Regime, die Erhaltung seltener Arten und die Erneuerung der Vegetation nach einer Störung beeinflussen. Zusälzliche Kenntnisse der Strategien gegen Waidenbrände von Arten in der südwest-Avestaustralischen Flora sollen zu besserem Umgang mit natürlichen und erneuerten Pflanzengemeinschaften der Region führen. Two fire-response syndromes can be described for species of the vegetation of Mediterranean-climate, southwestern Western Australia. Resprouters survive fires as individuals. Reseeders are killed by fire and must reestablish through germination and establishment of seedlings. Of the Western Australian plant families analyzed for fire-response strategies, 50% of the Proteaceae, 50% of the Restionaceae, 45% of the Orchidaceae, and 25% of the Epacridaceae are resprouter species. Within genera of the Proteaceae, the proportions of resprouters include Adenanthos (56%), Hakea (52%), Dryandra (35%), and Grevillea (31%). Within Banksia , 49% are resprouters, and it appears that the reseeding syndrome is the derived character in this genus. The proportion of resprouters within southwestern Western Australian plant communities ranges from 66% to 80%. These percentages are generally higher than in more arid parts of Western Australia and in comparable plant communities from other Mediterranean-type climates of the world. The relatively high proportion of resprouters within plant families and within plant communities probably indicates that the Western Australian vegetation experiences a harsher fire stress regime than do other Mediterranean-type climate areas. Western Australian plant communities have their highest diversity in the early years after fire, when the vegetation contains a higher number of reseeding species and individuals. Seed banks are dominated by the seeds of reseeders. There are no basic differences in mean seed mass, viability, or germinability of seeds between resprouting species and reseeding species, but reseeders tend to have narrower optimum germination temperature regimes. Establishment success is related more to seed mass, seedling size, and leaf ecophysiology and morphology than to fire-response strategy. Reseeder seedlings tend to grow faster than do resprouter seedlings. Basic shrub morphology differs, with reseeders generally being umbrella shaped and resprouters urn shaped. Reseeding species most commonly have a shallow, Fibrous Root System. Resprouters have a massive, deeply penetrating Root System. Shoot:Root ratios of first-year seedlings and mature plants are higher for reseeders. Resprouter seedlings store starch in Root tissue at a much greater rate than do reseeder seedlings. Although the concentrations of essential nutrients in seedlings are not different between fire-response types, reseeders tend to conserve nutrients to a greater extent through leaf retention. Reseeders tend to produce greater numbers of flowers and greater amounts of floral rewards, but the breeding Systems, which lead to the higher seed set in reseeders, can vary between strict outcrossing and considerable selfing. Reseeding species are not likely to be wind pollinated. Species survival in a fire-prone environment can involve a wide range of combinations of attributes. It appears that in Western Australian reseeder species the lack of an ability to resprout is compensated for by a number of other structural and functional features. Knowledge of the fire-response strategies of species of southwestern Western Australia can influence fire-regime management, conservation of rare species, and restoration of vegetation after disturbance. Further knowledge of the fire-response strategies of species of the southwestern Western Australian flora should result in better management of natural and restored plant communities of the region.
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Ecological response syndromes in the flora of southwestern Western Australia: Fire resprouters versus reseeders
Botanical Review, 2001Co-Authors: David T. BellAbstract:Two fire-response syndromes can be described for species of the vegetation of Mediterranean-climate, southwestern Western Australia. Resprouters survive fires as individuals. Reseeders are killed by fire and must reestablish through germination and establishment of seedlings. Of the Western Australian plant families analyzed for fire-response strategies, 50% of the Proteaceae, 50% of the Restionaceae, 45% of the Orchidaceae, and 25% of the Epacridaceae are resprouter species. Within genera of the Proteaceae, the proportions of resprouters include Adenanthos (56%), Hakea (52%), Dryandra (35%), and Grevillea (31%). Within Banksia, 49% are resprouters, and it appears that the reseeding syndrome is the derived character in this genus. The proportion of resprouters within southwestern Western Australian plant communities ranges from 66% to 80%. These percentages are generally higher than in more arid parts of Western Australia and in comparable plant communities from other Mediterranean-type climates of the world. The relatively high proportion of resprouters within plant families and within plant communities probably indicates that the Western Australian vegetation experiences a harsher fire stress regime than do other Mediterranean-type climate areas. Western Australian plant communities have their highest diversity in the early years after fire, when the vegetation contains a higher number of reseeding species and individuals. Seed banks are dominated by the seeds of reseeders. There are no basic differences in mean seed mass, viability, or germinability of seeds between resprouting species and reseeding species, but reseeders tend to have narrower optimum germination temperature regimes. Establishment success is related more to seed mass, seedling size, and leaf ecophysiology and morphology than to fire-response strategy. Reseeder seedlings tend to grow faster than do resprouter seedlings. Basic shrub morphology differs, with reseeders generally being umbrella shaped and resprouters urn shaped. Reseeding species most commonly have a shallow, Fibrous Root System. Resprouters have a massive, deeply penetrating Root System. Shoot:Root ratios of first-year seedlings and mature plants are higher for reseeders. Resprouter seedlings store starch in Root tissue at a much greater rate than do reseeder seedlings. Although the concentrations of essential nutrients in seedlings are not different between fire-response types, reseeders tend to conserve nutrients to a greater extent through leaf retention. Reseeders tend to produce greater numbers of flowers and greater amounts of floral rewards, but the breeding Systems, which lead to the higher seed set in reseeders, can vary between strict outcrossing and considerable selfing. Reseeding species are not likely to be wind pollinated. Species survival in a fire-prone environment can involve a wide range of combinations of attributes. It appears that in Western Australian reseeder species the lack of an ability to resprout is compensated for by a number of other structural and functional features. Knowledge of the fire-response strategies of species of southwestern Western Australia can influence fire-regime management, conservation of rare species, and restoration of vegetation after disturbance. Further knowledge of the fire-response strategies of species of the southwestern Western Australian flora should result in better management of natural and restored plant communities of the region.
K. C. Steiner - One of the best experts on this subject based on the ideXlab platform.
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Growth and biomass partitioning of northern red oak and yellow- poplar seedlings: effects of shading and grass Root competition
Forest Science, 1990Co-Authors: T. E. Kolb, K. C. SteinerAbstract:(...) In all environments, shoot-Root ratio and partitioning of leaf and Root biomass to surface area for yellow-poplar was greater than oak. In response to competition for soil resources, both species increased biomass partitioning to the Root at the expense of the shoot. In response to shading, yellow-poplar increased leaf area proportion, while oak did not. Thinner leaves and a more Fibrous Root System were more important in explaining yellow-poplar's higher relative growth rate under conditions of shading and Root competition compared to oak than differences in shoot-Root weight ratio or plasticity in biomass partitioning
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Growth and biomass partitioning of northern red oak and yellow- poplar seedlings: effects of shading and grass Root competition
Forest Science, 1990Co-Authors: T. E. Kolb, K. C. SteinerAbstract:A study undertaken to increase understanding of morphological and physiological characteristics that influence the establishment and early growth of tree seedlings in highly competitive environments. Seedling growth of northern red oak (Quercus rubra) and yellow poplar (Liriodendron tulipifera) was studied outdoors in Pennsylvania from June 1985 to September 1986. Seedlings were grown from seed in each of 4 environments: 100% sun/no grass; 100% sun/grass; 37% sun/no grass; and 37% sun/grass. Leaf, stem and Root biomass, and projected surface areas of leaves and Roots, were measured by destructive harvests in each year. Growth allocation to organs was compared among environments by coefficients of the allometric equation Y = aXb. Total seedling biomass of oak was greater than yellow poplar in all environments and harvests because of an initial growth advantage from larger seed reserves. However, biomass relative growth rate of yellow poplar was greater than oak in all environments. Grass Root competition reduced biomass of both species, but more for yellow popular than for oak. In the absence of grass, shading reduced biomass of both species, especially yellow poplar, while shading in the presence of grass resulted in a nonsignificant increase in biomass of both species. In all environments, Root:shoot ratio and partitioning of leaf and Root biomass to surface area was greater in yellow poplar than in oak. In response to competition for soil resources, both species increased biomass partitioning to the Root at the expense of the shoot. In response to shading, yellow poplar increased leaf area proportion, while oak did not. Thinner leaves and a more Fibrous Root System were more important in explaining the greater relative growth rate under conditions of shading and Root competition in yellow poplar compared to oak than were differences in Root:shoot weight ratio or plasticity in biomass partitioning.
Christophe Perin - One of the best experts on this subject based on the ideXlab platform.
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Novel insights into the genomics of rice Root adaptive development
Rice Genetics V, 2020Co-Authors: Christophe Perin, J. Rebouillat, J. C. Breitler, P. Gantet, Anne Dievart, Brigitte Courtois, A. M. C. Brasileiro, Alexander A. T. Johnson, Nourollah Ahmadi, M. De RaissacAbstract:Deciphering the genetic and molecular mechanisms controlling the development of the Root System and its adaptive plasticity under adverse environments is of primary importance for the sustainable establishment of the rice crop. Rice displays a complex Root structure comprising several Root types mostly of postembryonic origin. The large natural variation in Root architecture among cultivars reflects their adaptation to contrasting agro-environmental conditions. This article reviews the current knowledge on the organization and anatomy of the various types of Roots of the Fibrous Root System of rice, the diversity and genetic basis of natural variation of Root System architecture and performance, and the molecular mechanisms underlying constitutive and adaptive Root development. This paper also throws light on how the integrated approach of new tools in high-resolution microscopy imaging, expression profiling, mutant screening, and reverse genetics could facilitate the rapid discovery and analysis of the key genes and regulatory networks involved in Root architectural traits affecting plant performance under field conditions.
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Genetic control of Root development in rice, the model cereal
Trends in Plant Science, 2010Co-Authors: Yoan Coudert, Christophe Perin, Brigitte Courtois, Ngan Giang Khong, P. GantetAbstract:Cereals possess a Fibrous Root System that is mainly composed of crown Roots that emerge postembryonically from the nodes of the stem. Because the Root System is not directly accessible and consequently difficult to study, it remains a target for breeders to improve the ability of plants to exploit the mineral and water resources of the soil. Breeding for Root architecture necessitates identifying the genetic determinants of Root development. This research is now underway in cereals, particularly in rice, the monocot model species. In this review, we examine recent data identifying genes that govern Root development in cereals, such as ARL1/CRL1 in rice and RTCS in maize which encodes a conserved lateral organ boundary domain transcription factor involved in crown Root initiation and development in response to auxin. Finally, we discuss the detection and validation of Root development quantitative trait loci.
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Molecular genetics of rice Root development
Rice, 2009Co-Authors: J. Rebouillat, Günter Giese, J. C. Breitler, P. Gantet, S. Espéout, Emmanuel Guiderdoni, Anne Dievart, Jean-luc Verdeil, Jacques Escoute, Christophe PerinAbstract:Abstract Plant Roots have a large range of functions, including acquisition of water and nutrients, as well as structural support. Dissecting the genetic and molecular mechanisms controlling rice Root development is critical for the development of new rice ideotypes that are better adapted to adverse conditions and for the production of sustainably achieved rice yield potential. Most knowledge regarding the gene networks involved in Root development has been accumulated in the model dicotyledon plant species Arabidopsis thaliana. Rice, the model monocotyledon species, presents several singularities compared to A. thaliana, including a Root architecture characterized by a Fibrous Root System comprising five types of embryonic and postembryonic Roots. The anatomy and morphology of the rice Root System, which is typical for a cereal, differs from that of A. thaliana, for instance, by the presence of a lysigenous cortex and additional cell layers compared to the dicotyledon model. Moreover, the structure and functions of the Root apical meristem (RAM) of rice are distinct from those of A. thaliana. Recently, several rice Root mutants have been identified via forward or reverse genetics, and these will aid in forming hypothesis to characterize either the divergence or conservation of genetic pathways relative to A. thaliana. Furthermore, these mutants will help to identify key genes in rice Roots that may be missing in A. thaliana. This review summarizes both classical and recent data concerning the molecular genetics of rice Root development, including Root anatomy and morphology, RAM structure, RAM patterning, and Root mutants.
Hui Ming - One of the best experts on this subject based on the ideXlab platform.
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Influence of hybrid giant Napier grass on salt and nutrient distributions with depth in a saline soil.
Biodegradation, 2012Co-Authors: Chongjian Ma, Ravi Naidu, Hui MingAbstract:Cultivation of the biofuel plant, hybrid giant Napier grass (HGN), in saline soil was investigated in a greenhouse study. The results show that HGN is a salt tolerant plant which can flourish in saline soil and product a large amount of biomass. The extensively developed Fibrous Root System of HGN plays a significant role in the uptake of sodium from saline soil so that both soil salinity and pH are reduced. Fibrous Roots of HGN are well distributed in the soil below the surface, where the metabolism of the Root System produces a gradient at the depth between 10 and 20 cm in soil salinity, pH and organic content. The degradation of the HGN by the biota within the soil results in an increase in nutrients and improved soil quality. The experimental results suggest that HGN adapts to saline soil, which is promising for phytoremediation of such soils. Additional advantages of HGN include the large biomass produced which can be used for renewable energy generation.
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Influence of hybrid giant Napier grass on salt and nutrient distributions with depth in a saline soil
Biodegradation, 2012Co-Authors: Chongjian Ma, Changhua Lin, Faguang Liu, Ravi Naidu, Hui MingAbstract:Cultivation of the biofuel plant, hybrid giant Napier grass (HGN), in saline soil was investigated in a greenhouse study. The results show that HGN is a salt tolerant plant which can flourish in saline soil and product a large amount of biomass. The extensively developed Fibrous Root System of HGN plays a significant role in the uptake of sodium from saline soil so that both soil salinity and pH are reduced. Fibrous Roots of HGN are well distributed in the soil below the surface, where the metabolism of the Root System produces a gradient at the depth between 10 and 20 cm in soil salinity, pH and organic content. The degradation of the HGN by the biota within the soil results in an increase in nutrients and improved soil quality. The experimental results suggest that HGN adapts to saline soil, which is promising for phytoremediation of such soils. Additional advantages of HGN include the large biomass produced which can be used for renewable energy generation. © 2012 Springer Science+Business Media B.V.
Bao Mei Yang - One of the best experts on this subject based on the ideXlab platform.
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Arsenic uptake by two vegetables grown in two soils amended with As-bearing animal manures
Journal of Hazardous Materials, 2009Co-Authors: Li Xian Yao, Zhao Huan He, Chang Min Zhou, Guo-liang Li, Zhi Dang, Bao Mei YangAbstract:Organoarsenicals are widely used as growth promoters in animal feed, resulting in unabsorbed arsenic (As) left in animal manures. A pot experiment was conducted to investigate the growth and As uptake of amaranth (Amaranthus tricolor Linn, a crop with an axial Root System) and water spinach (Ipomoea aquatica Forsk, a crop with a Fibrous Root System) grown in a paddy soil (PS) and a lateritic red soil (LRS) amended with 2% and 4% (w/w) As-bearing chicken manure and pig manure, respectively. Soils without any fertilizers were the controls. The biomass, As contents and total As uptake of the shoots, As transfer factors (TFs) from Roots to shoots and the Root/shoot (R/S) ratios of water spinach were significantly higher than those of amaranth (p < 0.0015). The biomass, total As uptake and R/S ratios showed significant difference for soil types (p < 0.0031). Manure amendments increased the biomass of both vegetables, reduced the As contents in amaranth but increased those in water spinach. The As contents were negatively correlated with the biomass in amaranth, but positive correlation was observed for water spinach. The total As uptake by amaranth was decreased in PS and insignificantly affected in LRS by manure application, but that by water spinach was significantly increased in both soils. We suggest that the higher As uptake by water spinach might be related to its Root structure and R/S ratio. Heavy application of As-bearing animal manures should be avoided in water spinach. © 2008 Elsevier B.V. All rights reserved.
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Arsenic uptake by two vegetables grown in two soils amended with As-bearing animal manures.
Journal of hazardous materials, 2008Co-Authors: Guo-liang Li, Zhao Huan He, Chang Min Zhou, Zhi Dang, Bao Mei YangAbstract:Organoarsenicals are widely used as growth promoters in animal feed, resulting in unabsorbed arsenic (As) left in animal manures. A pot experiment was conducted to investigate the growth and As uptake of amaranth (Amaranthus tricolor Linn, a crop with an axial Root System) and water spinach (Ipomoea aquatica Forsk, a crop with a Fibrous Root System) grown in a paddy soil (PS) and a lateritic red soil (LRS) amended with 2% and 4% (w/w) As-bearing chicken manure and pig manure, respectively. Soils without any fertilizers were the controls. The biomass, As contents and total As uptake of the shoots, As transfer factors (TFs) from Roots to shoots and the Root/shoot (R/S) ratios of water spinach were significantly higher than those of amaranth (p