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Jonathan D. Bates - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH Vegetation Response to Western Juniper Slash Treatments
2016Co-Authors: Rick Miller, Jonathan D. BatesAbstract:Abstract The expansion of piñon–juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel reduction treatments and a cut-and-leave (CUT) treatment used to control western juniper (Juniperus occidentalis spp. occi-dentalis Hook.) of the northwestern United States. Treat-ments were; CUT, cut-and-broadcast burn (BURN), and cut-pile-and-burn the pile (PILE). A randomized complete block design was used with five replicates of each treat-ment located in a curl leaf mahogany (Cercocarpus le
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Vegetation Response to Western Juniper Slash Treatments
Environmental Management, 2013Co-Authors: Casey O’connor, Rick Miller, Jonathan D. BatesAbstract:The expansion of piñon–juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel reduction treatments and a cut-and-leave (CUT) treatment used to control western juniper ( Juniperus occidentalis spp. occidentalis Hook.) of the northwestern United States. Treatments were; CUT, cut-and-broadcast burn (BURN), and cut-pile-and-burn the pile (PILE). A randomized complete block design was used with five replicates of each treatment located in a curl leaf mahogany ( Cercocarpus ledifolius Nutt. ex Torr. & A. Gray)/mountain big sagebrush ( Artemisia tridentata Nutt. spp. vaseyana (Rydb.) Beetle)/Idaho fescue ( Festuca idahoensis Elmer) association. In 2010, 4 years after tree control the cover of perennial grasses (PG) [Sandberg’s bluegrass ( Poa secunda J. Pres) and large bunchgrasses] were about 4 and 5 % less, respectively, in the BURN (7.1 ± 0.6 %) than the PILE (11.4 ± 2.3 %) and CUT (12.4 ± 1.7 %) treatments ( P
Roland R. Dute - One of the best experts on this subject based on the ideXlab platform.
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Atomic force Microscopy of torus-bearing pit membranes
IAWA Journal, 2011Co-Authors: Roland R. Dute, Thomas ElderAbstract:Atomic force microscopy was used to compare the structures of dried, torus-bearing pit membranes from four woody species, three angiosperms and one gymnosperm. Tori of Osmanthus armatus are bipartite consisting of a pustular zone overlying parallel sets of microfibrils that form a peripheral corona. Microfibrils of the corona form radial spokes as they traverse the margo. Margo microfibrils are loosely packed thus facilitating passage of water molecules. The pustular layer is removed by acidified sodium chlorite. Tori of Cercocarpus montanus also have a pustular surface, but lack a corona. Tori of Pinus taeda have a finely granular to amorphous torus matrix. Ulmus alata tori have microfibrils traversing the surface. The atomic force microscope proves itself a useful tool for high resolution study of pit membranes with only minimal specimen preparation.
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Torus-Bearing Pit Membranes in Cercocarpus
IAWA Journal, 2010Co-Authors: Roland R. Dute, Jaynesh Patel, Steven JansenAbstract:Intervascular pit membranes of Cercocarpus possess torus thickenings. The thickenings, or pads, consist of lignified, secondary wall material. Torus pad deposition occurs late in cell ontogeny and is not associated with a microtubule plexus. Half-bordered pit pairs between tracheary elements and parenchyma cells often have a torus pad on the membrane surface facing the conducting cell. In contrast, a thick protective layer fills the pit cavity on the side of the parenchyma cell. Ontogeny of the torus thickenings in Cercocarpus represents a third mode of torus development in eudicots when compared to that occurring in Osmanthus/Daphne and Ulmus/Celtis.
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Pit membranes in tracheary elements of Rosaceae and related families: New records of tori and pseudotori
Various articles, 2007Co-Authors: Steven Jansen, Yuzou Sano, Brendan Choat, David Rabaey, Frederic Lens, Roland R. DuteAbstract:The micromorphology of pits in tracheary elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with an irregular distribution. Although these structures are toruslike under the light microscope, observations by electron microscopy illustrate that they represent ‘‘pseudotori’’ or plasmodesmata-associated thickenings. These thickenings frequently extend from the periphery of the pit membrane and form a cap-like, hollow structure. Pseudotori are occasionally found in few Elaeagnaceae and Rhamnaceae and appear to be related to species with fiber-tracheids and/or tracheids. True tori are strongly associated with round to oval pit apertures and are consistently present in narrow tracheary elements of Cercocarpus (Rosaceae), Planera (Ulmaceae), and ring-porous species of Ulmus and Zelkova (Ulmaceae). Vestured pits with homogenous pit membranes are reported for Hemiptelea (Ulmaceae). The homoplasticnature of pit membrane characteristics may be related to functional adaptations in terms of safety and efficiency of water transportor may reflect different developmental processes of xylem elements. These observations illustrate that there is more variation in angiosperm pits than previously thought.
Darlene Southworth - One of the best experts on this subject based on the ideXlab platform.
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Linking mycorrhizas to sporocarps: a new species, Geopora cercocarpi, on Cercocarpus ledifolius (Rosaceae).
Mycologia, 2011Co-Authors: Darlene Southworth, Jonathan L. FrankAbstract:Mycorrhizal assemblages characterized by molecular data frequently differ from collections of mycorrhizal sporocarps at the same site. Geopora species are frequent mycobionts of ectomycorrhizal roots, but except for G. cooperi they are rarely identified to species by molecular methods. Among the mycobionts of ectomycorrhizas with Cercocarpus ledifolius (Rosaceae) was a fungal species with a 91% BLAST match to G. arenicola. To determine the species of Geopora we surveyed for hypogeous sporocarps under C. ledifolius at sites in southern Oregon where the Geopora mycorrhizas had been collected and identified by DNA sequences of the ITS region. We found sporocarps of a Geopora species with 100% BLAST match to the mycorrhizas. Morphological characters of a white hymenium, inrolled entire margin and large spores, along with a hypogeous habit and a mycorrhizal host of C. ledifolius, distinguished these specimens from previously described species. Here we describe a new species, Geopora cercocarpi.
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Ectomycorrhizas of Cercocarpus ledifolius (Rosaceae)
American Journal of Botany, 2010Co-Authors: Kelly R. Mcdonald, Jason Pennell, Jonathan L. Frank, Darlene SouthworthAbstract:UNLABELLED PREMISE OF THE STUDY Woody species in the Rosaceae form ectomycorrhizal associations, but the fungal symbionts are unknown. The species of fungi determine whether host plants are isolated from other ectomycorrhizal species in the plant community or linked with other trees through mycorrhizal networks. In this study we identified the fungi that form ectomycorrhizas with Cercocarpus ledifolius (curl-leaf mountain mahogany). • METHODS Soil samples were collected under canopies of C. ledifolius. Ectomycorrhizas were described by morphology and by DNA sequences of the ITS region. Host species were confirmed by rbcL sequences. • KEY RESULTS Sixteen species of fungi were identified from ectomycorrhizas of Cercocarpus ledifolius. The ectomycorrhizal community was distinguished by the presence of a Geopora species situated in the G. arenicola clade and by the absence of Rhizopogon, suilloids, and Sebacinales. Of the species on C. ledifolius, two also occurred on trees of Quercus garryana var. breweri and four on Arctostaphylos sp. • CONCLUSIONS The presence of fungal species in common with other ectomycorrhizal hosts shows that C. ledifolius, Q. garryana var. breweri, and Arctostaphylos species could be linked by a mycorrhizal network, allowing them to exchange nutrients or to share inoculum for seedling roots and new fine roots. Single-host fungi limited to C. ledifolius may improve resource acquisition and reduce competition with other ectomycorrhizal hosts. The finding of a Geopora species as a frequent mycobiont of C. ledifolius suggests that this fungus might be appropriate for inoculating seedlings for habitat restoration.
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e ctomycorrhizas of Cercocarpus ledifolius r osaceae 1
2010Co-Authors: Kelly R. Mcdonald, Jason Pennell, Jonathan L. Frank, Darlene SouthworthAbstract: Premise of the study : Woody species in the Rosaceae form ectomycorrhizal associations, but the fungal symbionts are unknown. The species of fungi determine whether host plants are isolated from other ectomycorrhizal species in the plant community or linked with other trees through mycorrhizal networks. In this study we identifi ed the fungi that form ectomycorrhizas with Cercocarpus ledifolius (curl-leaf mountain mahogany). Methods : Soil samples were collected under canopies of C. ledifolius . Ectomycorrhizas were described by morphology and by DNA sequences of the ITS region. Host species were confi rmed by rbcL sequences. Key results : Sixteen species of fungi were identifi ed from ectomycorrhizas of Cercocarpus ledifolius. The ectomycorrhizal community was distinguished by the presence of a Geopora species situated in the G. arenicola clade and by the absence of Rhizopogon , suilloids, and Sebacinales. Of the species on C. ledifolius , two also occurred on trees of Quercus garryana var. breweri and four on Arctostaphylos sp. Conclusions : The presence of fungal species in common with other ectomycorrhizal hosts shows that C. ledifolius , Q. garryana var. breweri , and Arctostaphylos species could be linked by a mycorrhizal network, allowing them to exchange nutrients or to share inoculum for seedling roots and new fi ne roots. Single-host fungi limited to C. ledifolius may improve resource acquisition and reduce competition with other ectomycorrhizal hosts. The fi nding of a Geopora species as a frequent mycobiont of C. ledifolius suggests that this fungus might be appropriate for inoculating seedlings for habitat restoration.
Brian J. Wienhold - One of the best experts on this subject based on the ideXlab platform.
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DIVISION S-7-FOREST & RANGE SOILS Nitrogen Mineralization in Soils of a Chaparral Watershed in Arizona
2016Co-Authors: James O. Klemmedson, Brian J. WienholdAbstract:This study was undertaken to extend our knowledge of nutrient availability in soils of the Arizona chaparral. Our objective was to determine the effect of shrub species and topographic aspect on N mineralization of soils from a watershed in central Arizona and to relate N mineralization to other soil properties. Soil for an incubation study was collected from the 0- to 2- and 2- to 10-cm soil layers beneath the canopy of 32 randomly selected shrubs, eight each of birchleaf mountain mahogany (Cercocarpus betutoides Nutt. ex. Torr. & A. Gray) and shrub live oak (Quercus turbinetta Greene) from both north and south aspects. Neither cumulative N mineralization (Nm) nor po-tentially mineralizable N (N0) was influenced by shrub species or as-pect. Aspect significantly influenced NH4 released in the 2- to 10-cm layer, with greater amounts released in soils from north and south aspects. Both Nm and N0 were markedly higher in the 0- to 2-cm soi
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Aspect and species influences on nitrogen and phosphorus accumulation in Arizona chaparral soil‐plant systems
Arid Soil Research and Rehabilitation, 1992Co-Authors: James O. Klemmedson, Brian J. WienholdAbstract:Abstract To improve understanding of nutrient relationships and factors affecting nutrient patterns in chaparral ecosystems a study was conducted to quantify the effect of aspect and shrub species on accumulation of N and P in a mature chaparral ecosystem. Components of shrub biomass, litter, and soil were sampled from 32 randomly selected soil‐plant systems, eight each of Cercocarpus betuloides and Quercus turbinella on north and south aspects, and analyzed for N and P. Shrub species influenced dry matter accumulation, with Cercocarpus accumulating more biomass in leaves, stems, and litter than Quercus. Similarly, N concentration and accumulation were greater in Cercocarpus systems than in Quercus systems. This was attributed to the ability of Cercocarpus to form symbiotic relationships with actinomycetes capable of N fixation. Phosphorus accumulation was much greater in Cercocarpus biomass than in Quercus. Aspect significantly influenced P concentration of soil, with higher concentrations occurring on n...
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Effect of prescribed fire on nitrogen and phosphorus in Arizona chaparral soil‐plant systems
Arid Soil Research and Rehabilitation, 1992Co-Authors: Brian J. Wienhold, James O. KlemmedsonAbstract:Abstract To improve understanding of how prescribed fire affects N and P in chaparral soil‐plant systems, a study was conducted to compare the distribution and availability of N and P in soil‐plant systems before and after a burn. Distribution of N and P in biomass components, litter, and soil was measured for five Cercocarpus betuloides and eight Quercus turbinella soil‐plant systems and compared to the distribution of biomass, N, and P in the same 13 soil‐plant systems following a prescribed burn. Individuals of C. betuloides accumulated more dry matter, N, and P in their shoots, litter, and upper 2 cm of mineral soil than those of Q. turbinella. Burning resulted in a loss of dry matter and N and a redistribution of N and P in soil‐plant systems of both species. Nutrient availability of soil collected under the 13 shrubs before and after the burn was assessed using a pot culture technique with barley as a test plant. The availability of P was greater in postburn soils than in preburn soils, while availa...
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Nodulation and nitrogen accretion response of Cercocarpus betuloides seedlings to phosphorus supplementation and water availability
Plant and Soil, 1991Co-Authors: Brian J. Wienhold, James O. KlemmedsonAbstract:Greenhouse experiments were conducted to assess the effect of phosphorus (P) supplementation and water availability on incidence of nodulation and nitrogen (N) fixation by Cercocarpus betuloides seedlings. Phosphorus supplementation resulted in a two-fold increase in shoot and total dry matter of seedlings grown in a P-deficient soil. Seedlings grown in P-supplemented soil supported a larger number (4.8 vs. 0.3) and fresh mass (0.179 vs. 0.009 g) of nodules than did controls. Nitrogenase activity (acetylene reduction), N concentration and N accretion were greater for seedlings grown in P-amended soil than for controls.
Steven Jansen - One of the best experts on this subject based on the ideXlab platform.
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Torus-Bearing Pit Membranes in Cercocarpus
IAWA Journal, 2010Co-Authors: Roland R. Dute, Jaynesh Patel, Steven JansenAbstract:Intervascular pit membranes of Cercocarpus possess torus thickenings. The thickenings, or pads, consist of lignified, secondary wall material. Torus pad deposition occurs late in cell ontogeny and is not associated with a microtubule plexus. Half-bordered pit pairs between tracheary elements and parenchyma cells often have a torus pad on the membrane surface facing the conducting cell. In contrast, a thick protective layer fills the pit cavity on the side of the parenchyma cell. Ontogeny of the torus thickenings in Cercocarpus represents a third mode of torus development in eudicots when compared to that occurring in Osmanthus/Daphne and Ulmus/Celtis.
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Pit membranes in tracheary elements of Rosaceae and related families: New records of tori and pseudotori
Various articles, 2007Co-Authors: Steven Jansen, Yuzou Sano, Brendan Choat, David Rabaey, Frederic Lens, Roland R. DuteAbstract:The micromorphology of pits in tracheary elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with an irregular distribution. Although these structures are toruslike under the light microscope, observations by electron microscopy illustrate that they represent ‘‘pseudotori’’ or plasmodesmata-associated thickenings. These thickenings frequently extend from the periphery of the pit membrane and form a cap-like, hollow structure. Pseudotori are occasionally found in few Elaeagnaceae and Rhamnaceae and appear to be related to species with fiber-tracheids and/or tracheids. True tori are strongly associated with round to oval pit apertures and are consistently present in narrow tracheary elements of Cercocarpus (Rosaceae), Planera (Ulmaceae), and ring-porous species of Ulmus and Zelkova (Ulmaceae). Vestured pits with homogenous pit membranes are reported for Hemiptelea (Ulmaceae). The homoplasticnature of pit membrane characteristics may be related to functional adaptations in terms of safety and efficiency of water transportor may reflect different developmental processes of xylem elements. These observations illustrate that there is more variation in angiosperm pits than previously thought.