The impact of season of harvest and duration of pre-measurement storage impact hydraulic conductance of stem samples for Acer rubrum L. x saccharinum L. and Fraxinus americana L.

Background It is typically assumed that within short time-frames, patient-specific peritoneal membrane characteristics are constant and do not depend on the initial fluid tonicity and dwell duration. The aim of this study was to check whether this assumption holds when membrane properties are estimated using the 3-pore model (3PM). Methods Thirty-two stable peritoneal dialysis (PD) patients underwent 3 8-hour peritoneal equilibration tests (PETs) with different glucose-based solutions (1.36%, 2.27%, and 3.86%). Temporary drainage was performed at 1 and 4 hours. Glucose, urea, creatinine, sodium, and phosphate concentrations were measured in dialysate and blood samples. Three-pore model parameters were estimated for each patient and each 8-hour PET separately. In addition, model parameters were estimated using data truncated to the initial 4 hours of peritoneal dwell. Results In all cases, model-estimated parameter values were within previously reported ranges. The peritoneal absorption (PA) and diffusive permeability for all solutes except sodium increased with fluid tonicity, with about 18% increase when switching from glucose 2.27% to 3.86%. Glucose peritoneal reflection coefficient and osmotic conductance (OsmCond), and fraction of hydraulic conductance for ultrasmall pores decreased with fluid tonicity (over 40% when switching from glucose 1.36%). Model fitting to the truncated 4-hour data resulted in little change in the parameters, except for PA, peritoneal hydraulic conductance, and OsmCond, for which higher values for the 4-hour dwell were found. Conclusion Initial fluid tonicity has a substantial impact on the 3PM-estimated characteristics of the peritoneal membrane, whereas the impact of dwell duration was relatively small and possibly influenced by the change in the patient's activity.

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Aquaporin Activity to Improve Crop Drought Tolerance

Cells ◽

10.3390/cells7090123 ◽

2018 ◽

Vol 7 (9) ◽

pp. 123 ◽

Cited By ~ 20

Author(s):

Avat Shekoofa ◽

Thomas Sinclair

Keyword(s):

Soil Water ◽

Water Conservation ◽

Production Systems ◽

Phloem Loading ◽

Hydraulic Conductance ◽

Water Deficit Stress ◽

Dry Land ◽

Physiological Processes ◽

Arachis Hypogaea L ◽

The Impact

In plants, aquaporins (AQP) occur in multiple isoforms in both plasmalemma and tonoplast membranes resulting in regulation of water flow in and out of cells, and ultimately, water transfer through a series of cells in leaves and roots. Consequently, it is not surprising that physiological and molecular studies have identified AQPs as playing key roles in regulating hydraulic conductance in roots and leaves. As a result, the activity of AQPs influences a range of physiological processes including phloem loading, xylem water exit, stomatal aperture and gas exchange. The influence of AQPs on hydraulic conductance in plants is particularly important in regulating plant transpiration rate, particularly under conditions of developing soil water-deficit stress and elevated atmospheric vapor pressure deficit (VPD). In this review, we examine the impact of AQP activity and hydraulic conductance on crop water use and the identification of genotypes that express soil water conservation as a result of these traits. An important outcome of this research has been the identification and commercialization of cultivars of peanut (Arachis hypogaea L.), maize (Zea mays L.), and soybean (Glycine max (Merr) L.) for dry land production systems.

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Impact of Cover Crop Usage on Soilborne Diseases in Field Nursery Production

Agronomy ◽

10.3390/agronomy9110753 ◽

2019 ◽

Vol 9 (11) ◽

pp. 753 ◽

Cited By ~ 1

Author(s):

Sujan Dawadi ◽

Fulya Baysal-Gurel ◽

Karla M. Addesso ◽

Jason B. Oliver ◽

Terri Simmons

Keyword(s):

Disease Severity ◽

Cover Crops ◽

Cover Crop ◽

Acer Rubrum ◽

Soilborne Pathogens ◽

Red Maple ◽

Damping Off ◽

Field Nursery ◽

Nursery Production ◽

The Impact

Soilborne pathogens are a significant economic problem for nursery production in the Southeastern United States. The goal of this study was to determine the impact of cover crops on soilborne disease suppressiveness in such systems. Soils from red maple (Acer rubrum L.) plantation fields grown with and without cover crops were sampled, either while the cover crops were growing (pre-disked) or post-season, following cover crop incorporation into the soil (post-disked). Greenhouse bioassays were conducted using red maple seeds on inoculated (with Rhizoctonia solani (J.G. Kühn) or Phytophthora nicotianae (Breda de Haan)) and non-inoculated field soils. The damping-off, root rot disease severity, percent recovery of Rhizoctonia and Phytophthora, and pseudomonad population were examined during the two years of the experiment. Results showed that cover crop incorporation was beneficial for inducing disease supressiveness characteristics of soil. Cover crop incorporation into the soil significantly or numerically reduced disease severity and pathogen recovery in infested soil compared to the bare soil treatment. Cover crop incorporation was found to be partially associated with the reduction of seedling damping-off. The pseudomonad microbial population was greater when cover crop was present, and is thought to be antagonist to soilborne pathogens. Therefore, cover crops can be integrated in field nursery production systems to suppress soilborne pathogens.

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Alterations in Vessel Size in Twigs Of Quercus Robur and Q. Petraea Upon Defoliation and Consequences For Water Transport Under Drought

IAWA Journal ◽

10.1163/22941932-90000162 ◽

2006 ◽

Vol 27 (4) ◽

pp. 395-407 ◽

Cited By ~ 7

Author(s):

Frank M. Thomas ◽

Christiane Bartels ◽

Thomas Gieger

Keyword(s):

Quercus Robur ◽

Ring Width ◽

Hydraulic Conductance ◽

Stress Factors ◽

Cross Sectional ◽

Size Classes ◽

Earlywood Vessel ◽

The Cross ◽

And Control ◽

The Impact

In the complex of natural factors responsible for damage to the Central European oak species Quercus robur and Q. petraea, repeated defoliation and drought are considered the most important ones. To investigate the impact of these factors on xylem anatomy and hydraulic conductance, saplings of both species were manually defoliated in the spring of two consecutive years, and equal fractions of defoliated and control saplings were subjected to drought stress in the third year of the study. Defoliation did not significantly reduce the annual ring width of the twigs, but in the twigs of Q. robur it resulted in a significant reduction of the cross-sectional area of early- and latewood vessels, and in a shift in the distribution of the earlywood vessel cross-sectional areas towards smaller size classes in the year after the first defoliation. In the earlywood of Q. petraea twigs, repeated defoliation led to a significant increase in the cross-sectional vessel areas and to a shift in their distribution towards larger size classes. No significant differences in the percentage loss of hydraulic conductance (PLC) occurred between trees that had been defoliated in two successive years prior to the drought experiment and control trees. However, PLC was significantly increased by drought. The different responses of the oak species are attributed to their different capability to recover from the applied stress factors.

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Hydraulic conductance of intact plants of two contrasting sorghum lines, SC15 and SC1205

Functional Plant Biology ◽

10.1071/fp12338 ◽

2013 ◽

Vol 40 (7) ◽

pp. 730 ◽

Cited By ~ 15

Author(s):

Sunita Choudhary ◽

Thomas R. Sinclair ◽

P. V. Vara Prasad

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Use ◽

Hydraulic Conductance ◽

Leaf Conductance ◽

Soil Drying ◽

Water Deficits ◽

Intact Plants ◽

The Impact

Low plant hydraulic conductance has been hypothesised as an approach to decrease the rate of soil water use, resulting in soil water conservation for use during late season water deficits. The impact of leaf hydraulic conductance (Kleaf) on water use characteristics was explored by comparing two sorghum (Sorghum bicolor (L.) Moench) genotypes that had been found to differ in Kleaf. Genotype SC15 had a much lower leaf conductance than genotype SC1205. Four sets of experiments were undertaken to extend the comparison to the impact of differences in Kleaf on the plant water budget. (1) Measurements of hydraulic conductance of intact plants confirmed that leaf conductance of SC15 was lower than that of SC1205. (2) The low leaf conductance of SC15 was associated with a decrease in transpiration during soil drying at a higher soil water content than that of SC1205. (3) SC15 had a restricted transpiration rate at vapour pressure deficits (VPD) above 2.1 kPa, whereas SC1205 did not. (4) Treatment with aquaporin inhibitors showed substantial differences in the sensitivity of the transpiration response between the genotypes. These results demonstrated that low Kleaf in SC15 was associated with conservative water use by restricting transpiration at higher soil water content during soil drying and under high VPD. Tests with inhibitors indicate that these differences may be linked to differences between their aquaporin populations. The differences between the two genotypes indicated that the traits exhibited by SC15 would be desirable in environments where soil water deficits develop.

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Sapwood Cuts and Their Impact on Tree Stability

Arboriculture & Urban Forestry ◽

10.48044/jauf.2012.038 ◽

2012 ◽

Vol 38 (6) ◽

pp. 287-292

Author(s):

E. Thomas Smiley ◽

Brian Kane ◽

Wesley Autio ◽

Liza Holmes

Keyword(s):

Mechanical Damage ◽

Acer Rubrum ◽

Cross Sectional Area ◽

Sectional Area ◽

Percent Reduction ◽

Quercus Acutissima ◽

Cross Sectional ◽

Decay Fungi ◽

Tree Stability ◽

The Impact

Sapwood may be lost due to wood decay fungi or mechanical damage. Assessing the impact of sapwood loss on the likelihood of tree failure has not been empirically tested. The purpose of this research was to determine the effect of the loss of sapwood on the flexural stiffness of tree trunks for different species and trunk sizes. Three tree species (Acer rubrum, Liquidambar styraciflua, and Quercus acutissima) were tested at two sites using pull testing techniques. A portion of the stem was mechanically removed and the trees were again pull tested. As the percent reduction in cross-sectional area increased, the percent reduction in stress to deflect trunks decreased linearly, regardless of species. Stress from sapwood loss was compared to an equivalent calculated loss in heartwood with the same cross-sectional area. The calculated loss of heartwood to cause an equivalent magnitude of stress was almost twice as large as cut area of sapwood. Trees were also tested by pulling in opposite directions with respect to sapwood loss. The percentage reduction in stress was greater for trees tested in compression.

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Carbon Footprint and Related Production Costs of Pot-in-Pot System Components for Red Maple Using Life Cycle Assessment

Journal of Environmental Horticulture ◽

10.24266/0738-2898-33.3.103 ◽

2015 ◽

Vol 33 (3) ◽

pp. 103-109 ◽

Cited By ~ 1

Author(s):

Dewayne L. Ingram ◽

Charles R. Hall

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Carbon Footprint ◽

Production Systems ◽

Ghg Emissions ◽

Acer Rubrum ◽

Production Costs ◽

Red Maple ◽

Bare Root ◽

The Impact

Component input materials and activities of a model pot-in-pot (PIP) production system were analyzed using life cycle assessment methods. The impact of each component on global warming potential (GWP; kilograms of CO2-equivalent), or carbon footprint, and variable production costs was determined for a 5 cm caliper Acer rubrum L. ‘October Glory’ in a #25 container. Total greenhouse gas emissions (GHG) of inputs and processes at the nursery gate for a defined model system were 15.317 kg CO2e. Carbon sequestration weighted over a 100-year assessment period was estimated to be 4.575 kg CO2, yielding a nursery gate GWP of 10.742 kg CO2e. The major contridbutors to the GWP at the nursery gate were the substrate, production container, the 1.8 m (6 ft), branched, bare root liner, PIP system installation, and fertilization while the liner and production container also contributed significantly to the variable costs. Input materials and labor constituted about 76 and 21% of variable costs, respectively. Unlike field production systems, equipment use in PIP production accounted for only 13% of GHG emissions and 2% of variable costs.

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Low-temperature Exotherms and Freeze Tolerance in Three Taxa of Deciduous Trees

HortScience ◽

10.21273/hortsci.30.4.849a ◽

1995 ◽

Vol 30 (4) ◽

pp. 849A-849

Author(s):

Orville M. Lindstrom ◽

Tomasz Anisko ◽

Michael A. Dirr

Keyword(s):

Low Temperature ◽

Cold Hardiness ◽

Acer Rubrum ◽

Freeze Tolerance ◽

Reliable Estimate ◽

Fraxinus Americana ◽

Deep Supercooling ◽

The Difference ◽

The Relationship ◽

Zelkova Serrata

Although differential thermal analysis has been routinely used to evaluate cold hardiness, the relationship between deep supercooling ability and plant survival is not clear. We compared seasonal profiles of changes in low-temperature exotherm (LTE) occurrence and visually determined lowest survival temperature (LST) of Acer rubrum `Armstrong', Fraxinus americana `Autumn Purple' and Zelkova serrata `Green Village' growing in three locations representing plant cold hardiness zones 8, 7 and 5. Between December and February, LTE in Acer rubrum and Fraxinus americana occurred at temperatures 10 to 25C lower than the LST. The difference between LTE and LST was not significant for Zelkova serrata from January to April, and for Acer rubrum and Fraxinus americana in March. Data indicate that LTE could be used as an estimate of LST in Zelkova serrata but not in Acer rubrum and Fraxinus americana. This study demonstrated that LTE does not provide a reliable estimate of cold hardiness in all species that deep supercool.

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Direct and indirect effects of a dense understory on tree seedling recruitment in temperate forests: habitat-mediated predation versus competition

Canadian Journal of Forest Research ◽

10.1139/x07-247 ◽

2008 ◽

Vol 38 (6) ◽

pp. 1634-1645 ◽

Cited By ~ 46

Author(s):

Alejandro A. Royo ◽

Walter P. Carson

Keyword(s):

Indirect Effects ◽

Vegetation Cover ◽

Acer Saccharum ◽

Resource Competition ◽

Seedling Recruitment ◽

Plant Cover ◽

Acer Rubrum ◽

Fagus Grandifolia ◽

Tree Seedling ◽

The Impact

In forests characterized by a dense woody and herbaceous understory layer, seedling recruitment is often directly suppressed via interspecific competition. Alternatively, these dense layers may indirectly lower tree recruitment by providing a haven for seed and seedling predators that prey on neighboring plant species. To simultaneously test for resource competition and indirect, habitat-mediated effects, we factorially manipulated understory plant cover (removed versus intact) and predation (exclosures versus controls) at three forested sites. We found that vegetation cover created privileged foraging areas that increased seed removal and seedling predation rates. Predator preference was directly related to seed size with larger seeded species including Prunus serotina Ehrh. and Fagus grandifolia Ehrh. removed more readily than smaller seeded species such as Fraxinus americana L. We found strong species-specific evidence for habitat-mediated indirect effects; establishment of P. serotina and Acer saccharum Marsh.was significantly lower under an intact hay-scented fern ( Dennstaedtia punctilobula (Michx.) T. Moore) canopy when small mammals were present. Competition also played a strong role; both P. serotina and Acer rubrum L. survival as well as A. rubrum emergence were reduced under a fern canopy with or without seed predators. The impact of habitat-mediated indirect effects and resource competition appear to vary predictably based upon predator preferences and differences in the timing of woody seed dispersal and germination relative to vegetation cover phenology. Overall, our results suggest that habitat-mediated indirect effects may be common and occur wherever vegetation provides the potential for creating privileged foraging areas.

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