Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resist...

water and temperature are determinant factors for seed germination. both factors can, separately or jointly, affect the germination percentage and germination rate. the effect of temperature on germination and water potential on germination can often be described by the thermal time and hydrotime models, respectively. additionally, the thermal time model and the hydrotime model have been combin...

COIIMAN, M. D., BLEDSOE, C. S., and LOPUSHINSKY, W. 1989. Pure culture response of ectomycorrhizal fungi to imposed water stress. Can. J. Bot. 67: 29-39. The ability of ectomycorrhizal fungal isolates to tolerate imposed water stress in pure culture was examined in 55 isolates of 18 species. Water potential treatments, adjusted with polyethylene glycol, were applied to Petri dish units. These u...

Leaves, the distal section of the soil-plant-atmosphere continuum, exhibit the lowest water potentials in a plant. In contrast to angiosperm leaves, knowledge of the hydraulic architecture of conifer needles is scant. We investigated the hydraulic efficiency and safety of Pinus pinaster needles, comparing different techniques. The xylem hydraulic conductivity (k(s)) and embolism vulnerability (...

BACKGROUND/AIMS High viscosity silicone oils are used as tamponade agents to increase the resistance to emulsification; however, this makes the oils more difficult to inject. Increasing the extensional viscosity is one way to reduce emulsification. This study aimed to evaluate how silicone oils with increased extensional viscosity behave in terms of their ease of injection. METHODS The shear ...

Objective of this study was to evaluate the effects of long term water storage and ageing on the bond strength of resin composite cement to yttria-stabilized zirconium dioxide (zirconia) and dialuminium trioxide (alumina). Substrate specimens of alumina and zirconia were air particle abraded with dialuminium trioxide before priming and application of composite resin. Priming was made with gamma...

Alcanivorax borkumensis is an ubiquitous model organism for hydrocarbonoclastic bacteria, which dominates polluted surface waters. Its negligible presence in oil-contaminated deep waters (as observed during the Deepwater Horizon accident) raises the hypothesis that it may lack adaptive mechanisms to hydrostatic pressure (HP). The type strain SK2 was tested under 0.1, 5 and 10 MPa (corresponding...

The aim of this study was to assess the bond strength of a resin cement to intraradicular dentin varying the light-curing unit and the moment at which the light was applied. Post spaces of endodontically treated canines were prepared. The roots were distributed into 6 groups (n=10) according to the light-curing unit and the moment of light exposure: I) Quartz tungsten halogen-600 mW/cm² (QTH) +...

Abstract Seed germination is an important phase of plant development during which soil water availability is crucial. Salinity can affect seed germination in two ways: 1) Change of osmotic potential of available water, 2) toxicity effects. In this experiment, interactive effects of salinity and water deficit on germination criteria of two species of A, littoralis and A. logopoides were...

Olive trees (Olea europaea L.) in natural environments are increasingly being subjected to abiotic stresses, such as water deficit. Arbuscular mycorrhizal (AM) symbioses can improve olive tolerance In the current study, elucidate role of AM fungi regulating deficit resistance olive, effects Rhizophagus irregularis DAOM 197198 on gas exchange, stem potential, phytohormones, carbohydrates and ind...