An Equilibrium Model of Leaf Water Potentials Which Separates Intra- and Extracellular Potentials

A model is proposed which makes it possible to estimate the intracellular turgor pressure potential, intracellular osmotic plus matric potential, and intra- and extracellular soIution fractions of water in leaf tissue at any water content. The model requires only the data normally collected with a thermocouple psychrometer: total water potential of live and dead (cells ruptured) tissue at various known water contents. The major assumptions are that (1) the total potential of water in the solution fraction in any part of the tissue multiplied by the volume of water is constant; (2) extracellular water experiences no pressure potential; (3) matrix-bound water is held only by matric forces and contains no solute; (4) the solution fraction of the intracellular water is constant at high water content; and (5) matrix-bound water content is constant over the range of leaf water contents normally examined. The models developed to deal with pressure bomb data are examined critically and doubts are cast on the validity of some of their assumptions.

Download Full-text

STUDIES IN TREE PHYSIOLOGY: I. GENERAL INTRODUCTION. WATER CONTENTS OF CERTAIN CANADIAN TREES

Canadian Journal of Research ◽

10.1139/cjr39c-043 ◽

1939 ◽

Vol 17c (12) ◽

pp. 460-482 ◽

Cited By ~ 11

Author(s):

R. Darnley Gibbs

Keyword(s):

Water Content ◽

Populus Tremuloides ◽

Weather Conditions ◽

High Water ◽

High Water Content ◽

White Pine ◽

General Introduction ◽

Very High ◽

Considerable Loss ◽

Water Contents

Previous work by the author on the water contents of Canadian trees is reviewed and followed by a brief discussion of questions yet to be answered.In Betula alba v. papyrifera, in at least the young parts of B. alba v. pendula laciniata, in B. populifolia, and in several sizes of Populus tremuloides, there is a marked seasonal rhythm in water content. The maximum is at leaf opening, the minimum at leaf fall. In poplar but not in birch there is a very high water content in December. During winter a considerable loss of water may occur. A winter loss is shown also by the wood of hemlock and larch and by twigs and leaves of white pine and hemlock. Losses from leaves are surprisingly small.The behaviour of B. populifolia has been studied for more than three years, and differences have been correlated with observations on weather conditions. Experimental work on movement of water in this species during winter is inconclusive. This work continues.

Download Full-text

Viability and germination of Scots pine seeds after freezing of harvested cones in vitro

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0107 ◽

2016 ◽

Vol 46 (8) ◽

pp. 1035-1041

Author(s):

Markku Nygren ◽

Katri Himanen ◽

Hanna Ruhanen

Keyword(s):

Water Content ◽

Scots Pine ◽

Seed Viability ◽

High Water ◽

Logistic Function ◽

High Water Content ◽

Maturation Stage ◽

Freezing Treatment ◽

Water Contents

Scots pine (Pinus silvestris L.) cone and seed water contents were analyzed in two consecutive seasons during maturation stage in the autumn and in January and March before seed dispersal. Cones with different water contents were subjected to 2 h of freezing at −30 °C, and seed viability and laboratory germination of seeds from individual cones after treatment were analyzed. Seed water content could be well predicted with the measurement of the cone water content, and the general relationship between these two could be described with a generalized logistic function. On average, the water content of cones was 5%–10% units higher than the seeds inside them. The higher the cone water content at the onset of freezing treatment, the higher the proportion of seeds with apparent damage (based on visual inspection of seeds using X-ray images) in that particular cone. High water content in cones also resulted in decreased germination after freezing treatment. The critical cone water content for 50% germination after freezing at −30 °C was approximately 31.3% (fresh mass basis). This corresponds to 21.6% water content in seeds.

Download Full-text

Soil-Water Separation Property of Bauxite Mine Slime

10.3233/atde210155 ◽

2021 ◽

Author(s):

Zhiqiang Wu ◽

Kai Xu ◽

Zhihuan Wang ◽

Shuaiheng Li ◽

Baoying Jiang

Keyword(s):

Water Content ◽

Bound Water ◽

Free Water ◽

High Water ◽

Load Application ◽

Separation Property ◽

High Water Content ◽

Application Process ◽

Water Separation ◽

Bauxite Mine

Traditional disposal of the high-water content slime from the beneficiating and washing of the bauxite mine requires lots of land and a long time to consolidate, which has attracted a wide range of environmental and social concerns. High-speed centrifugal test was carried out to investigate the water property and composition of high-water content bauxite washing mud. Test results indicated that the bound water content ranged from 29.7% to 31.4%, free water content ranged from 250.6% to 252.3%. The bound water accounted for only 11%, while the free water accounted for about 89% of total water content. A series of model tests were conducted to study the slurry-water separation property of high-water content bauxite mine slime. Experiments showed that controlling the vacuum load application process can effectively inhibit the formation of low-permeability stratum around the drainage body. The final settlement increased by 31.5% and the amount of water discharge increased by 39.52% compared with the conventional vacuum preloading method. Moreover, the water content may decrease from 281.9% to 53.6% within 60 hours with the increase of density of drainage body under the controlled vacuum load application process.

Download Full-text

Turgor Maintenance in Rosa rugosa Grown at Three Levels of Nitrogen and Subjected to Drought

Journal of Environmental Horticulture ◽

10.24266/0738-2898-8.3.108 ◽

1990 ◽

Vol 8 (3) ◽

pp. 108-112 ◽

Cited By ~ 1

Author(s):

R.M. Augé ◽

A.J.W. Stodola ◽

D.M. Gealy

Keyword(s):

Water Content ◽

Turgor Pressure ◽

N Fertilization ◽

Leaf Water ◽

Leaf Water Content ◽

Rosa Rugosa ◽

Turgor Maintenance ◽

Relative Water ◽

Complete Fertilizer ◽

Water Contents

Abstract The influence of N fertilization on turgor maintenance was determined in leaves from well-watered and droughted Rosa rugosa L. Plants were fertilized for 60 days with a complete fertilizer with N at levels of 0, 200 or 500 ppm and then subjected to several drought cycles for 22 days. Plants receivmg no N were stunted and chlorotic, but had the greatest full saturation turgor pressure and symplastic osmolality, and the lowest full saturation osmotic potential, after drought. These plants also maintained higher turgor across a range of leaf water potentials and relative water contents. Leaf water content at full turgor and relative water content at the turgor loss point were also lower in plants without N. N treatments of 200 and 500 ppm had similar water relations under both well-watered and drought conditions.

Download Full-text

Experimental Study on Dynamic Tensile Failure of Sandstone Specimens with Different Water Contents

Shock and Vibration ◽

10.1155/2019/7012752 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Ming Li ◽

Gang Lin ◽

Wei Zhou ◽

Xianbiao Mao ◽

Lianying Zhang ◽

...

Keyword(s):

Crack Propagation ◽

Water Content ◽

Water Saturation ◽

Water Injection ◽

High Water ◽

Tensile Failure ◽

High Water Content ◽

Dynamic Tensile Strength ◽

Macroscopic Crack ◽

Water Contents

Understanding the effect of water saturation on dynamic failure of rocks is of great importance to tunnel excavation at water-rich coal mines and prevention of rock bursts by water injection. Dynamic Brazilian disc tests are performed to study mechanical behaviour of sandstones in this paper. The results indicate that water saturation significantly weakens the dynamic tensile strength of sandstones and increases the specimen strain at which the specimen fails. The damage degree of sandstones reduces gradually with increasing water contents. Failure of the sandstone specimen includes the crack initiation at the center of the specimen, macroscopic crack propagation, and stretch of the macroscopic crack through the specimen. In addition, parallel macroscopic crack propagation is found in the specimen with a low water content. From the observation of fracture sections, microstructures are compact in the specimen with high water contents. This is due to the swell of the kaolinite in the specimen after water saturation. The failure mechanism of microstructures is typical brittle failure in the specimen with a high water content, whereas ductile fracture is found in the specimen with a low water content. Different failure processes of microstructures lead to the differences between mechanical properties and macroscopic failure characteristics of the specimens with various water contents.

Download Full-text

Nitrous oxide production and sources in response to a simulated fall-freeze-thaw cycle

10.5194/egusphere-egu2020-6227 ◽

2020 ◽

Author(s):

Sisi Lin ◽

Guillermo Hernandez Ramirez

Keyword(s):

Climate Change ◽

Water Content ◽

Soil Water ◽

High Water ◽

Organic N ◽

High Water Content ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Water Contents

Thaw-induced N2O emissions have been shown to account for 30-90% of N2O emissions in agricultural fields. Due to the climate change, increased precipitatio is expected in fall and winter seasons for certain regions. As a result, this would in turn enhance the thaw-induced N2O emissions and aggravate climate change. A mesocosm study was conducted to investigate N2O production and sources from soils under elevated soil moisture contents in response to a simulated fall-freeze-thaw cycle. Treatments included two levels of N addition (urea versus control) and two different management histories [with (SW) and without (CT) manure additions]. Our results showed that at least 92% of the N2O emissions during the study were produced during the simulated thawing across all treatments. The thaw-induced N2O emissions increased with increasing soil water content. The fall-applied urea increased the soil-derived N2O emissions during thawing, indicating an excessive mineralization of soil organic N. Compared to the CT soils, the SW soils induced more soil-derived N2O emissions. This could be because the SW soil had more easily decomposable organic matter which was likely due to historical manure additions. Regarding to the daily primed N2O fluxes, different soil water contents impacted the dynamics of daily priming effect. At the high water content, the soils experienced a shift in daily primed N2O fluxes from positive to negative and eventually back to positive throughout the simulated thawing, while the soils at lower water contents underwent positive primed fluxes in general. The shift in daily primed fluxes was probably driven by the preference of soil microbes on the labile N substrates. When the microbes switched from easily to moderately decomposed substrates (e.g., from dissolved organic N to plant residuals), they started to uptake inorganic N from the soil due to a relatively high C:N ratio of plant residuals. Therefore, a net N immobilization and negative primed N2O production occur in the short term in the soils at the high water content.

Download Full-text

The influence of leaf water content and isoprenoids on flammability of some Mediterranean woody species

International Journal of Wildland Fire ◽

10.1071/wf07075 ◽

2009 ◽

Vol 18 (2) ◽

pp. 203 ◽

Cited By ~ 24

Author(s):

Manuela De Lillis ◽

Pietro Massimiliano Bianco ◽

Francesco Loreto

Keyword(s):

Water Content ◽

Pinus Halepensis ◽

Negative Relationship ◽

High Water ◽

Leaf Water ◽

High Water Content ◽

Leaf Water Content ◽

Evergreen Species ◽

The Impact ◽

Isoprenoid Emission

The impact of water content and isoprenoids on leaf flammability was studied. Field and laboratory experiments were carried out on monoterpene-emitting evergreen broad-leaved species (Quercus ilex, Quercus suber); a needle-leaved species (Pinus halepensis) that emits and stores monoterpenes; an evergreen species (Myrtus communis) that emits isoprene but stores monoterpenes; and a deciduous species (Quercus pubescens) that emits isoprene. Photosynthesis, leaf water content (LWC) and isoprenoid emission were measured. Isoprenoid content was calculated. Temperatures of visible smoke, incandescence and flame appearance were recorded. The LWC significantly correlated with both photosynthesis and isoprenoid emissions. Linear correlation and factorial analysis revealed a positive correlation between temperature of flame appearance and LWC and a negative relationship between temperature of flame appearance and isoprenoid emission. Multiple regression analysis indicated that the temperature of flame appearance was reduced in broadleaved monoterpene-emitting species. In monoterpene emitters, the temperature of flame appearance depended for ~65% on LWC, whereas monoterpene emissions explained ~35% of the dependency. P. halepensis and M. communis, storing high levels of isoprenoids, ignited at high humidity. The results may be explained if isoprenoids indeed facilitate leaf ignition but, being dissolved in water, isoprenoids are also an indicator of a high water content that decreases flammability.

Download Full-text

Hydrogels as Antibacterial Biomaterials

Current Pharmaceutical Design ◽

10.2174/1381612824666180213122953 ◽

2018 ◽

Vol 24 (8) ◽

pp. 843-854 ◽

Cited By ~ 6

Author(s):

Weiguo Xu ◽

Shujun Dong ◽

Yuping Han ◽

Shuqiang Li ◽

Yang Liu

Keyword(s):

Mechanical Properties ◽

Drug Delivery ◽

Tissue Engineering ◽

Water Content ◽

Oxygen Permeability ◽

Structural Diversity ◽

High Water ◽

Clinical Applications ◽

High Water Content ◽

Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Download Full-text