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

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.

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Dormancy Variations in Common Purslane Seeds

Weed Science ◽

10.1017/s0043174500038248 ◽

1974 ◽

Vol 22 (6) ◽

pp. 535-540 ◽

Cited By ~ 13

Author(s):

G. H. Egley

Keyword(s):

Water Content ◽

Seed Viability ◽

High Water ◽

High Water Content ◽

Water Imbibition ◽

Immature Seeds ◽

Seed Age ◽

Common Purslane ◽

Black Seeds ◽

Mature Seeds

Common purslane (Portulaca oleraceaL.) seeds, produced by the same plants, had different degrees of dormancy. The dormancy variations were caused neither by low seed viability nor by location on the plant where seeds were produced. Seed water content and seed age at time of collection contributed to, but were not solely responsible for, the dormancy variations. Immature, brown seeds of high water content were less dormant than the more mature, black seeds of low water content. The immature seeds germinated better in the dark than did the more mature seeds. A puncture in the seed, over the radicle, broke purslane dormancy. Dormancy was not caused by blockage of water imbibition by seeds. Purslane dormancy developed during later stages of seed maturation on the mother plant.

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

Functional Plant Biology ◽

10.1071/pp9750253 ◽

1975 ◽

Vol 2 (3) ◽

pp. 253 ◽

Cited By ~ 8

Author(s):

B Acock

Keyword(s):

Water Content ◽

Turgor Pressure ◽

Bound Water ◽

Leaf Tissue ◽

High Water ◽

Leaf Water ◽

High Water Content ◽

Pressure Potential ◽

Matrix Bound ◽

Water Contents

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.

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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.

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Preparation and characterization of modified chitosan for in vitro controlled release of vitamin B12

Journal of Polymer Engineering ◽

10.1515/polyeng-2013-0094 ◽

2013 ◽

Vol 33 (8) ◽

pp. 757-765 ◽

Cited By ~ 1

Author(s):

Ahmed Awadallah-F ◽

Tahia B. Mostafa

Keyword(s):

Water Content ◽

Monomer Concentration ◽

High Water ◽

High Water Content ◽

Vitamin B ◽

Acryloyl Chloride ◽

Modified Chitosan ◽

Increase With Increase

Abstract Graft copolymerization of acrylonitrile and acryloyl chloride on to chitosan was prepared by γ-rays. Optimization of the grafting (%) was studied. The grafting (%) was observed to increase with increase in the irradiation dose and monomer concentration. The grafting percentages were about 52% and 36% from polyacrylonitrile and poly(acryloyl chloride), respectively. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the specimens. The modified chitosan was loaded with vitamin B12, demonstrated nearly 5.0±2.3% and 50.1±4.5% release in the media of pH 1.2 and 6.8, respectively, for amidoximated chitosan-grafted polyacrylonitrile and 3.6±1.1% and 36±2.4% in pH 1.2 and 6.8, respectively, for chitosan-grafted poly(acryloyl chloride), as determined by a traditional dissolution model. The modified chitosan specimens that uploaded with vitamin B12 displayed a more decremental release in the acidic medium than the neutral one. However, in order to incorporate in vivo gastrointestinal conditions, such as acidic pH and high water content in the stomach, low water content, and the presence of semi-solid mass in the large intestine, a new model, called flow through diffusion cell, was also used to study the drug release. The results of the two approaches produced different release profiles at the same pH values.

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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.

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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.

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Evaluation of an Immunoisolation Membrane Formed by Incorporating a Polyvinyl Alcohol Hydrogel within a Microporous Filter Support

Cell Transplantation ◽

10.1177/096368979700600607 ◽

1997 ◽

Vol 6 (6) ◽

pp. 585-595 ◽

Cited By ~ 2

Author(s):

Andrew R. Baker ◽

Ronald L. Fournier ◽

Jeffrey G. Sarver ◽

Jennifer L. Long ◽

Peter J. Goldblatt ◽

...

Keyword(s):

Polyvinyl Alcohol ◽

Water Content ◽

Structural Integrity ◽

High Water ◽

Membrane Properties ◽

High Water Content ◽

Hybrid Hydrogel ◽

Wide Range ◽

Pva Hydrogel

An immunoisolation membrane formed by incorporating a high water content polyvinyl alcohol (PVA) hydrogel into a microporous polyether sulfone (PES) filter has been investigated in this study. The PVA hydrogel is formed in situ within the filter pores via glutaraldehyde (GA) crosslinking under acidic conditions. The tortuous nature of the microporous filter pores securely anchors the embedded hydrogel to provide excellent structural integrity. The high void fraction of the PES filter support (>80%) and high water content of the PVA hydrogel (>85% water by weight) allow excellent solute transport rates, while an appropriate level of glutaraldehyde crosslinking supplies the required molecular size selectivity. In vitro permeability measurements made with solutes covering a wide range of molecular sizes demonstrate high transport rates for small nutrient molecules with rapidly diminishing permeabilities above a molecular weight of approximately 1,000 Dalton. Implantation experiments show that the membrane properties are not deleteriously affected by prolonged in vivo exposure or common sterilization techniques. Thus, this hybrid hydrogel/filter membrane system offers a promising approach to the immunoisolation of implanted cells.

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Disposable contact lenses and bacterial adhesion. In vitro comparison between ionic/high-water-content and non-ionic/low-water-content lenses

Biomaterials ◽

10.1016/0142-9612(95)99695-i ◽

1995 ◽

Vol 16 (9) ◽

pp. 685-690 ◽

Cited By ~ 22

Author(s):

Carla Renata Arciola ◽

Maria Cristina Maltarello ◽

Elisabetta Cenni ◽

Arturo Pizzoferrato

Keyword(s):

Water Content ◽

Bacterial Adhesion ◽

Contact Lenses ◽

High Water ◽

High Water Content ◽

In Vitro Comparison

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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.

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