The Properties of Aqueous Solutions at Subzero Temperatures

Franks, Felix

doi:10.1007/978-1-4757-6952-4_3

Cited by 92 publications

(115 citation statements)

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“…Vitrification is the solidification of a liquid by increases in viscosity, not by crystallization (3). It is a second order phase transition that is detectable as an apparent shift in the baseline in DSC (4,5,9). Vitrified solutions, or glasses, are formed by reducing the concentration of a solvent relative to the solute or by cooling rapidly enough to avoid nucleation and crystal growth (4,5).…”

Section: Discussionmentioning

confidence: 99%

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Effects of Cooling Rate on Seeds Exposed to Liquid Nitrogen Temperatures

Vertucci¹

1989

Plant Physiol.

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The effect of cooling rate on seeds was studied by hydrating pea (Pisum sativum), soybean (Glycine max), and sunflower (Hehlanthus annuus) seeds to different levels and then cooling them to -1900C at rates ranging from 10C/minute to 7000C/ minute. When seeds were moist enough to have freezable water (> 0.25 gram H20/gram dry weight), rapid cooling rates were optimal for maintaining seed vigor. If the seeds were cooled while at intermediate moisture levels (0.12 to 0.20 gram H20 per gram dry weight), there appeared to be no effect of cooling rate on seedling vigor. When seeds were very dry (< 0.08 gram H20 per gram dry weight), cooling rate had no effect on pea, but rapid cooling rates had a marked detrimental effect on soybean and sunflower germination. Glass transitions, detected by differential scanning calorimetry, were observed at all moisture contents in sunflower and soybean cotyledons that were cooled rapidly. In pea, glasses were detectable when cotyledons with high moisture levels were cooled rapidly. The nature of the glasses changed with moisture content. It is suggested that, at high moisture contents, glasses were formed in the aqueous phase, as well as the lipid phase if tissues had high oil contents, and this had beneficial effects on the survival of seeds at low temperatures. At low moisture contents, glasses were observed to form in the lipid phase, and this was associated with detrimental effects on seed viability.The rate at which hydrated biological samples are cooled to subfreezing temperatures has a great effect on their subsequent viability (3, 10, 11). Most tissues exhibit a biphasic response to cooling rate in which they are severely damaged if cooled too slowly or too rapidly (3, 10, 1). The optimum rate is tissue dependent and is perhaps a function of the permeability ofthe plasmalemma to water (10, 1). Optimum rates range from about 3YC/h for whole plant tissues to about 2000C/min for red blood cells (10,11).In partially hydrated systems such as seeds, cooling rate has dramatic effects on tissue survival during exposure to low temperature. Rapid cooling of lettuce seeds, for example, can protect seeds from freezing injury (12), whereas rapid cooling ofsesame seeds can have detrimental effects ( 14).

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Section: Discussionmentioning

confidence: 99%

“…Vitrified solutions, or glasses, are formed by reducing the concentration of a solvent relative to the solute or by cooling rapidly enough to avoid nucleation and crystal growth (4,5). The temperature at which a glass occurs is strongly dependent on the solvent concentration (1,4,13,18).…”

Section: Discussionmentioning

confidence: 99%

Effects of Cooling Rate on Seeds Exposed to Liquid Nitrogen Temperatures

Vertucci¹

1989

Plant Physiol.

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“…Franks, 1982). This process is the same for any liquid, but here it will be explained by the example of the water-ice transition.…”

Section: Freezing and Vitrification Of Watermentioning

confidence: 92%

“…Nucleation can also proceed via heterogeneous nucleation, where the water molecules near a surface (such as the container walls), or large particles in the solution (such as dust, proteins etc), act as a catalyst for the formation of ice nuclei (e.g. Franks, 1982). For a critical nucleus to form, the water molecules in the volume represented by the circle must spontaneously arrange themselves (through Brownian motion) into a regular ice-like structure.…”

Section: Freezing and Vitrification Of Watermentioning

confidence: 99%

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Freezing, Drying, and/or Vitrification of Membrane– Solute–Water Systems

1999

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Membranes are often damaged by freezing and/or dehydration, and this damage may be reduced by solutes. In many cases, these phenomena can be explained by the physical behaviour of membranesolute-water systems. Both solutes and membranes reduce the freezing temperature of water, although their effects are not simply additive. The dehydration of membranes induces large mechanical stresses in the membranes. These stresses produce a range of physical deformations and changes in the phase behaviour. These membrane stresses and strains are in general reduced by osmotic effects, and possibly other effects of solutes-provided of course that the solutes can approach the membrane in question. Membrane stresses may also be affected by vitrification where this occurs between membranes. Many of the differences among the effects of different solutes can be explained by the differences in the cystallization, vitrification, volumetric, partitioning and permeability properties of the solutes.

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