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Titolo:
Membrane behaviour in seeds and other systems at low water content: the various effects of solutes
Autore:
Bryant, G; Koster, KL; Wolfe, J;
Indirizzi:
Univ S Dakota, Dept Biol, Vermillion, SD 57069 USA Univ S Dakota Vermillion SD USA 57069 Dept Biol, Vermillion, SD 57069 USA RMIT Univ, Dept Appl Phys, Melbourne, Vic 3001, Australia RMIT Univ Melbourne Vic Australia 3001 ys, Melbourne, Vic 3001, Australia Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia Univ New S Wales Sydney NSW Australia 2052 s, Sydney, NSW 2052, Australia
Titolo Testata:
SEED SCIENCE RESEARCH
fascicolo: 1, volume: 11, anno: 2001,
pagine: 17 - 25
SICI:
0960-2585(200103)11:1<17:MBISAO>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHASE-TRANSITIONS; PHOSPHOLIPID-BILAYERS; PLASMA-MEMBRANE; PHOSPHATIDYLCHOLINE; VITRIFICATION; DEHYDRATION; RELEVANCE; FORCES; ANHYDROBIOSIS; TEMPERATURE;
Keywords:
dehydration; desiccation; membranes; phase transition; solutes; sugars; vitrification;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Koster, KL Univ S Dakota, Dept Biol, Vermillion, SD 57069 USA Univ S Dakota Vermillion SD USA 57069 Vermillion, SD 57069 USA
Citazione:
G. Bryant et al., "Membrane behaviour in seeds and other systems at low water content: the various effects of solutes", SEED SCI R, 11(1), 2001, pp. 17-25

Abstract

A common feature of desiccation-tolerant organisms, such as orthodox seeds, is the presence of large quantities of sugars, especially di- and oligosaccharides. These sugars may be one component of the suite of adaptations that allow anhydrobiotes to survive the loss of most of their cellular water. This paper describes the physical effects of dehydration on cellular ultrastructure, with particular emphasis on membranes, and explains quantitatively how sugars and other solutes can influence these physical effects. As a result of dehydration, the surfaces of membranes are brought into close approach, which causes physical stresses that can lead to a variety of effects, including demixing of membrane components and fluid-to-gel phase transitions of membrane lipids. The presence of small solutes, such as sugars, between membranes can limit their close approach and, thereby, diminish the physical stresses that cause lipid fluid-to-gel phase transitions to occur during dehydration. Thus, in the presence of intermembrane sugars, the lipid fluid-to-gel phase transition temperature (T-m) does not increase as much asit does in the absence of sugars. Vitrification of the intermembrane sugarsolution has the additional effect of adding a mechanical resistance to the lipid phase transition; therefore, when sugars vitrify between fluid phase bilayers, T-m is depressed below its fully hydrated value (T-o). These effects occur only for solutes small enough to remain in very narrow spaces between membranes at low hydration. Large solutes, such as polymers, may be excluded from such regions and, therefore, do not diminish the physical forces that lead to membrane changes at low hydration.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 21:00:57