Carbohydrates in Colobanthus quitensis and Deschampsia antarctica

Agnieszka I Piotrowicz-Cieślak,Ryszard J Górecki,Anna Bochenek,Irena Giełwanowska,Paweł Loro

doi:10.5586/asbp.2005.027

Agnieszka I Piotrowicz-Cieślak, Ryszard J Górecki + Show 3 more

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https://doi.org/10.5586/asbp.2005.027

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Abstract

Eight to nineteen ethanol-soluble carbohydrate components were identified in vegetative tissues of Colobanthus quitensis and Deschampsia antarctica. The analysed carbohydrates included: monosaccharides, cyclitols, galactosyl cyclitols, raffinose family oligosaccharides, lichnose family oligosaccharides, kestose family oligosaccharides. The analysed vegetative tissues accumulated from 447 to 139 mg/g d.m. soluble carbohydrates in Colobanthus quitensis, Deschampsia antarctica respectively. The raffinose family oligosaccharides constituted 53.3% in Colobanthus quitensis of the identified soluble carbohydrate component pool. Vegetative tissues accumulated starch in Colobanthus quitensis 20.6 mg/g d.m. and 261.6 mg/g d.m. in Deschampsia antarctica. Anatomical and ultrastructural observations of vegetative part of Colobanthus quitensis and Deschmpsia antarctica revealed the presence of various ergastic materials in intercellular spaces, cell walls and protoplasts. Various parts of these plants contain insoluble, PAS positive polysaccharides in intercellular spaces and in cell walls. Chloroplasts of analysed tissues contained starch. Less starch was visible in young, growing parts of shoots of Colobanthus quitensis and Deschmpsia antarctica, more starch appears in mature, differentiated parts.

Highlights

Plants have to be able to cope with severe abiotic stresses, caused by low temperature, repeated freezing and thawing, repeated desiccation, high irradiance and salinity (Alberdi et al 2002)
Acclimation to cold occurs by gradual adaptation to low temperature and involves a genetically programmed process that includes the synthesis of such compounds as proteins, lipids and soluble carbohydrates (Alberdi, Corcuera 1991)
Twenty one carbohydrate components were identified in vegetative tissues, including: monosaccharides, disaccharides, cyclitols, galactosyl cyclitols, raffinose family oligosaccharides, kestose family oligosaccharides and a polysaccharide starch

Summary

Introduction

Plants have to be able to cope with severe abiotic stresses, caused by low temperature, repeated freezing and thawing, repeated desiccation, high irradiance and salinity (Alberdi et al 2002). The major stress factors they have to face there are temperature and hydration, because the region has a cold and moist maritime climate. Acclimation to cold occurs by gradual adaptation to low temperature and involves a genetically programmed process that includes the synthesis of such compounds as proteins, lipids and soluble carbohydrates (Alberdi, Corcuera 1991). Soluble carbohydrates accumulating at low temperatures may have the dual function of storing carbon and providing cryoprotectants (Bachmann et al 1994). Raffinose family oligosaccharides (RFOs) are known to increase during cold acclimation in vegetative tissues (Castonguay, Nadeau 1998). RFOs solutions may promote transition of cellular contents to the vitreous (glassy) state that protects macromolecular structures during seed desiccation (Leopold et al 1994)

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