Rate of accumulation of fructan oligomers in wheat seedlings (Triticum aestivum L.) during the early stages of chilling treatment.

The accumulation of soluble carbohydrates was studied during chilling of 2-week-old wheat (Triticum aestivum L.) seedlings. The extracts were analysed using a C18 HPLC method separating hexoses, sucrose and a wide range of oligofructan. Isomers were recognized and their content determined. The amounts of hexoses, sucrose and the trisaccharides 1-kestose and 6-kestose increased at the beginning of the treatment. The accumulation rate of 1-kestose, the trisaccharide generally considered to be the precursor of fructan, increased ten fold with some delay. Heavier fructan accumulated even later. In leaf blades, 1-3 molecular species with a degree of polymerization from 4 to 8 were detected. Five of these accounted for 90% of this pool at day 5. In leaf bases the amount of carbohydrates was lower but more species of fructan were detected. The sequence of accumulation was the same as in the blades. These results are discussed in relation to current models ot fructan synthesis.