[Effect of oligosaccharides on adaptation of winter wheat seedlings to negative temperature].

We studied the dynamics of endogenous content of bioactive oligosaccharides in the roots of winter wheat seedlings. Previously these oligosaccharides proved to mediate development of frost resistance during the first days of hardening (Zabotina et al., 1998). The changes in their endogenous content can be described by a single-humped curve peaking 6 h after the onset of frost hardening. The capacity of these polysaccharides to increase frost resistance (LT50 was evaluated by leakage of electrolytes) when added to growth medium did not depend on the pretreatment duration (from 1.5 to 18 h) but decreased if they were introduced in the course of the adaptive response. Inhibition of the adaptive response by inhibitors of RNA and protein synthesis was ceased in the presence of the oligosaccharides. We believe that the oligosaccharides that are products of metabolism of the cell wall polysaccharides are involved in adaptation to low temperature.