Low temperature-induced accumulation of protein is sustained both in root meristems and in callus in winter wheat but not in spring wheat

Plant growth was assessed and cellular protein per nuclear DNA amount measured in root meristems and in callus derived from embryos of a spring ('Katepwa') and a winter variety ('Beaver') of allohexaploid wheat exposed to low temperature treatment. The data obtained were used to test whether these genetically distinct varieties of wheat responded differentially to cold treatment. Seedlings were grown for 14 d at 20 degrees C and then transferred to 4 degrees C for 14 d before returning them to 20 degrees C, or else were maintained continuously at 20 degrees C. In winter wheat, root growth at 4 degrees C was significantly greater over the first 7 d following transfer to 4 degrees C compared with plants retained at 20 degrees C, whereas in spring wheat it was reduced at 4 degrees C. The pattern of accumulation of cellular protein for both root meristem cells and in callus cells was also generally enhanced at 4 degrees C compared with 20 degrees C in winter wheat but not in spring wheat. Thus, clear inter-varietal differences were established both for dry weight accumulation and cellular protein, and the callus data clearly show that the low-temperature-induced accumulation of protein is a cellular phenomenon nor necessarily linked to development. The extent to which cold-shock proteins are a component of this low temperature-induced increase in cellular protein is discussed. (C) 2000 Annals of Botany Company.