Fructan metabolism in tall <i>fescue calli</i> under different environmental condition

Abstract

Several grasses usually accumulate high levels of fructans at low temperature or in the presence of high sugar supply. Fructans enhance plant resistance in adverse environmental conditions thanks to their vacuolar  localization which allow osmotic adjustments. Tall fescue calli do not show mature vacuoles due to its  anatomic characteristics, and these in vitro cultures can provide more knowledge about the fructan rule in  unspecialized tissues especially during stress conditions. The aim of this study was to evaluate the sugar  metabolism in embryogenic calli of tall fescue fed with different sucrose concentrations (0, 50 or 100 mM)  during growth culture, kept at “control” or “cold” temperatures (23 or 4°C, respectively). In the presence of  sucrose (50 or 100 mM), embryogenic calli accumulated fructans under control conditions. On the other hand,  the accumulation is inhibited by the simultaneously sugar supply and cold treatment while invertase activity  increased. From our data, cold temperature and high sucrose concentration seemed to be negatively  correlated in the fructans biosynthetic pathway in tall fescue in vitro cultures.

Key words: Cold, Festuca arundinacea, invertase, sucrose:sucrose fructosyltransferase (SST), sugars.