THE EFFECT OF LOCAL HEATING ON THE THERMOTOLERANCE OF LEAF AND ROOT-CELLS OF WINTER-WHEAT

The effect of high-temperature treatment (30, 35, and 40 degrees C) on the thermotolerance of the leaf and root cells of one-week-old seedli ngs of winter wheat (Triticum aestivum L.), cv. Mironovskaya 808, was studied. Heat was applied either to a whole plant or differentially to a leaf or root. In all cases, high-temperature treatment increased th e thermotolerance of the leaf cells, whereas the heat resistance of th e root cells either did not change significantly or decreased graduall y. The time course and extent of the tolerance of the leaf and root ce lls depended on temperature and on the heating procedure. It is sugges ted that, upon local heating, a signal is transmitted throughout the w hole plant and induces a change in thermotolerance in nonheated plant organs.