On Heat-Shock Stimulation of Plant Cells Reparability

The effect of heat shock (5 min at 45 °C) on the cytoplasmic streaming in the cells of Campanula persicifolia, Zebrina pendula and Tradescantia albiflora leaves and the chloroplast phototaxis in the cells of T. albiflora has been investigated. It has been shown that heat shock not only increases the thermostability of these functions but also stimulates the cell reparatory ability. Cells preliminarily subjected to heat shock after test heating more rapidly restore heat suppressed functions than control cells that underwent test heating only, provided the degree of initial inhibition of functions was equal both in hardened and in control cells. The reparation rate of hardened cells immediately after test heating exceeds many-fold that of control cells. Moreover, heat shock widens the reparatory zone, that is a region of temperatures under which heating of definite duration suppresses a given function fully but reversibly. Thus heat shock intensifies the activity of the cell reparatory apparatus, the structure and action mechanisms of which are still unknown.