P. SASHEVA1, R. YORDANOVA2, T. JANDA3, G. Szalai3 and L. MASLENKOVA2
1 Medical University of Sofia, Faculty of Pharmacy, BG – 1000 Sofia, Bulgaria
2 Institute of Plant Physiology and Genetics, BAS, BG – 1113 Sofia, Bulgaria
3 Agricultural Institute, Centre for Agricultural Research, HAS, H-2462, Martonvasar, Hungary
SASHEVA, P., R. YORDANOVA, T. JANDA, G. Szalai and L. MASLENKOVA, 2013. Study of primary photosynthetic reactions in winter wheat cultivars after cold hardening and freezing. Effect of salicylic acid. Bulg. J. Agric. Sci., Supplement 2, 19: 45–48
Thermoluminescence emission in winter wheat cultivar “Sadovo-1”, subjected to short period of low positive temperatures (cold hardening) and subzero temperatures (freezing) was measured in order to determinate changes in the redox cycling of Photosystem 2 centers and in the assimilatory potential in chloroplasts. Freezing stress seems to have pivotal a role in the accumulation of bound and free o-HCA forms, while levels of endogenous SA had slight increase. Subjecting the plants on freezing provoked a strong increase in plasma membrane leakage in no hardened plants. Dynamic changes of levels of free proline content were estimated after exposure of plants to low positive temperatures and subsequent freezing. Hardening effect of low positive temperatures was manifested by doubled gap of POD activity in the leaves of nonhardened winter wheat plants.