Assessment of the impact of drought stress on particular biochemical and physiological characteristics of beech saplings leaves from different provenances.

There were studied particular biochemical and physiological characteristics of European beech (Fagus sylvatica L.) saplings of different origin, responding to different water supply. Three different provenances (PV1, PV2, and PV3) representing the lower margin, the upper margin of beech distribution range and the optimal growth and environmental conditions for this species were investigated in a control (well-watered) and a drought treatment. For each provenance, the water potential values (Ψw) towards the end of the experiment were found low, indicating a severe water stress. However, there were not observed significant differences in decreasing Ψw values between the studied provenances. There were also recorded significant decreasing osmotic potential values (Ψs) influenced by drought. In the saplings of the PV2 provenance, the plants deprived of watering (drought treatment) showed the largest decrease of osmotic potential values. All provenances showed significant impacts of drought on the content of assimilatory pigments (Chl a, Chl b, Chl a + b, Chl a/b, Chl/Car). Nevertheless, the observed changes in individual provenances did not differ significantly. The analysis of the response to the controlled water deficit confirmed that the proline content increased significantly for all provenances. The largest increase in the proline concentration was observed in PV2 provenance. These results imply that the most sensitive to water deficit was the provenance PV2 from the optimal ecological beech area. [ABSTRACT FROM AUTHOR]