Iris sibirica has unusual, practically non-different heat tolerance of PSII at different geographical exposures on the Bükk-plateau (North-Hungary)

: Heat tolerance of photosystem II (PSII) was examined in Siberian flag ( Iris sibirica L.) living in different microhabitats of a non-forested enclosed depression surface (doline) on the Bükk-plateau. Although the microclimatic parameters of the habitats with different facing sites show sharp contrasts, there was no significant difference between the heat tolerance of PSII in leaves of I. sibirica growing in these expositions neither in dark- nor in light-adapted state. in air temperature, air and soil humidity, which requires special adaptation/acclimation strategies, especially against the temperature. In this paper, we present some preliminary results on the unusual, practically non-different heat tolerance of I. sibirica growing in different exposures.