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PHYSIOLOGICAL ADAPTATION OF EUROPEAN BEECH (FAGUS SYLVATICA L.) AND WILD CHERRY (PRUNUS AVIUM L.) SAPLINGS AFTER WINDTHROW
Authors: Svetoslav Anev* and Adriana Marinova
Number of views: 134
Variations in some physiological parameters of European beech (FS) and wild cherry (PA) saplings were studied in the second (2016), fifth (2019), and seventh year (2021) after windthrow disturbance in a monodominant European beech forest. Net photosynthetic rate (AN), transpiration rate (E), water-use efficiency (WUE), and total chlorophyll content (TCC) of FS and PA saplings were measured both in a windthrow site (W) and in a closed-canopy site (C). The physiological measurements in C-site were used as a control for the comparisons with W-site. European beech leaves on W-site had a positive photosynthetic response to higher light intensity only in 2019, while in the wild cherry leaves, similar increase was observed in 2016 and 2021. At the end of the study period, E of FS and PA leaves were equalized between W-site and C-site and between the two species. However, two years after windthrow, FS saplings had a similar transpiration rate in the two sample sites, while PA saplings had significantly higher transpiration in the W-site. In 2019, FS leaves managed to increase its Е in windthrow site, but it remained high in the PA’s leaves. WUE remained unchanged in W-site at the beginning of the experimental period for both species, but this physiological parameter was significantly higher in FS saplings. In 2019, the WUE in FS leaves was stabilized, while in the PA leaves, it even increased. In 2021, both species had stable levels of WUE. In W-site, the FS leaves had the same TCC throughout the experimental period, while such a parameter was higher in W-site in the PA leaves. Better physiological adaptation of PA to changed microclimatic conditions after the windthrow disturbance is probably the main reason for this species’ pioneer character and rapid colonization of the territory. The protective role of herbaceous plants, which invade in a windthrow site, allows FS to save the physiological activity and even increase physiological processes and parameters a few years after disturbances.