Special issue in honour of Prof. Reto J. Strasser - Photosynthetic efficiency of two Platanus orientalis L. ecotypes exposed to moderately high temperature - JIP-test analysis

Abstract

Plane (Platanus orientalis) is a popular park tree in Europe but is almost extinct in natural ecosystems, because of climate changes. In our study, two ecotypes of plane tree (Bulgarian and Italian) were submitted to moderately elevated temperature that occurs in summer. Our aim was to compare stress reactions, tolerance, and adaptability of these plants. Leaf age had a significant impact on the stress effects. For correct interpretation of the results, we investigated leaves at different positions from the apical bud, i.e., leaves of different age. We assessed their photosynthetic efficiency at room temperature and after treatment at moderately high temperature by simultaneous measurement of prompt and delayed chlorophyll fluorescence, as well as light reflection at 820 nm. For more precise interpretation of the obtained results we did principal component analysis. The two studied plane ecotypes showed different tolerance to the elevated temperature. Plants of Italian ecotype showed better adaptivity and developed advantageous photosynthetic characteristics, while Bulgarian ecotype was more affected. Plants of both ecotypes recovered from the heat stress.