Special issue in honour of Prof. Reto J. Strasser - Monitoring seasonal damage of photosynthetic apparatus in mature street trees exposed to road-side salinity caused by heavy traffic

Abstract

De-icing salts are harmful for road-side greenery. The aim of our study was to examine photosystem II performance in mature trees growing along a road of heavy traffic in relation to shoot and soil salinity caused by de-icing salts. Leaves from each three specimens of Aesculus hippocastanum, Tilia cordata, and Betula pendula growing along the same road, nine leaves from a road-side part (RS) and nine from an opposite part (OS) of each tree crown, were sampled in June, July, and September, 2017 and 2018. The PSII performance in RS and OS leaves was compared using chlorophyll a fluorescence (ChF) technique. Since the beginning of the both growing seasons, several parameters of ChF were different in OS and RS leaves, especially maximum quantum yield of primary photochemistry and efficiency of electron movement beyond plastoquinone QA- markedly decreased in RS leaves. However, PSII performance was not directly bound to shoot/soil salinity.