The importance of prenol lipids in mitigating salt stress in the leaves of Tilia × euchlora trees

Abstract

De-icing salt has been used on streets and pavements in most northern countries since the 1960s. Salt stress limits all vital functions of trees. Tilia × euchlora is planted in many cities given its unique decorative qualities. The aim of this study was to determine the tree strategy to mitigate salt stress due to the synthesis of polyprenols in leaves. Many years of observations have demonstrated that trees of the same species growing in the same street conditions may have extremely different health statuses. The study consisted of two experiments: a field experiment with urban street trees growing in saline soils and a controlled pot experiment with young trees exposed to increasing doses of salt. The differences between the young trees from the pot experiment and older trees from the field experiment were expressed in their ability to synthesize polyprenols. In urban conditions, the tree leaves with less damage contained signifcantly more polyprenols than did those with more damage. The salt stress mitigation strategy may be related to the ability to synthesize polyprenols. This ability can be acquired through adaptation by older trees. The mechanism involves limiting the transport of Cl− and Na+ to leaves. In the pot experiment, the young trees did not exhibit this ability.