Ascorbic (ASA) and Jasmonic acids (JA) have been commonly used experimentally to increase plant salt tolerance. Nevertheless, their application in farming is not cost-effective. Here we investigated the antioxidant effect of Hydroxytyrosol (HT), a phenolic compound found in olive mill wastewater (OMW), on salt tolerance in maize and wheat. The growth rate of wheat and maize roots and shoots under salinity conditions was reduced when compared to the control plants. However, the addition of HT improved the growth rate. Similar results were obtained when an equivalent concentration of ASA and JA was used. Whereas salt treatment dramatically reduced root cell wall pore diameter, ASA (a known effective molecule) and HT restored the root pore diameters. The salt treatment also significantly inhibited the transpiration rate. In addition, HT and ASA were found to expand the root pores and accelerate the root water uptake, consequently enhancing the transpiration rates. More specifically, extraction of a HT-rich fraction from OMW caused a similar physiological cascade of events, revealing significant plant growth increases. This was the first time that the effect of HT and ASA on the root cell wall pore size was reported. Consequently, our findings may shed light on a novel mechanism by which salinity and HT affect the water uptake potential via the pores. Therefore, we propose a method of disposing of OMW by maximizing its utilization in agriculture.
Bibliographical noteFunding Information:
This work was supported by the Israeli Ministry of Environmental Protection (grant number 192-3-1) and the European Union Peacebuilding Initiative (EUPI) under the “Unity and Diversity in Nature and Society” project (project agreement ENI/2019/412-148). In addition, it was supported partially by the Israeli Ministry of Science, Technology and Space and the Al-Qasemi Research Foundation. The authors gratefully acknowledge this financial support. The authors also thank Abeer Shehadeh for her technical support. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in, or financial conflict with, the subject matter or the materials discussed in the manuscript, apart from those disclosed.
© 2023, The Author(s), under exclusive licence to Brazilian Society of Plant Physiology.
- Cell wall pore size
- Growth rate
- Olive mill wastewater
- Transpiration rate
ASJC Scopus subject areas
- Agronomy and Crop Science
- Plant Science