title: Assessing ambient ozone injury in olive (Olea europaea L.) plants by using the antioxidant ethylenediurea (EDU) in Saudi Arabia.
abstract: The antiozonant chemical, ethylenediurea (N-[2-(2-oxo-1-imidazolidinyl)ethyl]-N'-phenylurea, abbreviated as EDU), was applied as stem injections or soil drenches to 5-year-old containerized plants of olive (Olea europaea L. cultivar Kalamata) in growth chambers in order to assess its ameliorative effects against realistic ozone (O3) stress. Visible injury symptoms were reduced greatly in individuals treated with EDU, with injection applications having greater protection than soil drenches. EDU application caused increases in the measured ecophysiological parameters compared to untreated individuals. In particular, the stem injection protected plants against photosynthetic impairment (unchanged net photosynthetic rates and intercellular CO2 concentration, in comparison to plants grown in filtered air). EDU application increased the protection of PSII from ambient O3 oxidative stress, although it did not retain the proportion of redox state of QA, pigment composition of photosynthetic apparatus and size of light-harvesting complex of PSII. However, the stem injection of plants with EDU induced lower non-photochemical quenching (NPQ) values in comparison to ambient air (-2 %), indicating a better photoprotection of PSII in comparison to soil drench application. EDU application caused increases in the morphological and biometric parameters compared to individuals exposed to ambient air. To the best of our knowledge, this is the first study highlighting the protection of Kalamata olive trees due to EDU in terms of growth, yield, visible injury, and photosynthetic performance. Furthermore, this study proved that EDU could be a low-cost and a low-technology efficient tool for assessing O3 effects on plant performances in the field in Saudi Arabia.
authors.affiliation: Air Pollution Laboratory (APL), Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, P.O. Box 80216, Jeddah, 21589, Saudi Arabia.
authors.forename: J M
authors.initials: JM
authors.lastname: Basahi
authors.affiliation: Air Pollution Laboratory (APL), Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, P.O. Box 80216, Jeddah, 21589, Saudi Arabia.
authors.forename: I M
authors.initials: IM
authors.lastname: Ismail
authors.affiliation: Department of Chemistry, Faculty of Education, Alexandria University, Alexandria, Egypt.
authors.forename: N S
authors.initials: NS
authors.lastname: Haiba
authors.affiliation: Air Pollution Laboratory (APL), Centre of Excellence in Environmental Studies (CEES), King Abdulaziz University, P.O. Box 80216, Jeddah, 21589, Saudi Arabia.|Faculty of Science, Alexandria University, El Shatby, Alexandria, 21256, Egypt.
authors.forename: I A
authors.initials: IA
authors.lastname: Hassan
authors.affiliation: Department of Agriculture, Food and Environment, The University of Pisa, 56124, Pisa, Italy. giacomo.lorenzini@unipi.it.
authors.forename: G
authors.initials: G
authors.lastname: Lorenzini
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000975:Antioxidants / Q000494:pharmacology*; D004784:Environmental Monitoring / Q000379:methods*; D031658:Olea / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010126:Ozone / Q000633:toxicity*; D010671:Phenylurea Compounds / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects; D010935:Plant Diseases / Q000517:prevention & control*; D012529:Saudi Arabia
chemical_list: D000393:Air Pollutants; D000975:Antioxidants; D010671:Phenylurea Compounds; C032766:ethylene diurea; D010126:Ozone
keywords: Growth and yield; O3; Photosynthesis; Soil drench; Stem injection