Impact of ozone on appearance of leaf injuries and changes in selected biochemical parameters of white clover (Trifolium repens L.)

Abstract

An investigation of the impact of ozone on the appearance of leaf injuries and changes in selected biochemical parameters in white clover were conducted in frames of the research of the effects of ozone on growth and development on selected agricultural plants species. For this purpose, we used the methodology of the International Cooperative Programme-Crops (ICP-Crops). Two sampling sites in the vicinity of meteorological and air pollution measurement stations were chosen: Iskrba near Kočevje, as not polluted, rural area in Slovenia and Ljubljana as a site within larger city area. The presence of ozone and its phytotoxic effects was monitored using cultivars of white clover. The response of agricultural plants to ozone and other photooxidants was monitored using the prescribed protocol based on observation of typical ozone induced leaf chlorosis, harvesting of biomass and measurements of selected physiological and biochemical parameters in the leaves. We tried to correlate quantitative visible leaf damage with ozone measurements in the air. In our experiment we investigated the effect of ethylenediurea (EDU) treatment of white clover, which is considered to protect plants against ozone injuries. Our investigation confirmed that ozone concentrations measured in Slovenia can produce harmful effects on white clover. EDU did not totally protect white clover against ozone.