Ethylene diurea (EDU) protection against ozone injury in tomato plants at Delhi.

Abstract

Air pollution has become an increasingly serious problem in developing countries. Ozone is the most phytotoxic gaseous air pollutant. Ground level ozone measurements carried out at Delhi during 1990 -1992 show that the ambient concentration of ozone varies between 20 to 273 μg m , and the one hour WHO ozone standard of 110.74 μg m , was violated on many occasions (Varshney and Aggarwal, 1992). Heck et al., 1982 have shown that out of total crop loss caused by air pollution in USA, about 90% of the crop loss is attributed to ozone. Ethylene diurea (EDU) has been shown to be specific in protecting plants against ozone injury because it is an strong anti-oxidant (Carnahan et al., 1978). Exploratory studies have been carried out to evaluate the protective role of EDU against ozone damage in cereals, legumes and vegetables (Astorino et al., 1995; Brennan et al., 1990; Brunschon-Harti, 1995; Clarke et al., 1990; Hofstra et al., 1978; Kostaka-Rick and Manning, 1992, 1993; Tonneijck and Vandijk, 1997). In India Bambawale (1986) have shown that the leaf spot disease of potato reported from Punjab in 1978 was primarily due to ozone pollution and foliar spray of EDU was found to reduce about 25-30%leaf spot disease. Higher yield in EDU-treated plants in comparison to untreated plants has been attributed to the specific protective effect of EDU against ozone damage (Clarke et al., 1990; Saettler, 1981; Smith et al., 1987).