EFFECT OF FUEL EMISSIONS ON TOMATO FRUITS (Solanum lycopersicum) AND TWO OF ITS FUNGAL PATHOGENS

Abstract

The quantity of carbon dioxide (CO2) and carbon monoxide (CO) produced by generators and motor vehicles which are the major sources of air pollution have increased with increase in the use of generators and vehicles. The component gases analysed for this study were CO, CO2, HC and O2. Due to their hazardous effect on living things such as plants and animals in the environment, it will be important that more attention be paid to these gaseous pollutants. Healthy, mature and unblemished completely ripe tomato fruits were used for the pathological test while those that were 30−60% ripe (pink) were used for the physiological tests of the effects of these pollutants on plant materials. The fruits were washed, and surface disinfected before use. Results of physiological test show that gasoline fuel emission delayed ripening of fruits as exposure time increased. In vitro tests showed that gasoline fuel emission treatment was most effective in preventing the spore germination of Rhizopus stolonifer and effectively inhibited germ tube elongation in the same fungus while gasoline fuel emission had little effect on the spore germination and germ tube elongation of Fusarium oxysporum. The completely ripe fruits inoculated with R. stolonifer and F. oxysporum separately before treatment with gasoline fuel emission and storage at 28oC and saturated relative humidity showed a decrease in rot severity caused by Rhizopus stolonifer as exposure to the gasoline fuel emission increased. Unwounded fruits inoculated with Fusarium oxysporum showed promotion of growth of the organism with exposure to emission while result on wounded tomato fruits showed that gasoline emission had little effect on the organism. This study has shown that gasoline fuel emission treatment has effect on the two tomato pathogens and postharvest rot development. Emission also had effect on further ripening of partially ripe tomato fruits.