Relative efficacy of paclobutrazol, propiconazole and tetraconazole as stress protectants in wheat seedlings.

摘要

Wheat cv. Katepwa seeds were imbibed for 18 h in distilled water (control) or an aqueous solution of paclobutrazol, propiconazole or tetraconazole. Seeds were then air dried and sown in a greenhouse. After 10 days, one set of seedlings was allowed to continue growing under optimal conditions while other sets were exposed to heat stress, water stress or the herbicide paraquat. Compared with wheat leaves from plants grown under optimal conditions, heat stress decreased shoot fresh weight, fluorescence values and chlorophyll levels, and increased electrolyte leakage. All symptoms of damage were alleviated by the triazoles, with paclobutrazol being the most effective. Similar trends were found under water stress, where seedlings treated with paclobutrazol had the highest percentage survival and the most shoot regrowth upon rewatering. Paclobutrazol was also the best triazole in protecting wheat leaves from damage caused by paraquat, a free radical generator.