IMPROVEMENT OF UNICONAZOLE-INDUCED PROTECTION IN WHEAT SEEDLINGS

Uniconazole [(E)-(p-chlorophenyl)-4, 4-dimethyl-2-(1,2,4-triazol-1 -yl)-1 -penten-3-ol] belongs to a group of triazoles which, in addition to their fungitoxic and plant growth-regulating (PGR) properties, protect plants from various stresses. Compared to the conventional methods of treatment which include seed, soil drench, and foliar spray, the present study shows that a convenient and simple method of administering the chemical is by imbibing wheat (Triticum aestivum L. cv. Frederick) seeds in uniconazole solution for 20 h. The soaked seeds can be stored after air drying and germinated when desired. Addition of potassium to the uniconazole solution and exposure of the seeds to 40°C for the last 2 h during the imbibition period further enhanced the PGR effectiveness and improved the efficacy of the uniconazole-induced protection against drought and low- and high-temperature stresses. Uniconazole increased both carotenoid and chlorophyll levels and in combination with KCl, the increase in chlorophyll was more than twice that of the controls. The combination pretreatment of the imbibed seeds used in this study not only magnifies the protective and PGR effects of uniconazole but also supports the concept of acclimation and cross-tolerance. © 1990 Springer-Verlag New York Inc.