Физиологические эффекты действия на растения фунгицидов триазольной природы

This study is focused on examination of crown dehydrin content during the overwintering and the spring dehardening periods in the three Poaceae family winter plants: rye, wheat, and triticale. Frost resistance of seedlings in the laboratory and field conditions were compared. Immunoblotting demonstrated that winter wheat and winter triticale differ from winter rye based on their dehydrin qualitative content. Unlike wheat and triticale, rye lacks a protein with a molecular mass of 55.3 kDa. Winter wheat contains a polypeptide with a molecular mass of 29 kDa in autumn, but lacks it in winter compared with triticale. Comparison of the dehydrin spectra from the three winter crops suggests a relationship between the synthesis of dehydrins with molecular masses of 29 and 55.3 kDa and the frost resistance of the plant species.

1, 2, 4-triazole derivatives, including tebuconazole, have been reported to show positive physiological effects in cereals apart from fungicidal activity and to increase plants’ tolerance against temperature stress. This study investigates the mechanisms of increasing frost resistance of etiolated winter wheat (Triticum aestivum L., “Irkutskaya” variety) seedlings by tebuconazole-based seed dresser “Bunker” (1.5 μL g⁻¹ of seeds) and tebuconazole (30 μg g⁻¹ of seeds). To identify ABA-dependent and ABA-independent pathways of frost resistance, we used fluridone (FLD, 5 mg L⁻¹), an inhibitor of endogenous abscisic acid (ABA) synthesis. FLD effectively inhibited the accumulation of carotenoids in the shoots and prevented the formation of carotenoids caused by the “Bunker” and tebuconazole. In non-hardened seedlings, FLD stimulated coleoptile and first leaf growth, but did not suppress the growth inhibitory effects of “Bunker” and tebuconazole. In shoots of hardened seedlings, FLD reduced the retarding effect of tebuconazole. Regardless of seedling age, temperature, and the protectant treatment, FLD had no effect on the sugar content in the shoots. FLD did not essentially influence frost resistance induced by “Bunker” and tebuconazole in cold-hardened seedlings. Fluridone increased H₂O₂ content and guaiacol peroxidase activity under control conditions (both with tebuconazole and without tebuconazole) and during cold hardening (in seedlings from seeds treated with tebuconazole). ABA levels in cold-hardened seedlings treated with FLD alone, tebuconazole alone, or a combination of the two were two to three times lower than in untreated hardened seedlings. Changes in indole-3-acetic and salicylic acids in response to FLD and tebuconazole treatment indicate complex interactions with signaling cellular systems. Our results suggest that tebuconazole activates ABA-independent pathways more strongly than ABA-dependent pathways in enhancing frost resistance. The potential mechanisms of tebuconazole action in plant cells are discussed.

A field experiment was conducted at an agro-ecological station (53 ° 33‘58.75 “N and 102 ° 35‘23.90” E) of the Siberian Institute of Plant Physiology and Biochemistry on gray forest medium loam soil. Winter rye (family 6) and winter triticale (No. 430-6002) were sown in 4 terms with a 10-day interval (10, 20, 30 August and 10 September) in three replications. The results of the two-year studies show that the winter crops included in the experiment had a higher (higher than 5 t/ha) and more stable yield between the years with the planting dates held on August 20, 30 and September 10 for rye and August 30 and September 10 for triticale. Earlier sowing time contributed to intensive tillering, strong growth, which led to the plant death and lower yields.