The effect of heterocyclic compounds of isoxazolone series on the growth and development of wheat seedlings (Triticum aestivum L.)

Arylidenisoxazolones have been known since the second half of the 20th century and still retain their relevance as biologically active compounds and the basis for further transformations. Biological testing of synthetic heterocyclic compounds – 4-arylidene-3-methylisoxazol-5-ones, which differ in nature, position and number of substituents in the aryl fragment, was carried out: 4-(4-methoxybenzylidene)-3-methylisoxazol-5-one, 4- (4-chlorobenzylidene)-3-methylisoxazol-5-one, 4-(4-dimethylaminobenzylidene)-3-methylisoxazol-5-one, 4-(4-hydroxy-3-methoxybenzylidene)- 3-methylisoxazol-5-one, 4-(3,4-dimethoxybenzylidene)-3-methylisoxazol-5-one. The compounds were obtained at the Department of Organic and Bioorganic Chemistry of the Saratov National Research State University named after N.G. Chernyshevsky in order to identify the relationship between structure and biological action. The paper presents the characteristics of the tested compounds and a modified method for the synthesis of arylidenisoxazolones. Seedlings of spring soft wheat Triticum aestivum L. cv. Saratovskaya 36 served as test objects. To assess the physiological activity of the tested compounds, we used the seed germination index, analysis of the morphometric data of the seedling, the root-to-shoot ratio and the root index. The inhibitory effect of some compounds on seed germination has been established. The most pronounced effect was manifested during seed germination in a solution of 4-(4-hydroxy-3-methoxybenzylidene)-3-methylisoxazol-5-one at a concentration of 10-7M. No significant effect of isoxazolone derivatives on the growth of the first leaf of the test object was found. All tested 4-arylidene-3-methylisoxazol- 5-ones had a stimulating effect on the growth of the root system in length. The direct nature of the dependence of this effect on the concentration of a solution of 4-(4-chlorobenzylidene)-3-methylisoxazol-5-one and 4-(3,4-dimethoxybenzylidene)-3-methylisoxazol-5-one was determined. A positive effect of the tested compounds on the root-to-shoot ratio of seedlings was revealed (with the exception of 4-(4-dimethylaminobenzylidene)- 3-methylisoxazol-5-one). The root index of seedlings was determined and it was found that the presence of methoxyl groups has an inhibitory effect on the value of this indicator. Based on the data obtained, it can be concluded that 4-(4-dimethylaminobenzylidene)-3-methylisoxazol-5-one and 4-(4-chlorobenzylidene)-3-methylisoxazol-5-one are promising compounds for further research.