AN ONION (ALLIUM CEPA L.) AS A TEST PLANT

Phytotesting has long been used to determine the quality of seeds, agricultural soil fertility, in biomedical research, and recently in the field of environmental protection to assess the ecological quality of natural environment (water, soil) in phytotesting of toxicants. Various plant representatives are used as model test organisms, in particular, onion (Allium cepa L.) is considered as a standard test plant for the determination of toxicants. The purpose of the work is to generalize methodological approaches of using onion (Allium cepa L.) in phytotesting of toxicants. Methodology. During the research, the following methods were used: 1) general scientific methods (methods of theoretical research of available information); 2) analytical and generalized methods (for the analysis of scientific and literature sources on the given problem); 3) empirical (for accumulating facts); 4) methods of argumentation (to prove one’s own judgments). Scientific novelty - methodical approaches of using onion in phytotesting of toxicants are summarized, formulas for calculating phytotoxic indices (root length index, phytotoxic effect of solutions, toxicity index of solutions for each test function, average toxicity index of the tested solutions) are presented. Conclusions - phytotesting is a commonly used method of assessing the quality of natural environment (water, soil) which is based on the sensitivity of plants to external chemical influences and is reflected in growth and morphological characteristics. The standard test plant for the determination of toxicant influence is the onion (Allium cepa), which can be used both in the growth test and in the Allium-test. The most sensitive characteristics of onion are the mitotic activity of the apical meristem cells and the frequency of cells with chromosomal aberrations.