Elena Bonciu

Cytogenetic effects induced by the fungicide Royal Flo to maize (Zea mays L.)

Abstract The present study investigates the cytogenetic effects of the fungicide Royal Flo on mitotic cell division in maize (Zea mays L.) root cells. The maize grains were treated with various fungicide concentrations (50, 70, and 80%) for 20, 24 and 48 h exposure times. The results obtained indicate that the fungicide Royal Flo had some cytogenetic effects, by reducing the mitotic index and inducing various cytologic and chromosomal anomalies. These effects manifested differently, their intensity being proportional to the concentration and exposure time. The most frequent chromosomal anomalies were bridges, fragments and binucleated cells, but sticky chromosomes, rings chromosomes and cells with a micronucleus have also been seen. This study proves that the fungicide Royal Flo, even when administered in smaller quantities than generally recommended, reduces the germination and the mitotic index of maize cells and induces a large number of chromosomal anomalies, which suggests its toxic, mutagenic potential. Consequently, we should identify the optimal concentrations for each agricultural species, so that the efficacy of the fungicide does not diminish and, at the same time, its cyto-genotoxic potential is kept low.

The allelopathic, cytotoxic and genotoxic effect of Ambrosia artemisiifolia on the germination and root meristems of Zea mays

Abstract The problem of the invasion of the invasive species Ambrosia artemisiifolia L. is particularly important for Romania and other countries. Besides the fact that this species is a strong allergen, its presence in agricultural crops can aggravate the growth and development of plants, just like other weeds. The purpose of this study was to investigate the allelopathic effect of different concentrations of aqueous extracts obtained from the above-ground part (leaves and stems) and from the underground part (roots) of Ambrosia artemisiifolia on the germination and growth of Zea mays. Furthermore, for the first time, we have conducted a study of the cytotoxic and genotoxic effects of these extracts in meristematic cells of Zea mays. All extracts, and in particular 10% above-ground extract, significantly reduced the germination of the seeds and had a different effect on the growth of maize seedlings. Also, these extracts reduced the mitotic index (MI) and induced chromosomal alterations such as multinucleated cells, C-metaphases and sticky, ring, fragment, and bridge-type chromosomes, thus revealing a strong cytotoxic and genotoxic effect on maize.

Evaluation of the mitodepressive effect, chromosomal aberrations and nuclear abnormalities induced by urea fertilization in the meristematic tissues of Allium cepa L.

ABSTRACT Urea is one of the most commonly used nitrogen fertilizers in Romania. The cytogenetic objectives of this experience were the evaluation of the effects of cytotoxicity and genotoxicity induced by the action of urea applied in different concentrations (100, 500, 1000, 5000, 10,000 and 20,000 ppm) for 72 h on the meristematic tissues of Allium cepa L., a species very commonly used in cytotoxicity tests. The statistical analysis of the obtained results indicates that with the increase in urea concentration, mitotic activity is inhibited, while the chromosomal aberration rate in the cells in mitosis as well as the frequency of nuclear abnormalities in the interphase cells increases. From this point of view, the main chromosomal aberrations identified were stickiness, laggards and C-mitosis, while nuclear abnormalities were the appearance of a large number of binuclear and multinucleated cells, some with ghost nuclei. In addition, at concentrations of over 1000 ppm and especially at 10,000 and 20,000 ppm urea the presence of cells with one or more micronuclei (even with nine micronuclei) was signalled, indicating a strong clastogenic potential of urea. The results suggest caution in the use of urea, by applying small concentrations, within the environmental limits, for the protection of the environment, but also of humans and animals. The concentrations we recommend to reduce the risk of pollution are between 100 and 500 ppm urea. However, further investigation is needed to confirm these findings.

An evaluation for the standardization of the Allium cepa test as cytotoxicity and genotoxicity assay

ABSTRACT A general report on the use of the Allium test as cytotoxicological and genotoxicological assay is proposed, with particular emphasis about the standardization of the test in several common applications. The intraspecific variation in Allium cepa has been overlooked, as in most investigations no mention is made about origin and denomination of the onion cultivar used. A standardization of the used material would allow a better generalization of the results, since we cannot be sure that all cultivars would give the same response. A more frequent use of transmission electron microscopy (TEM) investigation is proposed. Even if relatively time consuming and not available in all laboratories, it may help to better understand the mechanism of cytotoxicity, since many morphological characters may appear similar but be arisen from different processes observable only with TEM. About statistical testing, tests other than chi-squared may be used in case of a lower amount of data. The most commonly used statistical tests are the parametric tests ANOVA and Student’s t, and the non-parametric tests Kruskal–Wallis and Mann–Whitney U, for analysis of variance. Tests should be used also to assess the minimal sample dimension for obtaining significance, since data collection (microscope observation) appears to be one of the main bottle necks of the test. Also the use of the Allium test for testing liposomes and other nanovectors for drug delivery is proposed, in order to assess the cytotoxicity of these types of medium and the possible increase in cytotoxicity of the associated drug.