Spectroscopic contribution to glyphosate toxicity profile and the remedial effects of Momordica charantia

In this study, the glyphosate toxicity and the toxicity-reducing role of bitter melon extract (Bmex) (Momordica charantia L.) were investigated in Allium cepa L. test material. The toxicity of glyphosate and protective role of Bmex were investigated with the help of physiological (germination, root elongation and weight gain), cytogenetic (mitotic index-MI, micronucleus-MN and chromosomal abnormalities-CAs), biochemical (malondialdehyde-MDA, superoxide dismutase-SOD and catalase-CAT) and anatomical (root meristem cell damage) parameters. The genotoxicity mechanism of glyphosate was elucidated by spectral analysis. A. cepa bulbs were divided into six groups as one control and five applications. Tap water was applied to the bulbs in the control group for 72 h. Glyphosate (500 mg/L) and two different doses of Bmex (350 and 700 mg/L) were applied to the bulbs in the treatment group for 72 h. At the end of the period, the germinated bulbs were prepared for experimental analyses, measurements and observations by applying routine preparation procedures. As a result, glyphosate administration caused a significant (p < 0.05) decrease in all selected physiological parameter values, and significant (p < 0.05) increases in the number of cytogenetic parameters (except MI), the levels of biochemical parameters and the severity of anatomical damage. Glyphosate promoted CAs such as fragment, sticky chromosome, bridge and unequal distribution of chromatin in root tip meristem cells. By spectral analysis, it was determined that glyphosate interacts directly with DNA and causes genotoxicity. It also caused anatomical damages such as epidermis cell damage, cortex cell damage, flattened cell nucleus, binuclear cell and irregular vascular tissue in root tip meristem cells. Co-administration of glyphosate with Bmex at two different doses (350 and 700 mg/L) reduced the toxicity of glyphosate and led to significant (p < 0.05) improvements in the values of all parameters examined. It was determined that this improvement was even more pronounced at 700 mg/L dose of Bmex. As a result, it was determined that glyphosate herbicide caused multi-dimensional toxicity in A. cepa test material, and Bmex reduced the effects of this toxicity due to its antioxidant properties. Therefore, glyphosate dose ranges need to be reconsidered, especially considering non-target organisms in agricultural applications. In addition, antioxidant products such as Bmex should be included in the daily diet in order to reduce the toxic effects of environmental agents such as pesticides.

Can low doses of glyphosate stimulate common bean growth?

Plant growth can be stimulated by low doses of glyphosate. The objective of this work was to evaluate the effect of low doses of glyphosate and sowing season on the growth of the early cycle common bean. Two experiments were conducted in the field, the first in the winter and the second in the wet season, with the early cycle common bean cultivar IAC Imperador. The experimental design was a randomized complete block design, consisting of low doses of glyphosate applied on phenological stage V4, with four replications. Environmental conditions, such as air temperature, interfered in the early cycle common bean response to low doses of glyphosate. In the winter season, a dose of 36 g a.e. ha-1 promoted growth in the common bean, and a dose of 7.2 g a.e. ha-1 improved the harvest index. In the wet season, there was no growth stimulus, and the harvest index increased with a dose of 36 g a.e. ha-1. The harvest index was the only characteristic improved in both seasons, but with different doses. Our study indicates that growth characteristics of early cycle common bean are stimulated by low doses of glyphosate, but this response is dependent on the growing environment.