Effects of Glyphosate Herbicide on Photosynthetic Pigments and Antioxidant Enzyme Activities in Corn (Zea mays L.) and Wheat (Triticum aestivum L.) Varieties

Abstract

ARTICLE INFOIn this study, it was determined that phytotoxic levels of glyphosate herbicide that will be banned in Europe may be at on wheat and corn plants. Biochemical responses due to the toxic effect of glyphosate at different concentrations were determined in corn (Zea mays L. cv. Ada 523) and wheat (Tritucum aestivum L. cv. Halis) varieties. For wheat and corn varieties, 4 different doses (0, 100, 500 and 1000 μM) of the herbicide were applied to 1-week-old and 15-day-old plants. Hydroponic medium was used for all applications on plants. According to the results obtained; the toxic effect created by glyphosate increased the destruction of pigment in the leaves and significant decreases were detected. While GST, SOD and CAT activities increased in all concentrations of 1-week-old plants treated with glyphosate, only GST activity decreased at 100 μM concentration of wheat leaf and corn root. SOD and CAT activities were increased in 15-day-old wheat and corn plants treated with glyphosate. Only SOD activity decreased in the root part of the maize plant. GST activity was increased in the roots and leaves of the maize plant, while it decreased in wheat leaves and roots at a concentration of 100 μM. As a result, glyphosate was found to be effective at very low concentrations in wheat and corn regardless of age. It was also revealed that 1-week-old corn and wheat crops inhibit more phytotoxic effects than these 15-day-old plants. In other words, young plants were found to be more resistant.

Evaluation of chlorophyll content and membrane stability under oxidative stress induced by glyphosate herbicide as indicators of drought tolerance in some advanced durum wheat (Triticum durum L.) lines: in vitro study

“…It's also well known that a decrease in the chlorophyll content could be due to a decrease in the stomata aperture, aimed at limiting water losses by evaporation and by increased resistance to the entry of atmospheric CO 2 necessary for photosynthesis (Zhu et al, 2016;Enneb et al, 2020). Karabulut and Çanakcı (2021) showed that the oxidative stress created by glyphosate treatment caused decrease in chlorophyll (a+b). As well, Caglar et al (2011) analyzed the effects of the herbicide paraquat on chlorophyll content, observing that bread wheat varieties after paraquat herbicide treatment decreased chlorophyll content.…”

Lipid Peroxidation, Proline Content and Soluble Sugars as indicators of Oxidative Stress Tolerance in Some Advanced Durum Wheat Lines (Triticum durum Desf.).

“…Tulkova and Kabashnikova (2021) found that lipid peroxidation refers to a series of free radical reactions in unsaturated fatty acids and that an increase in lipid peroxidation activity under prolonged stress indicates a decline in the scavenging ability within plant cells. Karabulut and Canakcı (2021) analyzed the effects of the herbicide glyphosate in maize and wheat varieties and observed that plants produce antioxidant defense systems, including enzymatic and nonenzymatic methods, as a result of ROS accumulation. Thus, as the amount of ROS increases, the level of MDA begins to accumulate.…”