Study on toxicological effects of herbicide atrazine on alfalfa seedlings

Abstract

Atrazine is a pre and post seedling herbicide that selects internal absorption conduction. Due to its high efficacy, low dosage, wide herbicide spectrum, and long residual efficacy period, it has been rapidly and widely used and promoted. From a global perspective, atrazine is currently one of the most widely used herbicides. However, due to its extensive use, it has been found to cause pesticide damage in soil and the environment. In order to study the effects of different concentrations of atrazine on the growth and physiological effects of alfalfa seedlings, six different concentrations of atrazine (0, 0.1, 0.2, 0.4, 0.8, 1.6 mg/L) were used to treat alfalfa seedlings using the pre seedling soil treatment method after indoor sowing. The growth and chlorophyll, malondialdehyde (MDA) content of alfalfa seedlings were measured. Firstly, determine the effect of atrazine on the growth of alfalfa. As the concentration of atrazine treatment increased, compared with the variant without treatment, the length of the aboveground and underground parts showed a significant inhibitory effect. Under the 1.6 mg/L treatment, the length of the aboveground part decreased by 26.3 %, while the length of the underground part decreased by 39.5 %. At the same time, it was found that the dry weight of alfalfa also showed a significant decreasing trend. At the maximum treatment concentration, the dry weight of the aboveground and underground parts decreased by 20.0 % and 14.3 %, respectively, The residue of atrazine in soil affects the growth and development of plants. The main mechanism of action of atrazine is to inhibit photosynthesis and hinder carbohydrate and photochemical synthesis reactions, preventing normal plant growth. The experiment found that as the concentration increased, the chlorophyll content in alfalfa leaves gradually decreased. Compared with the variant without treatment the chlorophyll content decreased by 48.0 %. At a concentration of 1.6 mg/L, the chlorophyll content decreased by 20.9 % compared to alfalfa seedlings without treatment. At the same time, the TBARS determination results showed that the content of MDA was the highest at a concentration of 0.8 mg/L, which was 2.50 times higher than on the control. However, 1.6 mg/L is the lowest, only 4.32 times that of with the variant without treatment. Atrazine causes membrane lipid peroxidation in alfalfa seedlings, leading to increased lipid permeability and toxicity at high concentrations. Therefore, attention should be paid to controlling the concentration of atrazine in production, and the dosage should not be arbitrarily increased to avoid causing drug harm.