Study on the effect of the chiral herbicide imazethapyr on flowering initiation in Arabidopsis thaliana

Non-target plants play a key role in maintaining ecological balance and biodiversity. Here, we studied the effect of the chiral herbicide imazethapyr (IM) on the flowering initiation of the non-target plant Arabidopsis thaliana and its underlying mechanism. Plants treated with R-IM initiated flowering earlier than those treated with S-IM. The herbicidally active R-IM had a much greater effect on various phytohormones than S-IM, and this effect increased with the concentration of R-IM. Before flowering, R-IM had a significant effect on the internal levels of 1-aminocyclopropane-1-carboxylic acid (ACC), indole-3-acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA3) in Arabidopsis plants, which indicated that it promoted the production of ACC, and high concentrations of R-IM also promoted IAA, ABA, and GA3. R-IM promoted ACC, IAA, and GA3 before and during flowering. High concentrations of R-IM strongly promoted IAA and inhibited GA3, and R-IM inhibited or promoted ACC depending on the concentrations applied. Thus, earlier flowering of Arabidopsis under R-IM treatment may be affected by phytohormone levels throughout the plant, and IAA, ACC, and GA3 likely have significant effects on flowering.