Isoxadifen-ethyl can effectively alleviate nicosulfuron injury in the maize. However, the effects of safener isoxadifen-ethyl on detoxifying enzymes in maize is unknown. The individual and combined effects of the sulfonylurea herbicide nicosulfuron and the safener isoxadifen-ethyl on the growth and selected physiological processes of maize were evaluated. Bioassays showed that the EC₅₀ values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for maize cultivar Zhengdan958 were 18.87 and 249.28 mg kg^-1, respectively, and were 24.8 and 275.51 mg kg^-1, respectively, for Zhenghuangnuo No. 2 cultivar. Evaluations of the target enzyme of acetolactate synthase showed that the I₅₀ values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for the ALS of Zhengdan958 were 15.46 and 28.56 μmol L^-1, respectively, and were 0.57 and 2.17 μmol L^-1, respectively, for the acetolactate synthase of Zhenghuangnuo No. 2. The safener isoxadifen-ethyl significantly enhanced tolerance of maize to nicosulfuron. The enhanced tolerance of maize to nicosulfuron in the presence of the safener, coupled with the enhanced injury observed in the presence of piperonyl butoxide, 1-aminobenzotriazole, and malathion, suggested cytochrome P450 monooxygenases may be involved in metabolism of nicosulfuron. We proposed that isoxadifen-ethyl increases plant metabolism of nicosulfuron through non-P450-catalyzed routes or through P450 monooxygenases not inhibited by piperonyl butoxide, 1-aminobenzotriazole, and malathion. Isoxadifen-ethyl, at a rate of 33 mg kg^-1, completely reversed the effects of all doses (37.5–300 mg kg^-1) of nicosulfuron on both of the maize cultivars. When the two compounds were given simultaneously, isoxadifen-ethyl enhanced activity of glutathione S-transferases (GSTs) and acetolactate synthase activity in maize. The free acid 4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic was equally effective at inducing GSTs as the parent ester and appeared to be the active safener. GST induction in the maize Zhenghuangnuo No. 2 was faster than in Zhengdan 958.

Introduction: The residues of clomazone (Clo) can lead to phytotoxic symptoms such as foliar bleaching, reduced plant height, and decreased maize yields. Herbicide safener represent one of the most economically efficient strategies for mitigating herbicide-induced damage.Methods: In this study, various seed treatments were implemented, including the immersion of maize seeds in water (CK), immersion in Cyprosulfamide (CSA), soil supplemented with clomazone (ClO) and CSA+ClO, evaluated physiological indicators, chlorophyll content, and qRT-PCR analyses of the maize plants were evaluated under the different treatments.Results and discussion: The objective of this study was to investigate the impact of CSA on mitigating residual damage caused by Clo on maize and elucidate its mechanism. Compared to the CK, treatment with Clo resulted in significant inhibition of maize plant height, fresh weight, chlorophyll content, and carotenoid levels by 19.0%, 29.9%, 92.5%, and 86.3% respectively. On the other hand, under CSA+Clo treatment, milder inhibition was observed with reductions of only 9.4% in plant height and 7.2% in fresh weight, as well as decreases of 35.7% and 21.8% respectively in chlorophyll and carotenoid contents. The findings revealed that the application of CSA effectively mitigated the inhibitory effects of Clo residues on maize plant height, fresh weight, carotenoids and chlorophyll content. Additionally, the combination of CSA and Clo reduced MDA levels by 13.4%, increased SOD activity by 9.7% and GST activity by 26.7%, while elevating GSSG content by 31.3% compared to Clo alone, ultimately mitigating oxidative damage in maize plants. qRT-PCR analysis showed that the expression of five P450 genes (CYP72A5, CYP81A4, CYP81Q32, CYP81A9, CYP81A36), nine GST genes (GST30, GST31, GSTIV, GSTVI, GST21, GST7, GST37, GST25, IN2-1), and two UGT genes (UGT76C2, UGT83A1) significantly high increased by 6.74-, 10.27-, 4.98-, 10.56-, 25.67-, 16.70-, 46.92-,7.53-, 5.10-, 238.82-, 143.50-, 4.58-, 31.51-, 39.3-, 4.20-, 10.47-fold after CSA+Clo treatment compared to that in the Clo treatment. The pre-treatment of CSA led to the upregulation of five P450 genes, nine GST genes, and two UGT genes, which may be associated with the metabolism of Clo in maize. Overall, this study suggests that CSA could be effectively mitigates Clo residual damage by up-regulating detoxification-related genes, enhancing chlorophyll content and activities of antioxidant enzymes.

Volunteer wheat commonly occurs and spreads rapidly in the main wheat-producing areas of China, seriously impacting cultivated wheat production. Limited information is currently available regarding the adaptability and germination traits of volunteer wheat. Therefore, this study’s aim was to evaluate the effects of environmental conditions on the germination and emergence of volunteer wheat seeds through laboratory experiments. The results showed that the germination percentages and viability of volunteer wheat were significantly higher than those of cultivated wheat at a low temperature of 5 °C, and they were lower than those of cultivated wheat at high temperatures of above 30 °C. Compared to cultivated wheat, volunteer wheat was able to tolerate higher salinity and lower osmotic potential, especially long-dormancy volunteer wheat. The secondary germination ability of volunteer wheat was higher than that of cultivated wheat after water immersion. Furthermore, volunteer wheat could not emerge normally when the seeding depth was greater than 8 cm, and the emergence ability of the volunteer wheat was weaker than that of the cultivated wheats when the seeding depth was 4–8 cm, which indicates that the deep tillage of cultivated land could effectively prevent the spread of volunteer wheat. This study revealed differences in the germination characteristics of volunteer wheat and cultivated wheat under the influence of different environmental factors, which provides a basis for future studies concerning the control of volunteer wheat.