RESUMEN
Fomesafen is an herbicide used in soybean production, and sugar beet is a sensitive crop to fomesafen. When the herbicide is sprayed in the field, it is easy to cause floating and depositing on non-target crops, resulting in crop poisoning and reducing yield. There are few on the phenomenon and mechanism of fomesafen herbicide drift on sugar beet. There are few reports on the phenomenon and mechanism of ether herbicide migration on phytotoxicity of sugar beet. Therefore, in this experiment, indoor potted plants were used to simulate the dose of fomesafen drift deposited on sugar beet in the field to study the effects of fomesafen on the growth, photosynthetic system, and physiological indexes of seedlings for sugar beet were studied. The results showed that fomesafen at the dose of 225 g a.i. ha-1 significantly inhibited the plant height, root length, and biomass of sugar beet. Compared with the control, the net photosynthetic rate, stoma conductance, transpiration rate, and total chlorophyll pigment content of leaves were reduced by 77.16%, 83.84%, 64.00%, and 28.13%, respectively. Treatment with a dose of 225 g a.i. ha-1 also damaged the photosynthetic system II of the leaves, lowering the performance index on absorption energy, maximum quantum yield and, the energy of electron transfer, causing photoinhibition and photodamage. In addition, fomesafen significantly increased the content of malondialdehyde and the activity of peroxidase in leaves of sugar beet, reducing the activities of superoxide dismutase and catalase. Overall, this study is helpful to understand the drift and deposition of fomesafen on sugar beet and to discuss the phytotoxicity risk and dose of fomesafen on the beet, as a result of controlling the dose of fomesafen sprayed in the field.