A comparison of the effects of acetochlor and fluoroglycofen on photosynthesis in grape leaves.

Herbicides are widely applied to control weeds in vineyards. However, they may also impose abiotic stresses on non-target crops. Paraquat, acetochlor and fluoroglycofen are three types of herbicides that are sprayed onto the soil beneath grapevines after the fruit develops. The study aimed to characterize the effects of these herbicides in combination on the photosynthetic characteristics and nutrition storage of grapevine branches throughout the growing season in Qufu, Shandong, China. The results were compared to control vines treated with artificial weeding. The application of the three herbicides reduced the net photosynthesis rate (Pn) in a dose-dependent manner. At the highest concentration, the Pn was reduced by 34.6% 35 d after treatment. By 58 d, there was no significant difference between the lower concentration of herbicides and artificial weeding. Moreover, the combination of herbicides with the highest concentration of each reduced the free amino acid and soluble protein content by 10.4% and 15.1%, respectively, in the fourth node branches. The results of the pot experiment showed that acetochlor and fluoroglycofen both reduced Pn in dose-dependent manner. Moreover, both herbicides also enhanced the malonaldehyde content and accelerated the production rate of superoxide anions in grapevines. Taken together, these results suggested that acetochlor and fluoroglycofen produced different degrees of poisonous effects in grapevines. We suggest that orchard management strategies should reduce the number and dosage of herbicides, or cover crops instead.