Physiological and biochemical responses of selected weed and crop species to the plant-based bioherbicide WeedLock

WeedLock is a broad-spectrum plant-based bioherbicide that is currently on the market as a ready-to-use formulation. In this study, we investigated the physiological and biochemical effects of WeedLock (672.75 L ha(-1)) on Ageratum conyzoides L., Eleusine indica (L.) Gaertn, Zea mays L., and Amaranthus gangeticus L. at four different time points. WeedLock caused significant reductions in chlorophyll pigment content and disrupted photosynthetic processes in all test plants. The greatest inhibition in photosynthesis was recorded in A. conyzoides at 24 h post-treatment with a 74.88% inhibition. Plants treated with WeedLock showed increased malondialdehyde (MDA) and proline production, which is indicative of phytotoxic stress. Remarkably, MDA contents of all treated plants increased by more than 100% in comparison to untreated. The activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) was elevated following treatment with WeedLock. Significant increases were observed in the SOD activity of A. conyzoides ranging from 69.66 to 118.24% from 6 to 72 h post-treatment. Our findings confirm that WeedLock disrupts the normal physiological and biochemical processes in plants following exposure and that its mode of action is associated with ROS (reactive oxygen species) production, similar to that of PPO (protoporphyrinogen oxidase) inhibitors, although specific site-of-action of this novel bioherbicide warrants further investigation.

Automated summary

This study investigated the physiological and biochemical effects of WeedLock, a broad-spectrum plant-based bioherbicide, on several plant species. The results showed that WeedLock caused significant reductions in chlorophyll content and disrupted photosynthesis in all tested plants. The treated plants exhibited increased production of malondialdehyde (MDA) and proline, indicating phytotoxic stress. The activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), was elevated following WeedLock treatment. These findings suggest that WeedLock disrupts normal physiological and biochemical processes in plants by producing reactive oxygen species (ROS), similar to the mode of action of protoporphyrinogen oxidase (PPO) inhibitors.