No abstract

No abstract

Solanum nigrum L. (Black nightshade), is one of the most troublesome weeds of summer crops such as corn, soybean, sunflower, etc. To study the effect of combined Castor oil as an adjuvant with different doses of Lumax (Mesotrion + S-metolacholor + Terbuthylazine) on the physiological behavior of Solanum nigrum L., a greenhouse experiment was conducted in randomized complete block design with four replications in agricultural faculty of the University of Tabriz in 2021. A foliar application of Lumax increased proline, malondialdehyde, and hydrogen peroxide concentrations and superoxide dismutase, catalase, and peroxidase activity. The content of protein and photosynthetic pigments (Chlorophyll a, b, and carotenoids) also decreased significantly by using Lumax herbicide. Applying castor oil in combination with Lumax intensifies oxidative stress and lipid peroxidation. Results showed that by increasing the herbicide doses in comparison with control (non-herbicide), Area, Fm, Fv, Fv/Fm, Fv/F0, Sm, Sm/Tfm, and Fv/F0 decreased 48.32%, 19.52%, 27.95%, 10.47%, 50.90%, 28.34%, 79.38%, and 50.90%, respectively and F0, F0/Fm increased 46.76% and 82.38%, respectively. Castor oil showed a synergistic effect on Lumax herbicide and enhanced its efficacy on Solanum nigrum. The presented results supported the view that by evaluating chlorophyll a fluorescence parameters, we would realize herbicide (alone or mixed with any adjacent) efficacy before the visual symptoms appear in the plant.

This study investigated the physiological characteristics and fluorescence reflection of Field bindweed after exposure to various doses of Clopyralid alone or in combination with salicylic acid. High doses of Clopyralid increased the concentrations of malondialdehyde and hydrogen peroxide, while decreased the activities of antioxidant enzymes. High concentrations of this herbicide also decreased the amount of protein and photosynthetic pigments but increased the proline content compared to the control treatments. Applying SA three days before Clopyralid spraying intensified oxidative stress and lipid peroxidation due to the disruption of the plant's hormonal balance as a result of the use of high dose of SA. PSII performance index was reduced under Clopyralid + SA. Field bindweed photosynthetic apparatus was further altered after SA application three days before Clopyralid spraying. This study highlighted that, for a better use of Clopyralid, the use of SA could be beneficial, not only for the herbicide efficacy against field bindweed weed, but also for the environment due to lower applied doses of herbicide.