Spatially Resolved Investigation of Herbicide-Safener Interaction in Maize (Zea mays L.) by MALDI-Imaging Mass Spectrometry.

Monitoring agrochemical distribution within plant tissues delivers significant insights into the adsorption, distribution, metabolism, and elimination of agrochemicals. Detection and imaging of the safener cyprosulfamide (CSA) and the herbicide thiencarbazone-methyl (TCM) after micro-droplet application on the surface of maize leaves (Zea mays L.) have been achieved using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). The agrochemicals were deposited onto the adaxial surface of maize leaves on growing plants, and their uptake, distribution, and metabolism were investigated at four timepoints (3 h, 24 h, 4 days, and 7 days) to assess the influence of CSA treatment on TCM metabolism. MALDI MSI visualized significant changes for the metabolism of TCM after 24 h. Although TCM metabolism was detected neither in the control without the safener nor in the approach with CSA on the second leaf, the co-application on the same leaf showed significant metabolism of the herbicide by detecting the metabolite N-demethylated TCM. These findings suggest that safener protection against herbicide injury is a rapid process in which CSA and TCM need to be present in the same tissues. This study showcases the use of MALDI MSI to visualize and analyze indirect interactions of two substances in planta.

Anxiolytic and antidepressant effects of Ziziphus mucronata hydromethanolic extract in male rats exposed to unpredictable chronic mild stress: Possible mechanisms of actions.

ETHNOPHARMACOLOGICAL RELEVANCE: Ziziphus mucronata (ZM) is used traditionally in the treatment of mood and depression. However, no existing scientific data is confirming this traditional claim. AIM OF THE STUDY: The present study was planned to investigate the anxiolytic and antidepressant-like effects of this plant in a stressed-induced depression model in rats. MATERIALS AND METHODS: Depressive-like behaviors were induced by exposing rats to different stress paradigms daily for 30 days. A sucrose preference test was performed to assess anhedonia in rats. Anxiety and depression-related behavior were assessed. The oxidative parameters (lipid peroxidation, SOD and catalase activities) were evaluated. Pindolol and Flumazenil were also used to assess the mechanism of action of ZM extract. RESULTS: The results showed that chronic administration of ZM (150, 300, and 600 mg/kg, p.o., 30 days) and imipramine treatment (20 mg/kg, p.o, 30 days) remarkably (P < 0.05) reversed the UCMS-induced behavioral changes observed in stress vehicle treated rats by reducing sucrose preference, decreased the immobility period in the FST and latency in NSF. Besides, ZM (300 and 600 mg/kg, p.o., 30 days) raised the percentages of time spent and number of open arms entries as well as the number of transitions. Also, ZM (300 mg/kg, (P < 0.05) decreased lipid peroxidation and increased both SOD and catalase activities (300 and 600 mg/kg, (P < 0.05)). These aforementioned behavioral indices were also completely nullified by pindolol a ß-adrenoceptors blocker and 5-HT 1A/1B receptor antagonist but not by flumazenil, a benzodiazepine receptors antagonist. CONCLUSION: ZM improved symptoms of anxiety and depression in behavioral despair paradigm in chronically stressed rats. The observed effects could be due to its capacities to restore the antioxidant status, and probably the modulation of monoamines transmissions.

Metabolism and spatial distribution of metalaxyl in tomato plants grown under hydroponic conditions.

Knowledge about translocation of plant protection products (PPP's) in plants is important to understand the uptake via the root system. Here we report the combination of analysis of tissue extracts by LC-HRMSn, autoradiography of 14C-labeled compounds and MALDI-MSI, which combine qualitative and quantitative information of chemical composition and the spatial distribution of PPP's and their metabolites in situ. Therefore, the uptake of the phenylamide fungicide metalaxyl was studied in tomato plants (Solanum lycopersicum) using a hydroponic system. The plants have been cultivated in perlite until the two-leaf stage and were transferred into the hydroponic test system afterwards. The radioactive labeled fungicide was readily taken up by the roots during the normal water consumption and radioactivity was translocated uniformly to the aboveground part of the tomato plants, while only small proportion of the applied radioactivity were observed in the roots. The distribution of metalaxyl after the plant uptake experiment in the primary roots where analyzed by a transversal tissue section in the zone of maturation. Metalaxyl is mainly localized in root xylem and in cortex located at the epidermis. With LC-HRMSn and radiochemical analyses of stem and leaf, no parent compound was detectable. Four polar metabolites were the main identified components of the residue and could be visualized by MALDI-imaging mass spectrometry. With these results we could show, that the fungicide metalaxyl is taken up by the plant via the roots during the regular water consumption and transported to xylem.