Antioxidants and secondary metabolites changes in stomata and pollens of invasive alien plant Lantana camara.
Lantana camara is a noxious and invasive weed from family Verbenaceae, native to tropical America, but now widespread in many countries. However, there has been little research on its biochemical traits that confer this plant to withstand abiotic stresses. Therefore, to get insight about the biochemical basis of invasiveness of Lantana, in the present study, the abiotic stress induced changes in reactive oxygen species like hydrogen peroxide (H2O2), ROS scavenging enzymes and secondary metabolites were studied in stomata and pollens of Lantana camara. Lipid peroxidation/malondialdehyde showed an increase level in plant leaves under stress conditions. Significant increase in H2O2 was also observed in stomata and pollens under heat and cold stress conditions. Further, heat, cold, ABA and H2O2 treatments resulted in significant decrease in stomatal aperture. Consequently, width and length of stomata in stress conditions reduced and increased, respectively. In situ activities of various antioxidants viz.: glutathione, thioredoxin reductase, NADPH oxidase, catalase, superoxide dismutase, peroxidase, monodehydroascorbate reductase increased profoundly under cold and heat stress as compared to control in stomata and pollens. Similarly, levels of secondary metabolites (lignin, lipids, suberin, cellulose, hemicellulose, callose) increased in stomata and pollens under adverse abiotic stress conditions as compared to control conditions. So, elevated levels of ROS scavenging enzymes and various secondary metabolites under harsh and stressful conditions suggest their role in minimising the level of oxidative stress. At last, it can be inferred from the results that Lantana camara has the potential to cope with the different abiotic stresses by accumulating abiotic stress-related metabolites.