Exploration the homeostasis of signaling molecules in monocotyledonous crops with different CuO nanoparticle tolerance

Copper is an essential microelement that is indispensable for plant growth and development. The use of copper oxide nanoparticles (CuO NPs) in industry and agriculture has also increased because of their beneficial prop- erties. However, excess amounts of CuO NPs may negatively affect the growth of monocotyledonous plant species, primarily through the generation of reactive oxygen species, which results in oxidative stress. Despite their increasingly widespread use, little is known regarding the signaling processes responsible for the effects of CuO NPs on the growth of monocotyledonous crops, or their impact on the homeostasis of reactive nitrogen species, hydrogen sulfide, and protein tyrosine nitration. In this study, the concentration of CuO NP that inhibits 50% of root growth was determined using sorghum, wheat, rye, and triticale as model plant species, and the NP-induced stress response and the balance of reactive molecules were assessed. Based on the effective concentration of CuO NP, wheat, rye, and triticale were more tolerant compared with sorghum, and entirely different response mechanisms in the homeostasis of reactive oxygen, nitrogen and sulfur species were observed. For the sensitive sorghum roots, the amount of reactive molecules was not significantly altered, whereas a significant increase in protein tyrosine nitration indicated a severely stressful state caused by CuO NPs. In contrast, the amount of reactive molecules increased significantly in the roots of the relatively tolerant species, and while the appearance of lipid peroxidation indicated oxidative stress, different changes in protein tyrosine nitration was associated with tolerance. The significant CuO NP- induced rise of endogenous H2S content in the root tips may be partly responsible for the relative tolerance of wheat, rye, and triticale compared with sorghum. CuO NP stress induced distinct modifications in the root tip cell walls of the examined species, where lignification was observed in the relatively sensitive sorghum, while in the tolerant species only callose deposition was detected. Overall, our results demonstrate that while mono- cotyledonous species with different CuO NP sensitivities may exhibit similar growth responses, the underlying changes in the dynamics of reactive molecules influence their tolerance

Indirect effects of COVID-19 on the environment: How plastic contamination from disposable surgical masks affect early development of plants

Personal protective equipment, used extensively during the COVID-19 pandemic, heavily burdened the environment due to improper waste management. Owing to their fibrous structure, layered non-woven polypropylene (PP) disposable masks release secondary fragments at a much higher rate than other plastic waste types, thus, posing a barely understood new form of ecological hazard. Here we show that PP mask fragments of different sizes induce morphogenic responses in plants during their early development. Using in vitro systems and soil-filled rhizotrons, we found that several PP mask treatments modified the root growth of Brassica napus (L.) regardless of the experimental system. The environment around the root and mask fragments seemed to influence the effect of PP fabric fragment contamination on early root growth. In soil, primary root length was clearly inhibited by larger PP mask fragments at 1 % concentration, while the two smallest sizes of applied mask fragments caused distinct, concentration-dependent changes in the lateral root numbers. Our results indicate that PP can act as a stressor: contamination by PP surgical masks affects plant growth and hence, warrants attention. Further investigations regarding the effects of plastic pollution on plant-soil interactions involving various soil types are urgently needed