A bibliometric analysis of global research hotspots and progress on microplastics in soil‒plant systems.

Plastic pollution has become a global and persistent challenge, posing threats to ecosystems and organisms. In recent years, there has been a rapid increase in scientific research focused on understanding microplastics in the soil‒plant system. This surge is primarily driven by the direct impact of microplastics on agricultural productivity and their association with human activities. In this study, we conducted a comprehensive bibliometric analysis to provide an overview of the current research on microplastics in soil‒plant systems. We systematically analysed 192 articles and observed a significant rise in research interests since 2017. Notably, China has emerged as a leading contributor in terms of published papers, closely followed by Germany and the Netherlands. Through co-authorship network analysis, we identified 634 different institutions that participated in publishing papers in this field, with the Chinese Academy of Sciences having the most collaborations. In the co-occurrence keyword network, we identified four clusters focusing on the diversity of microplastics within the agroecosystem, transportation, and quantification of microplastics in soil, analysis of plastic contamination type and impact, and investigation of microplastic phytotoxicity. Furthermore, we identified ten research priorities, categorized into the effects of microplastics in "soil" and "plant". The research hotspots were found to be the effect of microplastics on soil physicochemical properties and the synergistic phytotoxicity of microplastics with other pollutants. Overall, this bibliometric analysis holds significant value, serving as an important reference point and offering valuable suggestions for future researchers in this rapidly advancing field.

Biochemical and transcriptomic responses of buckwheat to polyethylene microplastics.

The ubiquity of microplastic is widely recognized as pollution. Microplastic can affect the growth performances of plants. Buckwheat is a potential model crop to investigate plant responses to hazardous materials. Still, little is known about the response of buckwheat to microplastics. Thus, this study investigated the effect and uptake of polyethylene (PE) in buckwheat plant growth by monitoring the morphological and photosynthetic merits, antioxidant systems and transcriptome analysis of gene expression. Results confirmed that the impacts of PE on buckwheat growth were dose-dependent, while the highest concentration (80 mg/L) exposure elicited significantly negative responses of buckwheat. PE can invade buckwheat roots and locate in the vascular tissues. PE exposure disturbed the processes of carbon fixation and the synthesis of ATP from ADP + Pi in buckwheat leaves. The promotion of photosynthesis under PE exposure could generate extra energy for buckwheat leaves to activate antioxidant systems by increasing the antioxidant enzyme activities at an expense of morphological merits under microplastic stresses. Further in-depth study is warranted about figuring out the interactions between microplastics and biochemical responses (i.e., photosynthesis and antioxidant systems), which have great implications for deciphering the defense mechanism of buckwheat to microplastic stresses.