Soil metal(loid) pollution is a threat to ecological and environmental safety. The vegetation recovery in mining areas is of great significance for protecting soil resources. In this study, (1) we first gathered four types of soils to analyse their contamination degree, including tailings mud (TM), wasteland soil (TS) very near TM, as well as non-rhizosphere soils of pepper (PF) and maize (MF) in a farmland downstream from the TM (about 5 km). Geo-accumulation and potential ecological risk indices indicated that the soil samples were mainly polluted by antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and copper (Cu) to different degrees. Leachates of TM resulted in increased Sb, As, and Cd accumulation in TS. (2) Then, we sampled six local plants growing in the TS to assess the possibilities of using these plants as recovery vegetation in TS, of which Persicaria maackiana (Regel) Nakai ex T. Mori absorbed relatively high Sb concentrations in the leaves and roots. (3) After that, we collected rhizosphere soil and tissue samples from eight crops on the above farmland to assess their capacities as recovering vegetation of contaminated farmland soil, of which the fruits of maize accumulated the lowest concentrations of most monitored metal(loid)s (except for Pb). Further, we compared the differences in the bacterial community structure of MF, PF, TM, and TS to assess capacities of cultivating pepper and maize to improve soil microbial community structure. The MF displayed the best characteristics regarding the following attributes: (1) the highest concentrations of OMs and total P; (2) the highest OTU numbers and diversity of bacteria; and (3) the lowest abundance of bacteria with potentially pathogenic and stress-tolerant phenotypes.

Polygonatum cyrtonema Hua (PCH) is traditionally recognized as both an edible and medicinal food source. Its rhizomes contain numerous bioactive compounds, notably polysaccharides and flavonoids, which serve as key constituents in functional food development. However, the cultivation of PCH is often hindered by allelopathic effects, which diminish its quality and restrict its industrial application. To mitigate these allelopathic influences, three types of biochars derived from maize straw (MB), rice husk (RB), and tea stem (TB) were applied at concentrations of 0%, 2%, and 4%. Initially, the physicochemical properties of these biochars were characterized, followed by an evaluation of their impact on (1) the synthesis of quality-related components, secondary metabolites, and allelochemicals within PCH rhizomes and (2) the fundamental physicochemical properties and bacterial community structure of the PCH rhizosphere soil. The findings indicated that the application of 4% RB significantly enhanced the content of total polysaccharides by 48.5%, total flavonoids by 30.2%, total saponins by 28.6%, and total polyphenols by 18.3%, while concurrently reducing protein (PRO) and free amino acid (FAA) concentrations in the rhizomes. Non-targeted metabolomic analyses revealed that biochar amendments (1) upregulated metabolites involved in the citrate cycle and galactose metabolism pathways, thereby facilitating energy supply and precursors for polysaccharide biosynthesis; (2) downregulated metabolites involved in the arginine biosynthesis pathway, which is unfavorable for protein and amino acid synthesis; (3) decreased the abundance of six identified allelochemicals, including 5-hydroxy-L-tryptophan and andrographolide, with the most pronounced effect observed in the 4% TB treatment (T2); (4) improved soil physicochemical parameters such as pH, soil organic matter (SOM), total nitrogen (TN), and available potassium (AK); and (5) altered the rhizosphere bacterial community by enriching beneficial phyla, notably Myxococcota and Gemmatimonadota. These modifications in soil properties and bacterial community composition were closely associated with enhanced rhizome quality and a reduction in allelochemical accumulation. Collectively, the results of this study elucidate the potential mechanisms linking biochar application to allelopathy mitigation, optimization of soil microbial communities, and improvement of PCH rhizome quality. This research provides a theoretical basis for the production of high-quality PCH while concurrently minimizing allelochemical accumulation in its rhizomes.

Introduction: Pseudostellaria heterophylla (PSH) is a renowned medicinal and culinary plant. However, soil-related factors limiting in the improvement of its yield and quality in practice remain poorly understood. Methods: We sampled two PSH varieties and their associated rhizosphere soils from two sites in Ningde City, Fujian Province, China, including Chouling village (Z) and Wuyang village (W), to analyze the basic soil physicochemical properties, soil bacterial communities, and untargeted metabolomics of both soils and tuberous roots samples. Results: Our results showed that the rhizosphere soil at site Z had significantly higher concentrations of calcium (Ca), magnesium (Mg), manganese (Mn), available phosphorus (AP), and available potassium (AK), but a lower concentration of alkaline hydrolyzable nitrogen (AN). Soil AN and AK were identified as key determinants of bacterial community structure, showing negative and positive correlation with numerous microbial phyla and genera, respectively. Site Z exhibited higher abundances of functional bacterial phyla, including Desulfobacterota, Nitrospirota, and Elusimicrobiota, as well as dominant genera of Acidobacteriota. Amino acids and peptides (AAs) were the most abundant class of differential metabolites (DMs) in both the rhizosphere soil and tuberous roots of PSH. The accumulation of AAs in tuberous roots was positively correlated with soil pH, electrical conductivity (EC), and potassium (K) levels, but negatively correlated with AN. Furthermore, specific microbial taxa and soil DMs at site Z were positively associated with AA abundance in the tuberous roots. Discussion: These findings suggest that appropriate soil nitrogen levels coupled with relatively high potassium availability, pH, and EC conditions are conducive to AAs accumulation in PSH tuberous roots.

Zengcheng (ZC), a superior cultivar of Mesona chinensis Benth, is distinguished by its unique sensory attributes and exceptional phytochemical quality, rendering it the cultivar of choice for commercial production. In this investigation, we employed comprehensive targeted metabolomics to systematically delineate the volatile metabolome of ZC in comparison to three relevant counterparts grown under uniform field conditions and harvested at the same developmental stage. Our primary objectives were to (i) quantitatively characterize the metabolomic divergence between ZC and the comparative cultivars, and (ii) elucidate the molecular basis underlying ZC’s characteristic flavor signature. Through high-throughput gas chromatography–mass spectrometry (GC-MS) analysis, a total of 1767 volatile metabolites were confidently annotated, with terpenoids and esters identified as the predominant chemical classes. Notably, ZC exhibited significantly elevated levels of terpenoids, esters, and aldehydes, which collectively conferred an intensified green, sweet, herbal, and fruity aroma. Key discriminatory metabolites included geranyl formate and geranic acid (imparting a pronounced green note), which were identified as pivotal determinants of ZC’s unique flavor profile. These findings provide mechanistic insights into the biochemical pathways governing flavor development in M. chinensis Benth and establish a robust foundation for precision-breeding strategies aimed at enhancing sensory quality and developing elite cultivars.