Phosphorus (P) availability influences the spatial distribution of carbon (C)-cycling enzyme activities in the rhizosphere through its effects on plant growth and microbial activity. However, the influence of P availability on the spatial patterns of C and P hydrolase activities remains unclear in the rhizosphere of Maize (Zea mays L.) and narrow-leaf lupine (Lupinus angustifolius L.), which exhibit contrasting P deficiency adaptation and acquisition strategies. This study analyzed the spatial patterns of C and P hydrolase activities through zymography and correlated them with bacterial community structure in maize and lupine rhizospheres. Under P-deficient conditions, maize exhibited severe growth restriction while demonstrating a 2.2–9.6-fold increase in root exudation compared to P-sufficient conditions. The enhanced exudation under P deficiency promoted r-strategist bacterial proliferation (e.g., Ktedonobacteria and Xanthomonadales) while reducing K-strategist abundance (Actinobacteriota, Chloroflexia, and Alphaproteobacteria). Maize rhizosphere enzyme activities and hotspot areas demonstrated positive correlation with K-strategist abundance and negative correlation with r-strategist abundance. P-sufficient maize exhibited 15–550% higher C- and P-cycle-related enzyme activity and hotspot areas, attributed to its enhanced root system and predominance of K-strategists with superior enzyme synthesis capabilities. Lupine demonstrated superior P deficiency adaptation, producing 2–19 times more DOC and organic acids than maize. Consequently, lupine showed no significant alterations in enzyme activity, hotspot areas, or bacterial community composition in response to P availability. These findings demonstrate that plant-specific P deficiency adaptation mechanisms distinctly influence the spatial distribution of C-cycling enzyme activity and bacterial community structure in the rhizosphere.

Moso bamboo (Phyllostachys Pubescens) expansion into adjacent forests has been widely reported to affect plant diversity and its association with mycorrhizal fungi in subtropical China, which will likely have significant impacts on soil respiration. However, there is still limited information on how Moso bamboo expansion changes soil respiration components and their linkage with microbial community composition and activity. Based on a mesh exclusion method, soil respirations derived from roots, arbuscular mycorrhizal (AM) mycelium, and free-living microbes were investigated in a pure Moso bamboo forest (expanded), an adjacent broadleaved forest (non-expanded), and a mixed bamboo-broadleaved forest (expanding). Our results showed that bamboo expansion decreased the cumulative CO₂ effluxes from total soil respiration, root respiration and soil heterotrophic respiration (by 19.01%, 30.34%, and 29.92% on average), whereas increased those from AM mycelium (by 78.67% in comparison with the broadleaved forests). Bamboo expansion significantly decreased soil organic carbon (C) content, bacterial and fungal abundances, and enzyme activities involved in C, N and P cycling whereas enhanced the interactive relationships among bacterial communities. In contrast, the ingrowth of AM mycelium increased the activities of β-glucosidase and N-acetyl-β-glucosaminidase and decreased the interactive relationships among bacterial communities. Changes in soil heterotrophic respiration and AM mycelium respiration had positive correlations with soil enzyme activities and fungal abundances. In summary, our findings suggest that bamboo expansion decreased soil heterotrophic respiration by decreasing soil microbial activity but increased the contribution of AM mycelial respiration to soil C efflux, which may potentially increase soil C loss from AM mycelial pathway.