土壤铜(Cu)污染是三七种植区严重的环境风险。然而,铜对该地区土壤微生物代谢和养分循环的影响尚不清楚。因此,本研究利用BiologECO平板和酶化学计量学方法研究了外源Cu(对照:0mg·kg-1;Cu100:100mg·kg-1;Cu400:400mg·kg-1;和Cu600:600mg·kg-1)对三七土壤中土壤微生物代谢功能和养分限制的影响。结果表明,Cu100显著增加了土壤有机碳(SOC),总磷(TP),土壤C:N,微生物生物量碳(MBC),和微生物生物量氮(MBN)9.89%,15.65%,17.91%,61.87%,比对照高出90.56%,分别。此外,碳水化合物的碳源利用率,氨基酸,Cu100的两亲性化合物也增加了7.16%,25.47%,和84.68%,分别,与对照相比。β-1,4-葡萄糖苷酶的活性,纤维二糖酶,亮氨酸氨基肽酶,β-1,4-N-乙酰氨基葡萄糖苷酶,随着Cu浓度的增加,磷酸酶显著降低。土壤酶化学计量表明,所有处理均受氮限制(矢量角度<45°;19.045-22.081)。Cu600导致最低的碳限制(1.798)和最高的碳利用效率(CUE:0.267)。PLS-SEM模型还表明,MBC,MBN,MBP,和微生物多样性对碳氮限制(0.654和0.424)有积极影响。土壤碳,氮,磷,化学计量比,MBC,MBN,MBP对CUE有积极影响(0.527和0.589)。微生物多样性指数显著负面影响CUE(-1.490)。多元线性逐步回归分析表明,CUE主要受MBC的影响,AP,C:P,和LAP。因此,三七土壤在低Cu浓度下有利于土壤微生物碳和氮限制。明确Cu胁迫下微生物的代谢活性和营养状况,可为实现我国2035年全面有效的金属环境风险管控政策提供理论依据。
Soil copper (Cu) pollution is a serious environmental risk in the Panax notoginseng planting area. However, the effect of Cu on soil microbial metabolism and nutrient cycling in this area remains unknown. Therefore, Biolog ECO-plate and enzyme stoichiometry methods were utilized in this study to investigate the impact of exogenous Cu (control: 0 mg·kg-1; Cu100: 100 mg·kg-1; Cu400: 400 mg·kg-1; and Cu600: 600 mg·kg-1) on the metabolic function of soil microbial and nutrient limitation in the P. notoginseng soil. The results indicated that Cu100 significantly increased soil organic carbon (SOC), total phosphorus (TP), soil C:N, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) 9.89%, 15.65%, 17.91%, 61.87%, and 90.56% higher than the control, respectively. Moreover, the carbon source utilization ratio of carbohydrates, amino acids, and amphiphilic compounds of Cu100 also increased by 7.16%, 25.47%, and 84.68%, respectively, compared with the control. The activities of β-1,4-glucosidase, cellobiohyrolase, leucine amino peptidase, β-1,4-N-acetylglucosaminidase, and phosphatase significantly decreased with increasing Cu concentration. Soil enzyme stoichiometry showed that all treatments were limited by nitrogen (vector angle < 45°; 19.045-22.081). Cu600 led to the lowest carbon limitation (1.798) and highest carbon use efficiency (CUE:0.267). The PLS-SEM model also showed that MBC, MBN, MBP, and microbial diversity positively affected carbon and nitrogen limitation (0.654 and 0.424). Soil carbon, nitrogen, phosphorus, stoichiometric ratio, MBC, MBN, and MBP positively affected CUE (0.527 and 0.589). The microbial diversity index significantly negatively affected CUE (-1.490). Multiple linear stepwise regression analyses showed that CUE was mainly influenced by MBC, AP, C:P, and LAP. Thus, P. notoginseng soil can benefit soil microbial carbon and nitrogen limitations at low Cu concentrations. Clarifying the metabolic activity and nutritional status of microorganisms under Cu stress can provide some theoretical basis for realizing China\'s comprehensive and effective management and control policies for environmental risks from metals by 2035.