碳化石墨烯对朝天椒产量及其根区土壤养分和微生物群落结构的影响

【目的】探究碳化石墨烯对朝天椒产量、品质及其根区土壤养分、酶活性、重金属含量和微生物群落结构的影响，为石墨烯碳肥在辣椒高产高效优质栽培上的应用提供科学依据。【方法】以鲜用型朝天椒为研究对象，在基础施肥（CK）的基础上分别在定植后的朝天椒根区淋施0.07%石墨烯水溶液（A8处理）、0.35%石墨烯水溶液（B8处理）和1.75%石墨烯水溶液（C8处理），测定不同浓度石墨烯处理的朝天椒果实产量、营养指标和不同器官中重金属含量，以及朝天椒根区土壤养分、酶活性和重金属含量，分析不同浓度石墨烯处理的土壤微生物群落结构。【结果】不同浓度石墨烯处理对朝天椒的产量和品质存在一定影响，其中B8处理的产量、维生素C和辣椒素含量分别较CK显著增加6.40%、25.27%和20.45%（P<0.05，下同）；蛋白质含量无显著变化（P>0.05，下同），可溶性糖含量显著减少，而硝酸盐含量显著增加。各处理的朝天椒根区土壤全磷、全氮、全钾和土壤水解性氮含量无显著差异，但CK的速效磷和速效钾含量高于或显著高于各石墨烯处理；B8处理的有机质含量略高于CK，A8处理的略低于CK。石墨烯处理可显著增加土壤酸性蛋白酶活性，降低过氧化氢酶活性，并对蔗糖酶、脲酶、酸性磷酸酶和硝酸还原酶活性产生一定影响。在朝天椒生长中期，3个石墨烯处理的根区土壤铅和铬含量均低于CK，镉和砷含量高于CK，不同处理间的汞含量差异不大。在朝天椒果实中，3个石墨烯处理的镉和铬含量均比CK低，其中A8、B8和C8处理的镉含量分别较CK低18.52%、22.22%和19.75%，铬含量分别较CK低14.02%、39.25%和42.99%。对不同浓度石墨烯处理下的朝天椒根区土壤微生物测序结果显示，CK、A8、B8和C8处理的土壤微生物OTU总数分别为2016、2074、2182和2063，其中共有的OTU数为1106，特有的OTU数分别为218、224、445和221。对各处理的土壤微生物组成分析结果显示，土壤中的优势菌群为变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）、拟杆菌门（Bacteroidota）、酸杆菌门（Acidobacteriota）、绿弯菌门（Chloroflexi）和放线菌门（Actinobacteriota），均为农田土壤常见类群。【结论】在朝天椒定植后淋施0.35%石墨烯水溶液可在一定程度上提高朝天椒根区土壤肥力和酶活性，改善土壤理化性质和微生物群落结构，提高朝天椒的产量和品质。石墨烯具有作为碳肥在辣椒高产高效优质栽培上应用的潜力。

Effects of carbonized graphene on yield,soil nutrient of rhizosphere and microbial community structure of Capsicum annuum L.

【Objective】To explore the effects of carbonized graphene on yield，quality and rhizosphere soil nutrient，enzyme activity，heavy metal content and microbial community structure of Capsicum annuum，so as to provide a scientific basis for the application of graphene carbon-fertilizer in the cultivation of pepper with high yield，high efficiency and good quality.【Method】The fresh type of pepper was taken as the research object，based on of basic fertilization（CK）， 0.07% graphene aqueous solution（A8 treatment），0.35% graphene aqueous solution（B8 treatment）and 1.75% graphene aqueous solution（C8 treatment）were sprayed on the rhizosphere of C. annuum after planting. C. annuum fruit yield，nutritional indicators，heavy metal content in different organs of treated with different concentrations of graphene，as well as soil nutrients，enzyme activity and heavy metal content in the rhizosphere of C. annuum were measured. Soil microbial community structure of C. annuum treated with different concentrations of graphene was analyzed.【Result】Different concentrations of graphene treatment had certain effects on the yield and quality of C. annuum. The yield，vitamin C content and capsaicin content of B8 treatment were significantly increased by 6.40%，25.27% and 20.45% respectively compared with CK（P<0.05，the same below）. There was no significant change in protein content（P>0.05，the same below），soluble sugar content decreased significantly，while nitrate content increased significantly. There was no significant difference in the contents of total phosphorus，total nitrogen，total potassium and soil hydrolytic nitrogen in the rhizosphere of C. annuum among the treatments，but the contents of available phosphorus and available potassium of CK were higher or significantly higher than those of graphene treatments. The organic matter content of B8 treatment was slightly higher than that of CK，and that of A8 treatment was slightly lower than that of CK. Graphene treatment could significantly increase the activity of soil acid protease，reduce the activity of catalase，and have a certain impact on the activities of sucrase， urease，acid phosphatase and nitrate reductase. In the middle growth stage of C. annuum，the contents of lead and chromium in the rhizosphere soil of the three graphene treatments were lower than that of CK，and the contents of cadmium and arsenic were higher than that of CK. There was little difference in mercury content between different treatments. In the fruit of C. annuum，the contents of cadmium and chromium in the three graphene treatments were lower than that of CK， among which the contents of cadmium in A8，B8 and C8 treatments were 18.52%，22.22% and 19.75% lower than that of CK，and the contents of chromium were 14.02%，39.25% and 42.99% lower than that of CK，respectively. The sequencing results of soil microorganisms in the rhizosphere of C. annuum treated with different concentrations of graphene showed that the total number of soil microbial OTU treated with CK，A8，B8 and C8 were 2016，2074，2182 and 2063 respectively. The same OTU number in four samples was 1106，and the number of unique OTU was 218，224，445 and 221 respectively. The analysis results of soil microbial composition of each treatment showed that the dominant bacterial groups in the soil were Proteobacteria，Firmicutes，Bacteroidota，Acidobacterita，Chloroflexi and Actinobacterita，which were common groups in farmland soil.【Conclusion】Spraying 0.35% graphene aqueous solution after planting can improve soil fertility and enzyme activity in the rhizosphere of pepper to a certain extent，improve soil physical and chemical properties and microbial community structure，and improve the yield and quality of C. annuum. Graphene has the potential to be used as carbon fertilizer in pepper cultivation with high yield，high efficiency and high quality.