【目的】研究不同供磷浓度下盆栽杉木Cunninghamia lanceolate苗根系形态和生理响应机制及土壤养分和微生物变化规律。【方法】设置缺磷（P0）、正常供磷（P1）及高浓度供磷（P2）3个处理，测定不同供磷处理盆栽杉木苗根系形态和生理指标及土壤养分和微生物数量的时间动态。【结果】处理第30天时，P0植株地上部和整株干物质累积量最小，而根系干物质累积量和根冠比最大，分别是P1的2.07和5.37倍，差异显著；处理第15天时，P0根系磷吸收率最低而利用率最高，第30天时，其根系磷吸收率为P1的43.18％，而磷利用率为P1的231.59％；根系表面积和根尖数随处理时间增加呈增长趋势，第30天时，P0根系表面积为3.46 cm2，根尖数为56个，显著高于P1、P2处理；磷处理期间，酸性磷酸酶、超氧化物歧化酶活性和丙二醛含量均以P0最高，并与P1、P2差异显著；较之P1、P2处理， P0的土壤碱解氮明显升高，有效磷严重匮乏， pH、速效钾和阳离子交换量变化不大，酸性磷酸酶活性显著增强，真菌数量则有所降低。【结论】较之正常和高浓度供磷处理，缺磷胁迫导致杉木苗根系干物质累积量增加，根冠比增大，根系表面积和根尖数随胁迫时间延长而增大和增多；缺磷处理根系磷吸收率下降而利用率提高，根系的酸性磷酸酶、超氧化物歧化酶活性和丙二醛含量显著增大，同时盆栽土壤酸性磷酸酶活性显著增强，碱解氮含量明显增加，有效磷含量匮乏且真菌数量最少，表明缺磷处理对杉木苗根系生长及土壤养分和微生物数量影响显著。%[Objective] To demonstrate the morphological and physiological response of Cunninghamia lanceolate roots, and the variation of nutrient and microorganism contents in potting soil under phosphorus ( P) deficiency.[Method]Three treatments including P deficiency ( P0 ) , normal concentration P ( P1 ) and high concentration P (P2) were applied to potted C.lanceolate seedlings.The temporal dynamics of root phenotype and physiology, as well as the nutrient and number of microbes of the potting soil were measured.[Result] After 30 days treatment, P0 had the least accumulations of shoot and whole plant dry mass, and the highest accumulation of root dry mass and root/shoot ratio, which were 2.07 and 5.37 times of those of P1, respectively.Starting from day 15, the root P uptake rate of P0 had been the lowest while P utilization rate had been the highest.At day 30, the root P uptake and utilization rates for P0 were 43.18%and 231.59% of those for P1, respectively.Root surface area and root tip number in-creased with the increase of treatment time, and were 3.46 cm2 and 56 respectively for P0 at day 30, sig-nificantly higher compared to P1 and P2.During the entire treatment process, acid phosphatase, SOD activities and MDA content of P0 were significantly higher compared to P1 and P2 .Compared with P1 and P2 treatments, P0 had obviously higher content of soil alkali hydrolysable nitrogen, serious shortage in available P, minor differences in pH, available K and cation exchange capacity, significant increase in acid phosphatase activity, and decrease in the number of fungi.[Conclusion]P deficiency(P0) treatment led to increase in root dry mass accumulation and root/shoot ratio, increase in root surface area and root tip number with the increase of stress time, decrease in P uptake rate but increase in P utilization rate, and significant increase in root acid phosphatase, SOD activities and MDA content.In addition, acid phosphatase activity of the potting soil significantly increased, alkali solution nitrogen content obviously increased, available P content was in serious shortage and fungi content was the least for P0 compared to other treatments.Therefore, P deficiency has significant effect on root growth, as well as nutrient and number of microbes of potting soil.
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