马尾松幼苗根系分泌物对土壤酶活性和养分的影响

Effects of root exudates of Pinus massoniana seedlings on enzyme activity and nutrient in soil

【目的】掌握菌根化马尾松根系分泌物对土壤肥力的作用规律,为马尾松菌根苗栽培及土壤养分调控提供指导。【方法】将接菌Sl13和Sl12及不接菌(NS)马尾松的不同浓度根系分泌物施加到盆栽马尾松幼苗土壤中,浓度设置为高、中、低3水平(1、0.5、0.25 mg·mL^(-1)),1%乙醇作为空白对照CK,测定盆栽土壤酶活性和土壤养分含量。【结果】接菌的马尾松根系分泌物,提高了土壤脲酶和酸性磷酸酶的活性及有机质含量,但土壤pH值有所降低。与CK相比,高浓度处理下的接菌Sl12的土壤脲酶活性提高20.64%,接菌Sl13的酸性磷酸酶活性提高11.10%,接菌Sl13的土壤pH值下降6.76%;中浓度处理下的接菌Sl13和Sl12的脲酶活性均提高22.47%;低浓度处理下的接菌Sl13的脲酶活性和有机质分别提高26.71%、10.51%。但3种浓度处理下的接菌根系分泌物对多酚氧化酶活性、全氮、全磷、全钾、碱解氮、有效磷及速效钾影响均较小。不接菌马尾松根系分泌物可提高土壤pH值,但对土壤脲酶、酸性磷酸酶、多酚氧化酶活性及土壤有机质、氮、磷、钾含量均无显著影响。相关性分析表明施加马尾松根系分泌物后的土壤酶活性与土壤养分密切相关。【结论】接菌马尾松根系分泌物增强土壤酶活性,促进土壤有机质积累,改善土壤肥力。

【Objective】To explore the effect of mycorrhizal root exudates of Pinus massoniana on soil fertility and provide theoretical guidance for the cultivation of mycorrhizal seedlings of P.massoniana.and the regulation of soil nutrients.【Method】Different concentrations of root exudates from seedlings inoculated with Sl13 and Sl12 and non-mycorrhizal(NS)seedlings were applied to soil in seedlings pot.The concentrations were set at high,medium and low levels(1,0.5,0.25 mg·mL^(-1)),and 1%ethanol was used as the blank control CK.The enzyme activity and soil nutrient content in soil were measured.【Result】Inoculating root exudates could increase soil urease activity,acid phosphatase activity and organic matter content,and could reduce the pH value.At high concentration,the activities of urease in soil inoculated Sl12 and acid phosphatase in soil inoculated Sl13 increased by 20.64%and 11.10%,respectively,and the pH value decreased by 6.76%at inoculating Sl13.At high concentration,the urease in soil inoculated both Sl13 and Sl12 increased by 22.47%.At low concentration,the urease and organic matter in soil inoculated Sl13 increased by 26.71%and 10.51%,respectively.However,the effect of inoculating Sl13 and Sl12 didn’t have the effect on activity of polyphenol oxidase,and contents of total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,available phosphorus and available potassium at three concentrations treatments.Non inoculating root exudates could increase the soil pH value,but had no significant effect on soil urease,acid phosphatase,polyphenol oxidase and soil organic nitrogen,phosphorus and potassium.Correlation analysis showed that soil enzyme activities were closely related to soil nutrients after applying root exudates of Pinus massoniana.【Conclusion】Mycorrhizal root exudates of P.massoniana can improve soil enzyme activity,promote soil organic accumulation and improve soil fertility.