枸杞深色有隔内生真菌定殖规律及其与土壤因子的相关性

利用采自宁夏银川市金凤区和西夏区两个枸杞栽培区0~20、20~40和40~60 cm共3个土层深度的枸杞根系和根围土样，研究枸杞 (Lycium barbarum)根系深色有隔内生真菌 (dark septate endophytes，DSE)的定殖规律及其与土壤因子的相关性，以期为充分利用DSE资源和基于生物技术促进荒漠植被恢复和生态改良提供依据。结果表明，DSE可定殖于枸杞根系形成深色、有隔菌丝，微菌核多呈聚合型和离散型。两样地DSE定殖率差异显著，金凤区样地DSE平均总定殖率（73.27%）显著高于西夏区样地 （23.54%）；不同土层DSE定殖率有差异，两样地DSE总定殖率、菌丝定殖率和微菌核定殖率最大值均出现在20~40 cm土层。两样地不同土层深度间土壤因子的分布差异显著，主成分分析显示pH、碱解氮、速效磷、有机质、碱性磷酸酶和蔗糖酶能综合反映银川市两枸杞样地根际土壤养分状况。方差分解分析结果表明，DSE定殖受到样地和土壤因子的共同影响。相关性分析表明，DSE定殖在两样地间存在较大差异，金凤区样地DSE总定殖率与有机质显著正相关，与速效钾极显著负相关；DSE菌丝定殖率与有机质、速效磷和碱解氮显著正相关，与速效钾和pH显著负相关。西夏区样地DSE总定殖率和微菌核定殖率与pH极显著正相关；DSE菌丝定殖率与有机质、速效磷和脲酶显著负相关。上述结果说明，枸杞根系能被DSE侵染，DSE定殖具有明显的垂直空间异质性，并与土壤因子密切相关。

Colonization of Dark Septate Endophytes Fungi in Lycium barbarum and Its Correlation with Soil Factors

In the present study, we investigated the colonization of dark septate endophytes (DSE) in the roots of Lycium barbarum and its correlation with soil factors, and collected the root and inter-root soil samples at three soil depths of 0-20 cm, 20-40 cm and 40-60 cm from cultivation area of L.barbarum in Jinfeng district and Xixia district of Yinchuan in Ningxia, so as to provide a basis for the full utilization of DSE resources and biotechnology-based promotion of desert vegetation restoration and ecological improvement.The results showed that DSE could colonize the root system of L.barbarum, form dark and septate hyphae, and generate polymeric and discrete microsclerotia.The rate of DSE colonization was significantly different between the two sample plots.The mean total colonization rate of DSE in Jinfeng (73.27%) was significantly higher than that in Xixia (23.54%).The DSE colonization rates varied among different soil layers.The maximum values of total DSE colonization rate, hyphae colonization rate and microsclerotia colonization rate were all found at the 20-40 cm soil layers of both sample plots.The distribution of soil factors differed significantly among different soil depths in the two samples.The principal component analysis showed that the rhizosphere soil nutrient status was affected comprehensively by pH, alkali hydrolyzable nitrogen, available phosphorus, organic matter, alkalin phosphatase and sucrase in two sample plots of Yinchuan.Variation partitioning revealed that the colonization of DSE fungi was affected by a combination of sample site and soil factors.The correlation analysis showed that DSE colonization differed significantly between the two samples.In the sample plot of Jinfeng district, the total DSE colonization rate had significantly positive correlation with organic matter, and significantly negative correlation with available potassium.The DSE hyphae colonization rate had significantly positive correlation with organic matter, available phosphorus and alkaline nitrogen, and significantly negative correlation with available potassium and pH.In the sampling site of Xixia, the total DSE colonization rate and the microsclerotia colonization rate had significantly positive correlation with pH, while the DSE hyphae colonization rate had significantly negative correlation with organic matter, available phosphorus and urease.The findings in this study indicated that the root system of L.barbarum can be infested by DSE, the colonization exhibits obvious vertical spatial heterogeneity and is closely related to soil factors.