黄土高原紫穗槐丛枝菌根真菌与土壤因子和球囊霉素空间分布的关系

在黄土高原的陕西省甘泉、绥德、米脂、榆林4县(市)选取4个样地,研究紫穗槐不同深度土层丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)侵染率、孢子密度、球囊霉素和土壤因子之间的关系。结果表明:(1)AMF侵染率平均值绥德样地最大(100%),米脂样地最小(75.02%);孢子密度平均值米脂样地最大(5.91个/g),榆林样地最小(1.57个/g);4个样地孢子密度最大值均在0～10cm土层,且随土层加深而降低;AMF侵染率与孢子密度在各样地间差异显著,同一样地侵染率与孢子密度变化规律不一致。(2)榆林样地的有机碳、铵态氮、速效磷、脲酶和碱性磷酸酶活性平均值显著高于其他3个样地;除绥德、米脂样地的蔗糖酶和甘泉样地的碱性磷酸酶外,其他样地的土壤酶活性和球囊霉素含量均随土层加深而降低,且各土层之间差异显著,最大值均在0～10cm土层。(3)AMF侵染率与pH、总球囊霉素含量、易提取球囊霉素含量呈极显著正相关,与有机碳、硝态氮、速效磷含量呈显著正相关;孢子密度与速效磷、蔗糖酶、脲酶活性呈显著正相关,与铵态氮含量呈显著负相关。(4)第1、2主成分的累积方差贡献率达到56.4%,第1主成分主要综合了球囊霉素、AMF侵染率和孢子密度,第2主成分综合了pH和部分土壤因子信息。因此,球囊霉素、AMF侵染率、孢子密度、pH、部分土壤因子对决定土壤生态起主要作用。

Spatial Distribution of Arbuscular Mycorrhizal Fungi,Soil Factors and Glomalin in the Rhizosphere of Amorpha fruticosa Grown on the Loess Plateau

We collected the roots and rhizosphere soil samples from four different sites(Ganquan,Suide,Mizhi and Yulin) on the Loess Plateau in Shaanxi.The spatial distribution of AMF colonization,spore density and glomalin in the rhizosphere of Amorpha fruticosa were investigated,and their relationships with soil factors were analyzed.The result showed that:(1)The average AMF colonization rate from Suide was the highest of all the samples,which was up to 100%,and the lowest colonization rate was 75.02% from Mizhi.The spore density from Mizhi was higher than that of other samples,and it was 5.91/g.The lowest spore density was from Yulin,and it was 1.57/g.The highest spore density existed in the 0～10 cm layer of all samples,and with the soil depth increasing,the spore density decreased.In different regions,the differences of the AMF colonization rate and spore density were notable.The rate of AMF colonization did not correlate significantly with the spore density.Soil organic carbon(SOC),ammonia-N,olsen-P,urease and alkaline phosphatase from Yulin were significantly higher than those of other samples.Except for the sucrase from Mizhi and Suide and alkaline phosphatase from Ganquan,in 0～10 cm layer,the activities of most soil enzymes and glomalin reached the maximum,and declined with the increasing soil depth,which had a significant differences among the different layers.(2)AMF colonization had a significant positive correlation with SOC,nitrate-N,olsen-P,and it had a very significant positive correlation with pH,totally extracted glomalin related soil proteins(TEG) and easily extracted glomalin related soil proteins(EEG).Spore density had a significant positive correlation with olsen-P,sucrase,urease,and had a negative correlation with ammonia-N.TEG had a very significant positive correlation with EEG.(3)Principal component analysis(PCA) showed that the cumulative variance proportion of PCA1 and PCA2 were up to 56.4%.PCA1 contained glomalin,the AMF colonization rate and spore density.PCA2 contained pH and some soil factors.Therefore,the soil environment was mainly decided by these factors.