西北荒漠带油蒿丛枝菌根真菌空间分布特征

2018年7月和2019年7月,沿荒漠植物油蒿(Artemisia ordosica)天然分布地带,在内蒙古、宁夏、甘肃选取4个典型样地,采集油蒿根围土样和根样,研究丛枝菌根(arbuscular mycorrhiaze,AM)真菌地理分布以及土壤因子的生态功能。共分离鉴定6属32种AM真菌。在低海拔地区(1000~1300 m)和高海拔地区(1600~1900 m),球囊霉属(Glomus)和无梗囊霉属(Acaulospora)为优势属;在中海拔地区(1300~1600 m),球囊霉属和斗管囊霉属(Funneliformis)为亚优势属;盾巨孢囊霉属(Scutellospora)在3个海拔地区均为偶见属,近明囊霉属(Claroideoglomus)在低海拔地区为偶见属,在高、中海拔地区为伴生属;缩管柄囊霉属(Septoglomus)在3个海拔地区均为伴生属。油蒿根围AM真菌定殖分布表现出空间分布特征:从东到西随海拔高度增加,菌丝、泡囊、总定殖率和定殖强度总体呈渐增趋势,最大定殖率为70%,最小定殖率为13.3%。主成分分析表明,氨氮、湿度、脲酶和速效磷是影响AM真菌分布的主要因子。相关性分析表明,海拔与酸性磷酸酶、碱性磷酸酶、脲酶、速效磷极显著正相关(P<0.01),与有机碳显著正相关(P<0.05),与总提取球囊霉素极显著负相关。

Spatial Distribution Characteristics of Arbuscular Mycorrhizal Fungi of Artemisia ordosica in Desert Areas of Northwest China

Soil and roots samples under Artemisia ordosica were collected at four different sites(Dengkou,Alxa,Shapotou,Minqin)in northwest China in July 2018 and July 2019,respectively.A total of 32 species of AM fungal belonging to six genera were isolated and identified.Glomus and Acaulospora were dominant genus in low altitude(1000-1300 m)and high altitude(1600-1900 m).Glomus and Funneliformis were sub-dominant genus in the middle altitude area(1300-1600 m).The occasional genus at the three altitude was Scutellospora.Claroideoglomus was an occasional genus at low altitude and associated genera at high and middle altitude.The concomitant genus at these three altitudes was identified as Septoglomus.The colonization distribution of AM fungi showed the characteristics of spatial distribution:with the increase of altitude from east to west,the abundance of AM fungi showed a downward trend,and the Shannon Wiener index showed an upward trend.With the increase of altitude from east to west,the mycelium colonization rate,vesicle colonization rate,total colonization rate and colonization intensity increased,with 70%of maximum colonization percentage and 13.3%of the minimum.Principal component analysis showed that ammonia nitrogen,humidity,urease and available phosphorus were the main factors affecting the distribution of AM fungi.Correlation analysis showed that altitude was positively correlated with acid phosphatase,alkaline phosphatase,urease and available phosphorus(P<0.01),positively correlated with organic carbon(P<0.05),and negatively correlated with total extraction of glomycin.