干旱环境下羊柴DSE与AM真菌和土壤因子关系研究

Relationships of dark septate endophytes with arbuscular mycorrhiza fungi and soil factors under Hedysarum laeve in arid area

为了探明干旱环境下风蚀和水蚀对DSE（Dark septate endophytes）活动的影响,试验于2013年6月选取内蒙古正蓝旗青格勒图梁地,设置梁底、梁坡和梁顶不同样地,从羊柴（Hedysarum laeve）根围0~10、10~20、20~30、30~40、40~50cm土层采集土壤样品,研究了DSE分布规律以及与AM（arbuscular mycorrhiza）真菌和土壤因子的相关性。结果表明：羊柴根系能被DSE高度侵染,形成典型的有隔菌丝、微菌核和泡囊等共生结构。样地对DSE定殖率有显著影响,DSE菌丝、泡囊和总定殖率梁底〉梁顶〉梁坡,AM真菌定殖率梁底〉梁坡〉梁顶。相关性分析表明,DSE定殖率与AM真菌定殖率显著正相关,与土壤酸性和碱性磷酸酶极显著正相关。受风蚀和水蚀影响,3个样地土壤养分差异明显,梁底受侵蚀作用最弱,梁坡最强;DSE定殖和分布具有明显空间异质性,梁底显著高于其它样地,梁坡最低,DSE定殖状况能够良好的指示内蒙古梁地土壤环境的变化。这为进一步明确DSE生态功能,利用DSE资源促进干旱地区植被恢复和水土保持提供依据。

Hedysarum laeve is one of the arid‐active and sand‐fixation plants that can not only conserve soil ,but also block the wind ,reduce soil erosion ,so as to maintain the balance and stability of arid areas .To elucidate the effect of wind and water erosion and the distribution of dark septate endophytes （DSE） ,soil samples （0-50 cm deep） were collected under H .laeve at three different sites （foot‐slope ,mid‐slope ,top‐slope） in Inner Mongolia in June in 2013 . The results showed that the roots of H .laeve could be highly infected by DSE .DSE could form typical symbiotic structures ,such as septate hyphae ,microsclerotia ,vesicle and so on . Soil sampling sites and depth had a significant effect on colonization levels of DSE . DSE hyphae ,vesicle and total colonization showed the following trend across sites ：foot‐slope 〉top‐slope 〉 mid‐slope .The arbuscular mycorrhiza （AM ） fungi colonization was foot‐slope 〉mid‐slope 〉 top‐slope .DSE colonization had a positive correlation with AM fungal coloniza‐tion ,soil acid phosphatase and alkaline phosphatase .The soil nutrients were different caused by wind and water erosions in different sites .The effect of wind and water erosion of mid‐slope was the strongest .The results suggest that the colonization of DSE could be a better in‐dicator for the changes of soil resources .This research provides basis and references for fur‐ther clarifying the ecological functions of DSE and making full use of DSE to promote vegeta‐tion restoration and soil conservation in arid areas .