放线菌对旱区露天煤矿排土场红豆草根系生长及根际土壤肥力的影响

针对旱区露天煤矿排土场土壤退化问题，采用高效放线菌菌剂接种及原位盆栽试验，探究了放线菌对新疆黑山露天煤矿排土场红豆草根系生长及根际土壤肥力的影响。结果表明:(1) 干旱条件下，放线菌接种可显著促进红豆草根系形态发育及生长。与对照相比，接种放线菌红豆草总根长、平均根系直径、根表面积及根总体积较不接菌对照均显著增加(P<0.05)；根鲜重、茎叶鲜重及总鲜重较对照分别增加了77.24%、130%及103.49%。(2) 接种放线菌显著增强了红豆草的抗旱性。接菌根谷胱甘肽、脯氨酸含量和根系活力分别增加了35.36%、229.23%和363.75%，降低了丙二醛含量和根细胞质膜透性。(3) 接种放线菌显著提高了红豆草根际土壤肥力。供试放线菌在红豆草根际土壤中定殖量为2.5×105 cfu/g，接种后红豆草根际土壤细菌和放线菌总数较对照分别增加了113.7%和563.64%；根际土壤多酚氧化酶、脲酶及碱性磷酸酶活性较对照均达显著性增加(P<0.05)；进而显著提高了根际土壤全氮、有效磷和速效钾含量，其中土壤全氮增加量最大。(4) 相关分析表明，红豆草根生物量与根际细菌和放线菌数量、土壤脲酶活性、碱性磷酸酶活性及全氮含量呈显著正相关(P<0.01)。结果证实了土壤接种放线菌通过增强植物的抗旱性，提高根际土壤微生物数量、酶活性及肥力水平，显著促进植物根系发育及生长，为旱区煤矿植被恢复及退化土壤改良提供了科学依据。 

Effects of actinomycetes on root growth of onobrychis viciaefolia and rhizosphere soil fertility in dumping site of open-pit mine in arid area

In order to resolve the issue of soil degradation in the dumping site of open-pit coal mine in arid area, the effects of actinomycetes on the root growth and rhizosphere soil fertility of onobrychis viciaefolia in the dumping site of Xinjiang Heishan Open-pit Coal Mine were investigated by highly efficient actinomycete inoculation and in-situ pot experiment. The results show that: (1) Under the drought conditions, actinomycetes inoculation could significantly promote the development of root morphology and the growth of onobrychis viciaefolia. Compared with the control without actinomycetes inoculation, the total root length, average root diameter, root surface area and total root volume of onobrychis viciaefolia were significantly increased (P<0.05), and the fresh weight of root and stem leaf and the total fresh weight were increased by 77.24%, 130% and 103.49% respectively. (2) Actinomycetes inoculation significantly enhanced the drought resistance of onobrychis viciaefolia. Meanwhile, the root glutathione, proline content and root activity were increased by 35.36%, 229.23% and 363.75% respectively, while malondialdehyde content and the permeability of the root cytoplasmic membrane were reduced. (3) Actinomycetes inoculation significantly improved the rhizosphere soil fertility of onobrychis viciaefolia. Specifically, the colonization amount of actinomycetes for test in rhizosphere soil of onobrychis viciaefolia is 2.5 × 105 cfu/g. The total number of soil bacteria and actinomycetes in the rhizosphere were increased by 113.7% and 563.64% respectively. Besides, the activities of soil polyphenol oxidase, urease and alkaline phosphatase were significantly increased (P<0.05) by comparison with the control. Thus, the contents of total nitrogen, available phosphorus and available potassium in rhizosphere soil were significantly increased by actinomycetes, of which the total nitrogen reached the largest increase rate. (4) Correlation analysis shows that root biomass of onobrychis viciaefolia was significantly and positively correlated with the quantity of soil bacteria and actinobacteria, the activity of urease and alkaline phosphatase, and the total nitrogen (P<0.01). These results also verify that actinomycetes inoculation in soil could enhance the drought resistance of plant, increase the number of microorganisms, enzyme activity and fertility in rhizosphere soil, and significantly promote the development and growth of plant root, thus providing scientific basis for vegetation restoration and degraded soil improvement in arid coal mining areas.