[Objective]The physiological role of the sodium humate in imparting resistance to heavy metal stress in wheat seedlings was explored by applying sodium humate in cadmium (Cd) stressed soil. [ Method ]Different methods of sodium humate application, viz., seeds soaking, irrigation and soil amendment were used to stndy their effects on growth and development of wheat seedlings under Cd stress conditions, and the absorption and accumulation of Cu, Zn, Fe, Mn and Cd were investigated. [Results]The application of sodium humate promoted the growth and development of wheat seedlings, relieved the toxicity of Cd and increased the dry matter accumulation in wheat seedlings. Amendment of sodium humate with soil gave the best results. Different modes of soidum humate application significantly reduced Cd accumulation in wheat seedlings and promoted the absorption and accumulation of Cu, Zn, Fe and Mn. The efficiency of different application modes reduced gradually with increase in severity of Cd stress. [ Conclusion ]The studies revealed that application of sodium humate increased the yield of wheat by providing tolerance to Cd toxicity, therefore, it may be used as eco-friendly soil amendment in Cd stressed soils for sustaining productivity.%[目的]研究镉(Cd)胁迫土壤中施用腐植酸钠对小麦幼苗的生物效应,探讨腐植酸钠在抗重金属胁迫方面的生理作用.[方法]以春小麦品种为试验材料,采用盆栽试验的方法研究腐植酸钠不同施肥方式(种子浸种、土壤灌施、土壤混施)对Cd胁迫小麦幼苗生长发育及矿质元素(Cu、Zn、Fe、Mn、Cd)吸收和累积的影响.[结果]采用不同施肥方式施用腐植酸钠可促进小麦幼苗的生长发育,缓解Cd对小麦幼苗的毒害,促进小麦幼苗干物质的积累,其中以土壤混施方式生物量增幅最大；在背景土壤中,不同腐殖酸钠处理能明显抑制小麦幼苗对Cd元素的吸收,促进小麦幼苗对Cu、Zn、Fe、Mn营养元素的吸收和积累；随着Cd胁迫程度增加,不同腐植酸钠处理抑制小麦幼苗Cd吸收能力逐渐减弱,不同施肥方式对小麦幼苗Cu、Zn、Fe、Mn营养元素的吸收累积影响存在差异.[结论]在重金属污染土壤中增施腐植酸肥料,可以明显减轻重金属元素对植物造成的伤害,这对于改善土壤环境和实现农业绿色生产具有重要应用价值.
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