不同供磷水平对盐碱地柳枝稷根系形态及土壤理化性质的影响

Effect of phosphorus supply levels on root morphology and soil physicochemical properties of switchgrass in salinealkali soil

为探究盐碱条件下柳枝稷(Panicum vigatum L.)对供磷水平的响应,以不同品种柳枝稷(Alamo加倍体、Alamo、Pathfinder)为材料进行根箱试验,分析比较了不同磷浓度(0、10、100 mg/kg)处理对柳枝稷根系形态、生理特征及土壤理化性质的影响。结果表明:随着施磷水平的增加,各品种柳枝稷生物量、根系形态、根系活力及土壤有效磷含量整体呈上升趋势,而根冠比、土壤p H值和酸性磷酸酶活性呈下降趋势,均在高磷(100 mg/kg)处理下达到最大值和最小值。与高磷处理相比,低磷(10 mg/kg)处理下3个品种柳枝稷土壤pH值分别增加了0.31、0.28、0.23个单位,酸性磷酸酶活性平均提高了58.0%、42.0%、13.5%。低磷条件下,Alamo加倍体具有较大的根表面积,并保持较高的根系活力,表现出较强的适应性,有利于降低土壤pH,提高土壤酸性磷酸酶活性。总体而言,Alamo加倍体对盐碱低磷胁迫的适应能力优于Alamo、Pathfinder。同时增加供磷水平能够促进盐碱地柳枝稷根系生长、改善土壤环境,提高其生物质产量。

In order to explore the response of switchgrass(Panicum Vigatum L.) to phosphorus supply level under salinealkali conditions,different varieties of switchgrass(three species,Alamo diploid,Alamo,Pathfinder) were used as materials for root box test,the root morphology and physiological characteristics of switchgrass and soil physicochemical properties treated with different phosphorus concentrations(0,10,100 mg/kg) were analyzed and compared.The results showed that with the increase of phosphorus application level,the biomass,root morphology,root activity and soil available phosphorus content of all switchgrass varieties showed an overall upward trend,while the root-shoot ratio,soil p H value and acid phosphatase activity showed a downward trend,all of which reached the maximum and minimum values under the treatment of high phosphorus(100 mg/kg).Compared with high phosphorus treatment,under low phosphorus(10 mg/kg) treatment,the soil p H value of three switchgrass varieties increased by 0.31,0.28 and 0.23 units,and the acid phosphatase activity increased by 58.0%,42.0% and 13.5% on average,respectively.Under the condition of low phosphorus,Alamo diploid has a large root surface area,maintains high root activity,and shows strong adaptability,which is conducive to lowering soil p H and improving soil acid phosphatase activity.Generally speaking,the adaptability of Alamo diploid to low phosphorus stress in saline-alkali soil is better than Alamo and Pathfinder.At the same time,increasing the phosphorus supply level can promote the root growth of switchgrass in saline-alkali soil,improve the soil environment and increase its biomass output.