石灰性土壤—小麦系统中钼元素的动态转运机制OA

This paper is the result of soil geochemistry. [Objective]Molybdenum(Mo),an essential micronutrient for plants,animals,and humans,plays critical roles in nitrogen metabolism and enzyme activity regulation.Globally,approximately 25%～40%of agricultural soils are Mo-deficient,and the allocation mechanisms of Mo in wheat cultivated in northern China's calcareous soil regions remain unclear.This study aims to elucidate the absorption,translocation,and enrichment patterns of Mo in the soil-wheat system through pot experiments,providing a scientific basis for optimizing Mo fertilization,improving wheat quality,and assessing human health risks.[Methods]Using the wheat cultivar"Shixin 828"as the test subject,six soil Mo concentration gradients(0,0.15,0.17,0.20,0.25,and 0.60 mg/kg)were established by exogenous sodium molybdate addition.A controlled outdoor pot experiment was conducted to measure Mo content in roots,stems,leaves,and grains in the jointing and maturity stages.Mo allocation mechanisms were analyzed using enrichment factors(EFs)and translocation coefficients(TCs).[Results]In the jointing stage,Mo accumulation followed leaves>roots>stems;in maturity,stems>grains>roots.Elevated soil Mo significantly increased Mo content in all tissues.The 0.60 mg/kg treatment yielded the highest stem Mo content(7.51 mg/kg)and grain enrichment(4.60 mg/kg).TCs decreased with rising soil Mo levels(from 2.02 to 1.78),suggesting that high Mo concentrations may inhibit root-to-shoot translocation efficiency.Soil available Mo exhibited a highly significant positive correlation(P<0.01)with tissue Mo content,with the strongest association observed in stems(r=0.878).[Conclusions]Mo allocation in wheat exhibits growth-stage specificity,with leaves as the primary enrichment site during jointing and stems/grains dominating in maturity.Soil available Mo content is a key regulator of wheat Mo uptake,with the 0.60 mg/kg treatment significantly enhancing grain Mo accumulation.High molybdenum(Mo)environments(>0.25 mg/kg)may limit grain Mo content thresholds by suppressing translocation efficiency.These findings provide theoretical support for precise Mo fertilizer application in calcareous soils and wheat nutritional fortification.