Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.)

► Atmospheric PHE decreased growth, biomass partitioning and C allocation in clover. ► C allocation was modified in favor of leaves but at the expense of roots and stems. ► In roots, a decreased carbon exudation or allocation to symbionts was proposed. ► In leaves, carbon was retained in a non-structural form as secondary metabolites. ► BVOC emission was suggested as another loss process than respiration and exudation.