Contractile roots are mostly studied in connection with their ability to shrink and pull the above-ground plant parts deeper into the soil. Lux et al. compare the unusual structure of these roots in Tritonia gladiolaris with regular, non-contractile roots of Zea mays and find that the process of contraction requires specific anatomical adaptation of the root base, with less-lignified and less-suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics are accompanied by more intensive translocation of cadmium ions from the basal part of contractile roots to the leaves than from the apical–subapical root parts. In the non-contractile roots of maize the opposite effects are seen, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part.
Cadmium translocation by contractile roots
Contractile roots require specific anatomical adaptation of the root base, with less-lignified & less-suberized tissues than in the subapical root.