Abstract:

Effects of cadmium chloride (CdCl₂) on morphology and architecture of roots and the content of malondialdehyde (MDA) in roots were studied using seedlings of Malus hupehensis var. pingyiensis grown in solution culture system. The results showed that 10-20 mg·L^-1CdCl₂ significantly decreased the fractal dimension (FD) of roots, taproot length, and root diameter in 5 days after treatment. The FD, the length of lateral roots, the surface area, volume and diameter of roots all decreased in 15 day treatment with 2.5-20 mg·L^-1 CdCl₂. The growth of lateral roots was more susceptible to CdCl₂ than taproots. CdCl₂ of 2.5-20 mg·L^-1 increased the proportion of thick root and altered the composition of roots significantly. The change of root composition was more significant with the increasing of CdCl₂ concentration. MDA content in roots increased significantly with 2.5-20 mg·L^-1 CdCl₂ treatment At the same concentration of CdCl₂, the change degree of root architecture parameters was higher than that MDA content in roots. The alteration of root architecture and morphology was derived from cell damage caused by CdCl₂.

Key words: cadmium, Malus hupehensis var. pingyiensis, fractal dimension, root architecture