平邑甜茶根系形态构型对氯化镉处理的响应

Responses of Root Morphology and Architecture in Malus hupehensis var. pingyiensis Seedlings to Cadmium Chloride

以平邑甜茶幼苗为试材,在水培条件下研究氯化镉对根系形态构型及根系丙二醛(MDA)含量的影响。结果表明:处理第5天时,只有10～20mg.L-1的氯化镉使根系分形维数、主根长度、根系直径显著变小;处理第15天时,2.5～20mg.L-1氯化镉均使根系分形维数、侧根长度、根系表面积、根系体积以及根系直径显著降低,降低程度随着氯化镉浓度的升高而增大;侧根生长比主根生长更易受到氯化镉抑制。2.5～20mg.L-1氯化镉可显著提高粗根所占比例并进而改变根系组成,随着氯化镉浓度的提高根系组成改变更明显。在2.5～20mg.L-1范围内,根系MDA含量随着氯化镉浓度的提高而显著增加;同样氯化镉浓度下,MDA变化幅度大于根系形态构型的变化幅度。氯化镉导致的细胞损伤是其改变根系组成和形态构型的重要原因。

Effects of cadmium chloride （CdCl2 ） on morphology and architecture of roots and the content of matondialdehyde （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^-1 CdCl2 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.