Chemical Forms and Distribution of Pb in the Leaves of Platycladus orientalis and Sophora japonica
A pot experiment combined with subcellular fractionation and chemical speciation sequential extraction techniques was carried out to study the lead( Pb) distribution and chemical forms in leaves of Platycladus orientalis and Sophorajaponica under different Pb concentration (CK 0 mg·kg-1, A 300 mg·kg-1, B 500 mg·kg-1, C 1000 mg·kg-1, D 2000 mg·kg-1). The result showed that the biomass of Platycladus orientalis and Sophorajaponica changed significantly under Pb stress. Most of Pb was distributed in the roots of two plants, and which increased with the Pb concentration in soil. A difference was observed in subcellular distribution of Pb and its chemical forms between the two plants leaves under Pb stress. Most of Pb was found to be bound to cell wall in the leaves of Platycladus orientalis and Sophorajaponica for all Pb treatments, and the proportion of Pb bound to cell wall was higher in Platycladus orientalis than Sophorajaponica. Less Pb was distributed in soluble fractions for both plants. The proportion of cell nucleus raised with Pb concentration increased, whereas the proportion of soluble fractions decreased. For the chemical forms, NaCl, acetic acid and HC1-extractable Pb were predominated in the leaves of the two plants, while the proportion of water and ethanol-extractable Pb were little. Pb supply increased the proportion of NaCl-extractable Pb firstly, and which reduced in leaves of Platycladus orientalis thereafter. On the contrast, the proportion of NaCl-extractable Pb in leaves of Sophora japonica increased gradually with Pb supply increased. Based on these fingings, Platycladus orientalis was likely to possess a higher tolerance to Pb than Sophorajaponica did.
国家科技期刊平台
NSTL
万方数据
维普
