Detoxification mechanism of plant to Cd: Subcellular distribution and forms of Cd in Typha latifolia L.

摘要

The influences of Cd~(2+) on the subcellular distribution and chemical speciation of Cd in Typha latifolia L. in hydroponic system were investigated. The results showed that the accumulation of Cd increased with its supply and the highest Cd concentration occurred in roots, followed by rhizomes and leaves. Increased Cd concentration in the medium resulted in an enhancement in Cd uptake in various subcellular fractions of cattail, with the most of Cd was localized in cell walls, the second in soluble fraction, and the lowest in organelle containing fractions. The greatest amount of Cd was found in the extraction of 1 mol·L~(-1) NaCl, followed by 2% HAC, deionized water, 80% ethanol, residues and the least in 0.6 mol·L~(-1) HCl in all test tissues. It could be suggested that the protective mechanisms, especially retention of Cd in roots, cell walls binding with metal, metal ion compartmentation in vacuoles, and Cd forms existing in undissolved and integrated with pectates and protein, evolved by cattail play an important role in Cd detoxification.