Effects of Nanoparticle Hydroxyapatite on Growth and Antioxidant System in Pakchoi (Brassica chinensis L.) from Cadmium-Contaminated Soil

The effects of nanoscale particle hydroxyapatite (nHAP) on biomass, Cd uptake, the level of chlorophyll, vitamin C, malondialdehyde (MDA), and the activities of antioxidant enzymes, including SOD, CAT, and POD in pakchoi in Cd-contaminated soil, were evaluated by conducting pot experiment. Results showed that, by application of the 5 g·kg−1, 10 g·kg−1, 20 g·kg−1, and 30 g·kg−1nHAP in 10 mg·kg−1Cd-contaminated soil, the biomass of plant increased by 7.97%, 13.21%, 19.53%, and 20.23%, respectively. In addition, the reduction of Cd in shoots was 27.12%, 44.20%, 50.91%, and 62.36% compared to control samples. It was found that the supplement of the nHAP can increase the level of chlorophyll and vitamin C and decrease the level of MDA in plant shoots. Furthermore, the increment activities of SOD, CAT, and POD can be observed after addition of nHAP in Cd-contaminated soil. The results confirmed that nHAP can be applied to reduce the plant uptake of Cd and resist the Cd stress in the plant in Cd-contaminated soil.