Objective  Accumulation and food safety of cadmium in first crop and ratoon rice were studied.

  Method  In a greenhouse experiment, plants of Xiangliangyou 900 , touted as the “Super Rice”, were grown in pots with artificially added Cd in the soil at a rate of 0 (CK), 0.2, 0.4, 0.8, 1.2, or 1.5 mg·kg⁻¹. Cd contents in the roots, stems, leaves, and grains of the first and ratoon crops of the rice were determined, cumulation pattern analyzed, and risk of safety for consumption assessed.

  Result   Cd in various organs of the rice plants of both first and ratoon crops increased with increasing Cd in soil in the order of roots＞leaves＞stems＞grains. In the ratoon season, the plants contained less Cd than in the first season. The roots of the first crop plants contained Cd in the range of 0.2317–0.9581 mg·kg⁻¹, which was 5.1%–20.5% and averaging 15.2% higher than the ratoon counterparts of 0.2128–0.7802 mg·kg⁻¹. The stems of the first crop plants had Cd in the range of 0.0212–0.0846 mg·kg⁻¹, which was 10.8%–42.6% and averaging 29.7% higher than the ratoon counterparts of 0.0189–0.0621 mg·kg⁻¹. In the leaves, the first crop plants showed Cd in the range of 0.0273–0.1157 mg·kg⁻¹, which was 10.3%–65.6% averaging 45.5% higher than the ratoon plants of 0.0245–0.0689 mg·kg⁻¹. And in the grains, the Cd content of the first crop rice was in the range of 0.0172–0.0516 mg·kg⁻¹, which was 12.8%–53.1% averaging 33.2% higher than 0.0150–0.0312 mg·kg⁻¹ of the ratoon plants. Other than CK, at a same level of Cd in the pot soil, significant differences on Cd contents between the two different crops of same rice plants were observed (P＜0.05). The capacity of accumulating Cd ranked by different organs was roots＞leaves＞stems＞grains. The heavy metal risk coefficients for individual organs of the ratoon rice were all less than 1.

  Conclusion   Cd in various organs were less in the ratoon than the first crop rice. After harvest of first crop, the regenerated roots and stems on a ratoon rice plant did not inherit or transfer the Cd. Consequently, consumption of ratoon Xiangliangyou 900 rice would mean a reduced food safety risk for the consumers.