水稻镉高积累品种对镉的富集特性

【目的】研究了水稻Cd高积累品种对Cd的富集特性，并探讨其对Cd污染土壤的修复潜力，为Cd污染农田修复提供理论依据。【方法】以前期筛选出的Cd高积累品种泸17-T2171（Lu17-T2171）和武金4B（Wujin4B）为试验材料，普通品种泸恢17（Luhui17）为对照，采用土培试验，分析其在不同Cd处理条件下分蘖期和扬花期的Cd含量、积累量等变化特征，并探讨其对不同Cd污染程度土壤的净化能力差异。【结果】（1）随着Cd处理浓度的升高，Cd高积累品种的生物量逐渐增加，与对照相比（Cd0），Lu17-T2171生物量在分蘖期和扬花期Cd50条件下分别增加了33.96%和19.51%，Wujin4B分别增加了54.71%和15.22%。（2）高积累品种在分蘖期对Cd的吸收能力较强，特别是在Cd50条件下，Lu17-T2171地上部和根部Cd含量分别达到87.24和400.59 mg?kg-1，分别为Luhui17的2.38和2.86倍；Wujin4B地上部和根部Cd含量分别达到102.26和384.77 mg?kg-1，分别为Luhui17的2.79和2.86倍。两类水稻品种对Cd的富集系数均随着Cd处理浓度的增加而下降，且高积累品种富集系数明显大于普通品种。（3）高积累品种在扬花期对Cd的积累能力较强，在Cd50条件下，Lu17-T2171地上部和根部Cd积累量分别达到1 847.20和892.06 μg/pot，分别为Luhui17的2.91和2.74倍；Wujin4B地上部和根部Cd积累量分别达到1 895.37和783.42 μg/pot，分别为Luhui17的2.98和2.41倍，且高积累品种扬花期迁移率明显大于普通品种。（4）高积累品种的全株和地上部净化率明显高于普通品种。在Cd50条件下，Lu17-T2171扬花期整株和地上部净化率分别达到5.07%和3.42%，分别为Luhui17的2.86和2.90倍，Wujin4B整株和地上部净化率分别达到4.96%和3.51%，分别为Luhui17的2.79和2.98倍。【结论】在高Cd处理条件下，水稻Cd高积累品种对Cd有较强的吸收和富集能力，可作为农田Cd污染潜在的修复材料。

Accumulation Characteristics of Cadmium-Accumulated Rice Cultivars with High Cadmium Accumulation

【Objective】It is important to remediate Cd-polluted soils and select the cultivars with high Cd accumulation ability. The characteristics of cadmium-accumulated rice cultivars with high cadmium accumulation, and the purification ability to Cd-polluted soil were studied to provide a theoretical basis for restoration of Cd-polluted soil.【Method】Two Cd high-accumulation cultivars (Lu17-T2171 and Wujin4B) were screened earlier, with common variety Luhui17 as contrast. A pot culture experiment was carried out in a net room on the farm of Sichuan Agricultural University, Sichuan province, China in 2010, including soil culture experiment with Cd treatments of 0 mg•kg-1, 2 mg•kg-1, 10 mg•kg-1, and 50 mg•kg-1. The differences between cultivars in purification ability of rice to the soil Cd were discussed.【Result】As the concentration of Cd increased, the biomass of Cd high-accumulation cultivars was also increased. Biomass of Lu17-T2171 increased by 33.96% and 19.51%, respectively, at tillering stage and flowering stage with Cd50, compared with Cd0; while that Wujin4B increased by 54.71% and 15.22%, respectively. High-accumulation cultivars with stronger absorptive capacity to Cd at tillering stage. Under the condition of Cd50, Cd contents in shoot and root of Lu17-T2171 reached 87.24 mg•kg-1 and 400.59 mg•kg-1, respectively, which were 2.38 and 2.86 times higher than Luhui17, while those of Wujin4B reached 102.26 mg•kg-1 and 384.77 mg•kg-1, respectively, 2.79 and 2.86 times higher than Luhui17. Enrichment factor of both rice cultivars decreased as Cd concentration increase, moreover, the high-accumulation cultivars were apparently higher than common cultivars. High-accumulation cultivars with stronger ability to accumulate cadmium at flowering stage. Under the condition of Cd50, Cd accumulations in shoot and root of Lu17-T2171 reached 1 847.20 μg/pot and 892.06 μg/pot, respectively, 2.91 and 2.74 times higher than Luhui17, while those of Wujin4B reached 1 895.37 μg/pot and 783.42 μg/pot, respectively, 2.98 and 2.41 times higher than Luhui17. Moreover, the migration rate of high-accumulation cultivars at flowering stage was obviously higher than that of common cultivars. The purification rate in plant and shoot of high-accumulation cultivars was apparently higher than that in common cultivars. Under the condition of Cd50, the purification rate in plant and shoot of Lu17-T2171 reached 5.07% and 3.42% at flowering stage, 2.86 and 2.90 times higher than Luhui17, while those of Wujin4B reached 4.96% and 3.51%, 2.79 and 2.98 times higher than Luhui17. 【Conclusion】 Cd high-accumulation rice cultivars showed a high absorptive capacity and accumulation ability to Cd at tillering stage and flowering stage. Thus, it can be taken as potential restoration material for Cd-polluted farmlands.