中国农业科学 ›› 2014, Vol. 47 ›› Issue (12): 2384-2394.doi: 10.3864/j.issn.0578-1752.2014.12.011

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

不同品种水稻对土壤中镉的富集特征及敏感性分布(SSD)

 孙聪, 陈世宝, 宋文恩, 李宁   

  1. 中国农业科学院农业资源与农业区划研究所/国家土壤肥力与肥料效益监测站网,北京100081
  • 收稿日期:2013-10-24 出版日期:2014-06-15 发布日期:2014-01-17
  • 通讯作者: 陈世宝,Tel:010-82106722;E-mail:chenshibao@caas.cn
  • 作者简介:孙聪,Tel:010-82106722;E-mail:suncong01@caas.cn
  • 基金资助:

    国家自然科学基金项目(41271490,21077131)、农业部农业公益性行业专项(200903015)

Accumulation Characteristics of Cadmium by Rice Cultivars in Soils and Its Species Sensitivity Distribution

 SUN  Cong, CHEN  Shi-Bao, SONG  Wen-恩, LI  Ning   

  1. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences/ National Soil Fertility and Fertilizer Effects Long-Term Monitoring Network, Beijing 100081
  • Received:2013-10-24 Online:2014-06-15 Published:2014-01-17

摘要: 【目的】研究不同水稻品种对土壤中镉(Cd)毒害的敏感性分布规律,测定基于保护95%水稻品种的土壤中Cd对不同水稻毒害的生态风险阈值HC5,为中国水稻Cd污染防治提供理论依据。【方法】利用中国南方具有代表性的两种水稻土,通过外源添加Cd制备成0、1.2、4.8、10、40、120 mg•kg-1的Cd污染土壤,以中国水稻主产区18个常规不同水稻品种为试材,通过温室盆栽试验测定不同Cd污染土壤对不同品种水稻的生物量、植株Cd含量及不同水稻Cd吸收的生物富集系数(BCF)影响。通过国际最新的累积概率分布函数逻辑斯蒂克分布模型(Log-logistic distribution)对不同水稻基于生物量的Cd毒性的剂量-效应关系进行拟合,利用物种敏感性分布模型 Burr-III 构建出Cd对不同水稻毒性的物种敏感度分布频次曲线(SSD),并基于此推导出不同水稻Cd毒性的物种敏感性分布频次和基于保护95%水稻品种的Cd毒性阈值HC5,并测定不同水稻Cd吸收BCF值与土壤中Cd有效态含量变化的定量关系。【结果】在酸性祁阳红壤中,不同品种水稻随着Cd处理浓度的增加,生物量明显下降,对Cd最为敏感的品种X-42,生物量降低86%,而对Cd耐性较强的品种Z-120生物量降低51%。当添加浓度为4.8 mg•kg-1时,JY-253、J-463、Z-611、J-899、T-15、X-6、T-167品种水稻的生物量达到最大,其余品种均在1.2 mg•kg-1处理下达到最高。与对照相比,不同品种水稻的生物量增加了4%—56%,说明低剂量Cd对水稻生长有一定的刺激效应。在中碱性广州水稻土中,不同品种水稻随着Cd处理浓度的增加,生物量没有显著性差异。在两种土壤中,生物富集系数(BCF)随着Cd处理浓度的增加而降低,在低镉(1.2 mg•kg-1)条件下,红壤水稻BCF的变化范围为0.0056(S-974)—0.0133(T-15),相差2.38倍;而广州水稻土的变化范围则为0.0018(L-42, LY-28)—0.0034(J-899),相差1.89倍。但是对于相同Cd浓度处理下,红壤中水稻的BCF大于广州水稻土,两者相差2—14倍,这可能与两种土壤的性质差异有关。祁阳红壤是酸性土壤,有机质匮乏,测得Cd有效态含量高,对水稻的毒害强,生物量降低的多;广州的水稻土则相反,高pH和有机质丰富的土壤对Cd吸附容量和固持力增加,对水稻毒害减弱,生物量变化不明显。土壤中Cd对以上18种水稻的毒性阈值浓度(EC50)变化范围为4.30—61.611 mg•kg-1,最高的为水稻X-45,最低的是水稻X-42,不同水稻品种之间EC50差别为1.0—4.32倍。【结论】不同水稻品种对土壤中Cd毒性胁迫有显著性差异,虽然Cd属于非必需元素,但不同水稻品种对低剂量Cd表现出不同的刺激效应;基于物种敏感性分布模型(Burr-III)测定结果表明,18种不同水稻具有明显的分布频次差异,其中,水稻X-42毒性阈值最小,对Cd胁迫最为敏感,水稻X-45则相反,表现出较强耐性。经过Burr-III模型的计算得到基于保护95%水稻品种的土壤中Cd50%抑制浓度值(HC550%)为4.93 mg•kg-1。

关键词: Burr-III模型 , 镉 , 水稻品种 , 敏感性分布 , 生态风险

Abstract: 【Objective】Understanding of the accumulation characteristics of Cadmium by different rice cultivars in soils and its species sensitivity distribution is necessary for determination of the hazardous concentration of Cd to rice cultivars of 5% of the tested species (HC5), the threshold values (HC5) of Cd to rice species will provide vital information for protection of Cd pollution to different rice cultivars and thereafter the food chains in China.【Method】Two typical paddy soils were collected from southern China, and the soils were polluted by Cd with different Cd addition levels of 0, 1.2, 4.8, 10, 40, and 120 mg•kg-1 in soils. Eighteen different rice cultivars from the main rice producing areas around China were selected for test plant species in this study. The biomass of the rice cultivars, the Cd concentrations in plants and thereafter the bioconcentration factor (BCFs) were investigated using pot experiments in green houses. The log-logistic distribution model was used to determinate the dose-response relationship of Cd toxicity to rice cultivars based on different endpoints. The response relationships of Cd toxicity to18 different rice species were fitted by cumulative probability distribution functions Log-logistic distribution model. The species sensitivity distributions (SSD) of Cd to rice was performed with the Burr-III type distribution model, and the different species sensitivity distribution of Cd toxicity frequency and 95% of rice varieties based on the protection of Cd toxicity thresholds HC5 were obtained and meanwhile, the quantitative relationship of BCFs with the bioavailability of Cd in soils was also determined in this study.【Result】 The biomass of different rice species decreased with the increasing concentrations of Cd in acidic soil from Qiyang, biomass of rice X-42 which was the most sensitive species to Cd stress decreased by 86%, but the biomass of rice Z-120 showed stronger tolerance to Cd stress decreased by 51%. When added at a concentration of 4.8 mg•kg-1, the biomasses of JY-253, J-463, Z-611, J-899, T-15, X-6, T-167 reached the maximum, and the others were at the concentration of 1.2 mg•kg-1. Compared with Cd0, the biomass of different varieties of rice increased by 4%-56%. This showed the stimulating effect of relatively lower level of Cd on rice growth. In alkaline soils from Guangzhou, there was no significant difference in the biomass of different rice species with increasing concentrations of Cd. The biologic concentration factor (BCFs) of Cd to rice species decreased with the increased spiked levels of Cd in both soils. In the low-Cd concentration (1.2 mg•kg-1), BCF in the red soil ranged between 0.0056 (S-974)-0.0133 (T-15), 2.38-fold difference; but in the paddy soil, the range of variation between 0.0018 (L-42, LY-28) -0.0034 (J-899), 1.89-fold difference. However, the BCFs of rice in Qiyang soil was higher than in Guangzhou soil under the same Cd level 2-14 times difference. This may be related to the nature of the soil. Qiyang red soil is an acidic soil, organic matter scarce, highly effective state of the measured Cd contention, and strong poisoned rice, reduced the multi-biomass. On the contrary, Guangzhou paddy soil which is high in pH and more organic matter, increased Cd absorption capacity and holding power, weakening poison rice biomass did not change significantly. Rice X-45 had the highest Cd toxicity threshold concentration (EC50, mg•kg-1), while rice X-42 had the lowest EC50. The EC50 of 18 rice species ranged from 4.30-61.611 mg•kg-1, with the variations differed from 1.0 to 14.32 folds.【Conclusion】Significant differences of response of rice cultivars to Cd stress were observed among the tested rice plant species, and hormesis effect of Cd stress to rice cultivars was also observed in this study although Cd was not included in the nutrients for rice plants. The results indicated that distinct difference existed among the tested rice species according to the accumulation of Burr-III type distribution model, e.g. the result showed that rice X-42 was the most sensitive species to Cd stress with the minimum toxicity threshold among the rice cultivars, on the contrary, rice X-45 showed a strong tolerance to Cd stress in soils. The maximum concentration of half (50%) inhibiting concentration of Cd to rice cultivars with protection of the 95% rice species (HC550%) was 4.93mg•kg-1 as determined by Burr-III model.

Key words: Burr-III model , cadmium , rice cultivars , species sensitivity distributions (SSD) , ecological risk