栗钙土施镍对小白菜的生物效应及其临界值

为确定Ni的毒害临界值,指导镍肥合理使用,研究了栗钙土施Ni对小白菜(Brassica chinensisL.)的生物效应。结果表明,施Ni量低于25 mg/kg促进小白菜干物质积累,随施Ni量增加,小白菜生长明显受到抑制;土壤施Ni明显增加小白菜茎叶和根系中Ni、Cu、Fe、Mn、Mg元素的含量,而降低Ca元素的含量,Zn元素的含量在茎叶和根系中分别表现为下降和增加;4种提取剂提取土壤中有效态Ni含量,均能较好反映植物吸收与生态危害状况,尤以DTPA提取的效果最佳。以生物减产量突变点为依据,暂定栗钙土壤中Ni的毒性临界值为:土壤有效态Ni含量为6.83 mg/kg(DTPA)、土壤全Ni含量为62.03 mg/kg、茎叶Ni含量为16.36 mg/kg。

The biological effect on Chinese cabbage and critical concentration of Ni application in chestnut soil

In order to determine the critical value of Ni toxicity and to direct Ni application the biological effects on Chinese cabbage of Ni application in chestnut soil were investigated.The results showed that when Ni was applied at lower than 25 mg/kg,dry weight of Chinese cabbage was accelerated.Above this concentration,the growth was inhibited.The contents of Ni,Cu,Fe,Mn and Mg in stems,leaves and roots were obviously increased,while Ca content was decreased when Ni was applied in the soil.As for Zn,its content was decreased in stems and leaves and increased in roots.When four kinds of extracting agents were used,the content of available Ni in soil perfectly indicated the conditions of plant absorption and ecological risk,especially when DTPA was used.Based on the biomass signifiant reduction,the critical concentration of Ni in chestnut soil was temporarily confirmed as follows: the contents of available and total Ni in the soil were 6.83 mg/kg(DTPA) and 62.03 mg/kg respectively,and available Ni in stems and leaves was 16.36 mg/kg.