茶树对镍的吸收积累

Absorption and Accumulation of Nickel in Tea Plants

通过盆栽和水培试验,研究了镍元素在茶树中的分布规律及吸收累积特性.结果表明,土壤镍污染对茶树的生长和光合速率都有明显的抑制作用;镍处理浓度≥10 mg/L时,水培茶苗不仅出现严重的毒害症状,甚至部分茶苗整株死亡.盆栽和水培茶树各器官对镍的累积量与镍添加量呈极显著正相关关系.盆栽茶树各部位的镍含量由高到低的分布次序为:吸收根、主根、新梢、叶片、主茎,分配比约为:17∶10∶2.3∶1.7∶1;当添加10,20 mg/kg的外源镍,供试土壤的镍含量达到33.15,43.15 mg/kg时,新梢中的镍含量由对照的0.01 mg/kg升至8.72,18.75 mg/kg.水培茶树的分布次序由高到低为:主根、吸收根、主茎、枝条、叶片、新梢,分配比约为:2 0∶4 0∶1 1∶1.9∶1.7∶1.茶树吸收的镍大部分被吸收根所固定,但外源镍在茶树体内的活性以及向新梢迁移、富集的能力较强,镍污染容易影响茶叶卫生质量.应深入研究茶树各部位镍含量与各土壤因子相关性,以便制定更合理的土壤镍限量标准.

Nickel （Ni） absorption and accumulation in tea plants were studied by hydroponic and pot experiments. In the pot experiment, Ni contamination markedly inhibited the growth and photosynthesis of the plants. In the hydroponic experiment, Ni treatments with a concentration of ≥10 mg· L^-1 resulted in serious toxicity or even death to the tea plants. In both experiments, Ni accumulation in various organs of the plants was in a significant positive correlation with Ni rates. The distribution of Ni in potted tea plants appeared in the sequence： absorbing roots, main roots, tea flush, leaf blades, main stems, with a distribution ratio of 17 ： 10 ： 2.3 ： 1.7 ： 1. When 10 and 20 mg · L^-1 Ni was added into the soil, Ni content in the soil increased to 33.15 and 43. 15 mg · kg^-1 , and Ni content in tea flush rose from 0. 01 mg · kg^-1 in the control to 8.72 and 18.75 mg·kg^-1 respectively. Ni accumulation in hydroponically cultured tea plants was in the order： main roots, absorbing roots, main stems, branch, leaf blades, new flush, with a distribution ratio of 20 ： 40 ： 11 ： 1.9 ：1.7 ： 1. The Ni absorbed by tea plants was largely fixed in the absorbing roots. However, the high activity of Ni in tea plants and its strong ability of shift to and enrichment in the tea flush might affect the health quality of the tea products.