植物的不同组织对氰化物降解的可行性研究(英文)

Degradation of cyanide by woody plant tissues

氰化物是目前世界范围内最常使用的提取黄金等贵重金属的沥滤剂,其对自然生态环境的污染和破坏以及对人畜的毒性作用是众所周知的,氰化物污染的治理也就成为了环境工作者关注的焦点课题。植物细胞的悬浮液通常用于研究污染物的降解及在植物体内的生化反应机制。本实验直接用三种杨柳科植物的不同组织(根须、嫩茎、老茎和叶片)来观察和测定植物细胞线粒体中的氰丙氨酸合成酶(β-cyanoalanine synthase)转化氰化物的可行性。实验是在一封闭的玻璃器皿(100mL)中进行的(100mL的氰化钾溶液中加入1.0g(鲜重)的植物组织,氰化钾溶液的浓度0.444～0.457 CN mg·L^(-1))。在为期28 h的时间内,水溶液中的氰化物22.13～67.04％被植物的不同组织去除。最快的氰化物去除率发现在美洲黑杨(Populus deltoides)的叶片实验组(1.9449 mg CN/kg(鲜重)·h),苏柳(Salix matssudana Koidz×Salix alba L)的叶片实验组次之(1.7259 mg CN/kg(鲜重)·h),最慢的氰化物去除率发现在苏柳的嫩茎实验组(0.4934 mg CN/kg(鲜重)·h)。实验结果表明,选用植物的组织同样可以观察和测定污染物在植物体内的转化,特别是植物的叶片表现的尤其敏感。

Cyanide is the most widely used leaching reagent for gold extraction. Its environmental behaviour and fate is of significant environmental concern. β-cyanoalanine synthase(CAS) was found to be able to catalyse the conversion of cyanide to the ammino acid asparagine. This paper presents an investigation on the potential use of plant tissues to degrade cyanide. Excised plant tissues (1.0g fresh weight) from 3 woody plant speices out of the Salicaceae family were kept in a glass vessel with 100 mL spiked aqueous solution (oxygen-saturated deionized water) at room temperature of 20～23℃ for 28h. Samples were taken directly from the solution and determined photometrically at a wavelength of 638 nm. The cyanide removal rate was determined experimentally between 22.13% and 67.04% over a 28 h exposure period and varied with plant tissues and species. The maximum metabolic velocity, vmax, was 0.4934～1.9449 mg CN·kg^(-1) (fresh weight)·h^(-1). The highest removal velocity was 1.9449 mg CN·kg^(-1)(fresh weight)·h^(-1) with the leaves from Poplar trees (Populus deltoides), followed by 1.7259 mg CN·kg^(-1) (fresh weight)·h^(-1) with the leaves of hybrid willow trees (Salix matssudana Koidz×Salix alba L). The lowest removal velocity was 0.4934 mg CN·kg^(-1) (fresh weight)·h^(-1) with the new stem from hybrid willow trees. Results of this investigation indicated that the plant tissues were able to metabolize cyanide. The maximum removal capacity was found in plant leaves of the three groups tested. In conclusion, using excised plant tissues seems to be a feasible option for the characterization of the degradation pathways of cyanide.