黑麦草对土壤中苯并[a]芘动态变化的影响

本文通过盆栽试验初步研究了黑麦草 (LoliummultiflorumLam)对污染土壤中多环芳烃苯并 a]芘动态变化的影响。盆栽试验设计 3种苯并 a]芘处理浓度 ,分别为 1、10、10 0mgkg-1。将苗龄为 1周的黑麦草移植于受苯并 a]芘污染的土壤中 ,同时设置有相同的苯并 a]芘处理浓度但不种植物的对照试验。试验在2 0m3 的控温、控光的生长室内进行 ,土壤湿度维持在田间持水量的 6 0 %。通过 12 0d的温室盆栽试验 ,观察到土壤中苯并 a]芘的可提取浓度随着时间逐渐减少 ,种植黑麦草加快了土壤中可提取态苯并 a]芘浓度的下降。在 1、10、10 0mgkg-1苯并 a]芘处理浓度下 ,黑麦草生长的土壤中苯并 a]芘的减少率分别达 82 3%、74 0 %和 5 5 9%。结果还显示 ,随盆栽时间的延长 ,黑麦草根圈土壤中多酚氧化酶含量提高 ,这可能根圈土壤中可提取态苯并 a]芘含量降低有关。黑麦草的地上部可以积累苯并 a]芘 ,变幅在 0 0 6～ 3 6 0mgkg-1。初步认为 ,土壤具有缓解苯并 a]芘污染的自然本能 ,促进黑麦草生长 ,增强土壤多酚氧化酶活性 ,可提高黑麦草对苯并 a]芘污染土壤的修复能力。

DYNAMICS IN BENZO [a] PYRENE CONCENTRATIONS IN SOIL AS INFLUENCED BY RYEGRASS PLANTS

Dynamics in Benzoapyrene (BaP) concentrations in soil as influenced by ryegrass plants (Lolium multiflorum Lam) were studied in a greenhouse experiment. During the 120 days of plant growth, the extractable BaP concentrations in the soils decreased with time and were much less in soil grown with ryegrass plants. In the planted soil with application rate of BaP 1, 10, 100 mg kg -1 soil, BaP biodegradability amounted to 82. 3%, 74. 0% and 55. 9%, respectively. The planted soil had higher activity of polyphenoloxidase as compared with the unplanted soil. BaP concentrations in the plants ranged from 0. 06 to 3. 60 mg kg -1 and declined with the increasing number of days of plant growth. Ryegrass enhanced rhizo-degradation of BaP in the contaminated soil. Increase in ryegrass growth and polyphenoloxidase activity in the rhizosphere soil can improve the bioremediation capability of of BaP-contaminated soil by ryegrass plants.