土壤种子库与矿业废弃地植被恢复研究:定居植物对重金属的吸收和再分配  

UPTAKE AND TRANSLOCATION OF HEAVY METALS IN DOMINANT PLANTS OF SOIL SEED BANKS INTRODUCED TO A LEAD/ZINC MINE TAILINGS POND

作　　者：张志权[1] 束文圣[1] 蓝崇钰[1] 黄铭洪[2] 

机构地区：[1]中山大学生命科学学院生物系,广州510275 [2]香港浸会大学生物系

出　　处：《植物生态学报》2001年第3期306-311,共6页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金!项目 ( 3 9870 14 5 );广东省自然科学基金!项目 ( 960 0 62 )

摘　　要：研究了从引入的土壤种子库中所萌发 ,并成功在铅锌尾矿上定居的 4个优势种植物 ,雀稗 (Paspalumthunbergii)、双穗雀稗 (P.distichum)、黄花稔 (Sida rhombifolia)和银合欢 (L eucaena leucocephala) ,对重金属的吸收及其在体内的再分配。植物组织中铜 (Cu)和锌 (Zn)的浓度 ,除了雀稗和双穗雀稗根中的锌浓度分别为 34 4.2 m g· kg- 1和 331.9m g· kg- 1显得较高外 ,其余仍属植物体内正常水平范围 (Zn:2 7～ 15 0 m g· kg- 1 ,Cu:5～ 30 m g· kg- 1 )。草本植物雀稗、双穗雀稗和黄花稔对有毒重金属元素铅 (Pb)的吸收表现出不同的模式 ,Pb在地上部与地下部分的浓度比以雀稗最低 (为 0 .2 0 9) ,表明雀稗所吸收的 Pb大部分被滞留在根部 ,使之较少影响到地上部茎叶的光合作用功能及生长 ,从而使植物对重金属 Pb环境更具耐性。相反 ,双穗雀稗和黄花稔则较高 (分别为 0 .5 0 9和0 .6 5 3) ,显示所吸收的 Pb较多地被转移到便于收获移走的地上部分 ,因而具有较大的植物修复潜力(Phytorem ediation potential)。木本植物银合欢 ,所吸收的重金属 Pb总量的 80 %以上是积累在根、茎的皮和木质部及枝条部分 ,只有 15 %左右分布在叶片中。这表明随着生长 ,有越来越多的 Pb被吸收和累积在更新周期较长的器官中 ,只?The uptake and translocation of lead (Pb), zinc (Zn) and copper (Cu) was studied in seed bank emergent species established on introduced topsoil covering a Pb/Zn mine tailings pond. The four dominant species from this vegetation were targeted in this study: the grasses Paspalum thunbergii and P. distichum , the herb Sida rhombifolia and the woody Leucaena leucocephala . Concentrations of Zn and Cu in the tissues of these species fell into the ‘sufficient' or ‘normal' range. Zn and Cu of these plants ranged 27～150 mg·kg -1 and 5～30 mg·kg -1 respectively. The roots of P. thunbergii and P. distichum , were exceptions with high Zn concentrations (344.2 and 331.9 mg·kg -1 , respectively). The three non woody species had different metal uptake pattern as well as different adaptation to the toxic metal tailings. The shoot/root ratios for the toxic element Pb in P. thunbergii, P. distichum and S. rhombifolia were 0.209, 0.509 and 0.653 respectively. P. thunbergii , with low shoot/root Pb ratio might better adapt to grow on Pb contaminated land as its transport of Pb from roots to tops was comparatively restricted. The high shoot/root lead ratios of P. distichum and S. rhombifolia indicated that a greater portion of the total metal accumulation in harvestable tissues, and these plants therefore had a higher phytoremediation potential. The Pb uptake pattern of the woody legume L. leucocephala revealed that a high Pb concentrations accumulated in the root, branch, stem bark and xylem, accounted for more than 80% of total metal in this plant. This indicated that this woody plant had superior metal phytoremediation potential as a large quantity of Pb was accumulated in the plant for a relatively long period of time, while only a small portion of Pb, in the leaves (about 15%), would be returned to the environment as litter.

关 键 词：重金属吸收 雀稗 双穗雀稗 黄花稔 银合欢 土壤种子库 矿业废弃地 植被恢复 

分 类 号：Q948[生物学—植物学]