几种植物对城市尾水中重金属的去除效果研究

为了筛选适合吸收城市尾水中重金属的植物品种,研究了酸模(Rumex acetosa L.)、莎草(Cyperus glomeratus L.)和空心菜(Ipomiea aquatica Forsk)3种植物对城市尾水中重金属Zn、Cu、Pb和Cd的去除效果,并以酸模为材料,研究其对人工模拟重金属Cd和Pb污染水体的适应性。结果表明:酸模、莎草、空心菜3种植物对城市尾水中Zn、Cu、Cd、Pb的去除率分别为74.33%、60.43%、45.45%、36.43%,其中酸模对重金属的去除效果最好,其次是莎草和空心菜。酸模对尾水中Zn、Cu、Cd、Pb的去除率分别达到了86.63%、90.37%、76.81%、66.67%。Cd和Pb含量分别在0.5～2.0mg/L和0.2～0.4mg/L时酸模有较好的耐性。因此,酸模更适合于城市尾水中重金属的吸收修复,且对一定质量浓度Cd和Pb表现出较好的去除效果。     

狼尾草等6种植物对十溴联苯醚污染土壤的生理响应及其修复效果

考察了狼尾草、龙葵、空心菜、苣菜、芥菜和鱼腥草6种植物对土壤中十溴联苯醚(BDE-209)的生理响应及其修复效果。结果表明,在BDE-209污染条件下,供试植物体内丙二醛(MDA)含量升高,表明植物受到一定的毒害作用,而在植物抗逆境机制作用下,植物体内可溶性蛋白质含量升高,超氧化物歧化酶(SOD)活性下降;在供试植物生物量方面,BDE-209对龙葵、空心菜和狼尾草地上部有促进作用,而对苣菜、芥菜具有一定的抑制作用;6种修复植物体内均检测出BDE-209,且地上部与根部BDE-209含量具有显著差异,其中狼尾草根部干重含量高达16.93mg·kg-1;修复60d后,土壤中BDE-209含量均有一定程度的下降,最高去除率可达40.44%,且根际土与非根际土BDE-209去除率有显著差异。修复效果依优劣次序为狼尾草>龙葵、空心菜>鱼腥草>芥菜>苣菜。     

Pb胁迫对红椿（Toona ciliata Roem）生长发育及Pb富集特性的影响

采用盆栽试验研究了酸性紫色土、钙质紫色土和冲积土上生长的一年生红椿实生苗暴露在不同浓度Pb胁迫(O、200、450mg·kg-1和2 000 mg·kg-1)条件下的叶长、叶面积、生物量、各器官Pb含量特征和富集程度,并分析了红椿对Pb污染的耐性和转移效率.3种土壤下红椿都能生长,但相同浓度Pb胁迫下其在钙质紫色土中生长状况最佳,在冲积土中生长状况最差.随Pb浓度增大红椿叶片生长受到明显抑制,当土壤中Pb浓度在2 000 mg· kg-1时,其叶长和叶面积与对照差异极显著(P＜O.01);Pb胁迫使得红椿根茎比发生明显的变化,还加大其叶的凋落程度,同时整株生物量随着Pb胁迫浓度的增大呈极显著降低趋势(P＜0.01),但在土壤Pb浓度最大时其生物量仍达到对照的81.47％以上.红椿体内Pb含量与土壤Pb浓度成正相关(P＜0.01),其6个器官中细根Pb含量最高,粗根次之,而地上部分的Pb含量较低且差异不大.红椿耐性指数值在0.67～1.06之间,表现为随Pb胁迫浓度增大,其耐性呈下降趋势.红椿富集系数与转移系数都较小且小于0.3.这些结果表明,红椿能在Pb污染较严重的土壤中较好的生存,可作为Pb污染区域潜在的土壤修复树种.     

Pb胁迫对欧美杂交杨（Populus deltoides×Populus nigra）生物量分配格局及其Pb富集特性的影响

采用速生树种修复重金属污染土壤的方法近年来受到越来越多关注,但已有结果存在很大不确定性。为了解杨树在不同Pb胁迫条件下生长响应和Pb富集效果,以长江上游两种典型土壤(酸性紫色土和钙质紫色土)为栽培介质,采用盆栽试验方法,研究了不同Pb浓度处理下(CK:0mg·kg-1;T1:200mg·kg-1;T2:450mg·kg-1;T3:2000mg·kg-1)欧美杂交杨(Populus deltoides×Populusnigra)生物量生产与分配格局以及Pb吸收、富集特性。两种土壤条件下杨树各器官生物量及总生物量均表现出随Pb胁迫程度的增加而降低的趋势,Pb胁迫条件下杨树生物量分配格局在钙质紫色土中表现为茎>粗根>叶>细根。相同浓度Pb处理条件下,单株杨树总生物量均表现为钙质紫色土大于酸性紫色土。随着Pb处理浓度的增大,杨树各器官Pb含量及积累量显著增加。Pb胁迫使杨树对Pb的富集系数逐渐增大而耐性系数逐渐减小。T3处理条件下杨树对Pb的富集系数在酸性紫色土中较大,且各处理条件下杨树对Pb的耐性系数均为酸性紫色土中较大。这些结果表明,高浓度Pb胁迫条件下酸性紫色土中的欧美杂交杨表现出较好的吸收和富集Pb的特性,这为Pb污染土壤的生物修复提供了一定的科学依据。     

黑麦草幼苗对镉耐性能力及吸收积累和细胞分布特点研究

通过盆栽试验研究了镉（Cd）胁迫下黑麦草（LoliumperenneL.）幼苗的耐性能力（包括生长反应和生理生化特性）以及对Cd的吸收、积累、分布特征。结果表明,当Cd浓度为10mg.kg-1时,黑麦草的生长和发育没有受到明显抑制（P〉0.05）,当Cd浓度为20、60、100mg.kg-1时,黑麦草生物量、叶绿素含量、根系活性都显著降低（P〈0.05）;超氧阴离子（O2-.）、MDA含量显著增加（P〈0.05）;SOD、POD活性先增加后降低。黑麦草体内Cd积累量随着Cd浓度增加而显著增加（P〈0.05）;Cd在亚细胞内积累量：F1（细胞壁）〉F3（可溶部分）〉F2（细胞器）。黑麦草在Cd浓度为10、20mg.kg-1时,富集系数〉1.0,对Cd有较强的富集能力,转移系数〈1,富集的Cd主要累积在根部,表明黑麦草能够有效富集土壤中的Cd,且富集的Cd主要积累在根部。     

在积累镉油菜后茬种植白菜可否减少其对镉的吸收?

Rapeseed (Brassica campestris L.), a Cd-accumulating crop, is effective in reducing plant-available Cd from soil. A pot experiment was conducted to test the hypothesis that the Cd uptake by Chinese cabbage (Brassica pekinensis Rupr.) grown in rotation with rapeseed would be reduced due to the efficient removal of bioavailable Cd from soil solution by the rapeseed crops. The Cd removal by shoot for the rapeseed cultivar Zhucang Huazi ranged from 0.24% to 0.99% in natural Cd-contaminated soil (soil A) and from 0.63% to 1.23% in artificial Cd-contaminated soil (soil B) during the growth period of 4–7 weeks; whereas that for the rapeseed cultivar Chuanyou II-93 ranged from 0.25% to 0.66% and from 0.38% to 1.02%, respectively. Chinese cabbage grown in the pots with soil A for five weeks after harvesting rapeseed exhibited a significantly lower Cd concentration compared to that grown in the control pots (uncropped with rapeseed). However, the rotation of rapeseed did not lower the Cd concentration of Chinese cabbage on soil B. Although an increase of Cd uptake was observed in the rapeseed cultivars with growth time, and the decrease of soil NH 4 OAc-extractable Cd was found only in the natural rather than artificial Cd-contaminated soil.     

镉污染土壤伴矿景天的萃取强化-螯合剂和植物激素的叶面调控

为提高Cd超富集植物伴矿景天(Sedum plumbizicola)的植物萃取能力,采用盆栽试验研究螯合剂乙二胺四乙酸(EDTA)和植物激素脱落酸(ABA)单独和联合作用的叶面调控对伴矿景天生长和Cd吸收转运的影响,并通过大田试验进行验证。结果表明:盆栽试验叶面喷施EDTA、ABA均能提高伴矿景天对Cd的转运,地下部至地上部的Cd转运系数为EDTA＞ABA,但叶面EDTA处理对生长旺盛期伴矿景天的生长有抑制。伴矿景天各部位Cd富集浓度差异很大,呈现新叶＞地下部＞茎＞老叶,新叶中Cd浓度是老叶的3.6~5.4倍,且主要富集在细胞壁和细胞器中,占总富集量的88%~94%。EDTA处理新叶细胞器中Cd浓度剧增,ABA处理新叶细胞壁中Cd浓度增加,ABA和EDTA联合使用可以缓解EDTA对生长的抑制,且更有利于Cd从根系向地上部转运。大田小区试验叶面诱导强化伴矿景天Cd萃取是可行的,ABA和EDTA联合处理显著增加伴矿景天总Cd积累量,增幅达到37.87%。研究结果为伴矿景天修复Cd污染土壤提供理论指导。     

Physiological responses of Quercus oleoides (Schltdl & Cham) to soils contaminated by diesel

ABSTRACT

Oil pollution is a worldwide threat to the environment that affects the development of plants. The effect of soil contaminated by diesel on the physiological responses of seedlings of Quercus oleoides was investigated in two independent experiments. We proposed that physiological performance will decrease when seedlings are exposed to higher concentration of contamination. At the first experiment, levels of pollution with diesel were of 0%, 5%, 10% and 15%, and 0%, 2% and 3.5% in the second one. In the first experiment, photosynthetic rate, stomatal conductance, transpiration and total chlorophyll of Q. oleoides were higher in the control seedling, and lower in treatments of pollution with 5%, 10% and 15% of diesel during 3 days of treatment. Only, seedlings in soil polluted with 5% of diesel survived up to 16 days; they showed a photosynthetic rate of 5 μmol m^?2 s^?1, which was lower than control seedlings (9 μmol m^?2 s^?1). This pattern was observed in stomatal conductance, transpiration and relative water content. Surprisingly, in the second experiment, seedlings showed a higher photosynthetic rate and growth at 2% of diesel-contaminated soil than control seedlings, a phenomenon known as hormesis. In both experiments, soil respiration was proportional to soils contaminated. We concluded that Q. oleoides is highly vulnerable in soils contaminated with above 5% of diesel, but it maintains its physiological activities in soils contaminated below 2%, suggesting that seedlings can grow under low concentration of diesel contaminant, and may be used in phytoremediation of soils with low concentrations of diesel contamination.     

土壤铅镉污染修复中植物修复技术的研究进展

近年来,由于工业"三废"治理不彻底、化肥农药的过量使用以及剩余污泥回用农田等原因,导致我国土壤重金属污染日趋严重。重金属无法被降解,易在土壤中累积,并通过生物富集和生物放大效应对环境和人类健康造成危害。土壤重金属污染修复与治理成为研究热点。重金属污染治理包括客土法、石灰改良法、化学淋洗法、植物修复等,这些方法各具特点,均有其适用范围,得到国内外学者的普遍关注。文章针对土壤铅镉污染的植物修复技术展开综述,并对可能影响植物修复的一些因素进行了介绍,最后对本领域的研究方向进行了展望,以期为同行业的从业者提供一定的借鉴。     

易降解有机物及其施加方式对高粱吸收镉的影响

为探明易降解有机物及其施用方式对高粱吸收镉的强化效应,通过盆栽试验探讨了2 mmol·kg~(-1)草酸(OA)、2 mmol·kg~(-1)柠檬酸(CA)和1 g·kg~(-1)水溶性有机肥(DOF)分次(1～4次)施加对土壤中镉(Cd)的活性、高粱(Sorghum bicolor L.)生长及对Cd吸收的影响。结果表明:施加OA、CA和DOF提高了土壤中Cd的活性,且OA、CA分4次施加和DOF 1次施加时,土壤中DTPA-Cd含量最高,分别比CK显著增加了11%、30%和29%;OA、CA和DOF 1次施加对高粱生物量无显著影响,分2次施加则显著抑制了高粱生长,其中DOF处理的生物量较CK下降38%;OA、CA和DOF分2～3次施加促进了高粱对Cd的吸收,高粱根部、地上部中的Cd含量及富集系数显著高于CK;OA、CA分3次施加和DOF 1次施加时,高粱地上部分Cd积累量分别比CK显著增加了17%、30%和31%。总体来看,分3次施加CA对土壤Cd活化及高粱吸收Cd的效果最好。