挺水植物对城市河流中典型污水印记药物的去除

以AZM（阿奇霉素）、STZ（磺胺噻唑）、IBU（布洛芬）、DCF（双氯芬酸）、PRC（扑热息痛）、ATL（阿替洛尔）、CLF（氯贝酸）、CBM（卡马西平）和CAF（咖啡因）共9种WWMPs（wastewater-marking pharmaceuticals,污水印记药物）为目标物,采用HPLC-MS/MS检测方法,通过室内河流模拟系统,研究3种挺水植物组合（旱伞草+灯芯草、菖蒲+灯芯草、旱伞草+菖蒲）的人工生态系统在不同介质（水相、泥相、水生植物）中WWMPs的变化特性及对常规污染物（如COD_Cr、NH₃-N、TP、TN）的去除效果,并运用物料衡算等手段计算目标物的实际去除率.结果表明:3种挺水植物组合的人工生态系统对4种常规污染物的去除效果较为明显,COD_Cr、NH₃-N、TP、TN去除率范围分别为39.7%~47.8%、88.2%~99.4%、39.1%~58.1%和49.1%~58.5%;与无植物系统相比,挺水植物组合的人工生态系统对水相中药物有明显的去除效果,尤其是对CBM、IBU和DCF,最大去除率均在54.0%以上;旱伞草+菖蒲组合的人工生态系统对水相中CAF、CBM、CLF、DCF、IBU和STZ的去除效果较好,去除率为51.6%~87.7%;3种挺水植物组合的人工生态系统对泥相中WWMPs的去除效果大小依次为菖蒲+灯芯草>旱伞草+菖蒲>旱伞草+灯芯草;不同挺水植物组合的人工生态系统对WWMPs的富集特性不同,9种WWMPs吸收效果大小依次为CBM > CLF > CAF > IBU > DCF > ATL > PRC > AZM > STZ;3种挺水植物组合的人工生态系统对WWMPs的实际总去除率大小依次为菖蒲+灯芯草>旱伞草+菖蒲>旱伞草+灯芯草.研究显示,挺水植物组合的人工生态系统可以有效地去除城市河流中WWMPs及常规污染物,能作为净化水质、改善城市河流水环境的一种有效手段.      

多种湿地植物组合对污水中氮和磷的去除效果

通过室内静水实验,研究了再力花(Thalia dealbata)、鸢尾(Iris tectorum)、菖蒲(Acorus calamus)、茭白(Zizania aquatica)、睡莲(Nymphaea tetragona Georgi)、大聚藻(Myriophyllum aquaticum)、马蹄莲(Zantedeschia aethiopica Spreng)7种不同生态型的湿地植物进行镶嵌组合后各组合对水体中氮、磷的去除效果.结果表明,不同生态型的湿地植物组合对污水中氮和磷的去除效果较好,8种组合中对总氮和氨氮去除效果最好的组合为睡莲+再力花(S+Z)和睡莲+马蹄莲+茭白+菖蒲(S+M+J+C),最大去除率分别为92.29%和95.50%.对总磷的去除效果最好的组合为睡莲+再力花+鸢尾(S+Z+Y),较无植物对照组的最大净化率提高了43.73%.不同水生植物组合后对氮、磷的净化效果差异较小,种湿地植物组合对总氮、氨氮和磷的去除率范围分别为83.19%～92.29%、86.50%～95.50%和85.67%～99.87%.运用隶属函数进行综合评价,筛选出对污水中氮和磷净化能力较强的组合为:睡莲+再力花(S+Z)、睡莲+马蹄莲+茭白+菖蒲(S+M+J+C)、睡莲+再力花+鸢尾(S+Z+Y)及睡莲+再力花+茭白+菖蒲(S+Z+J+C).     

Microbial community variation in phytoremediation of triazophos by Canna indica Linn. in a hydroponic system

Phytoremediation of triazophos (O,O-diethyl-O-(1-phenyl-1,2,4-triazole-3-base) sulfur phosphate, TAP) pollution by Canna indica Linn. in a hydroponic system has been well studied, whereas the microbial mechanism on TAP degradation is still unknown. The variation in microbial community compositions was investigated by analyzing phospholipid fatty acids (PLFAs) profiles in microbes under TAP exposure. The TAP exposure resulted in an increase in proportions of fatty acid 16:0 and decrease in fatty acid 18:2ω9,12c, indicating that TAP may stimulate the reproduction of microorganisms and inhibit the growth of fungi to some degree. Significant correlation was found between the ratio of fungi to bacteria and TAP removal (r 2 = 0.840, p 0.01). In addition, the microbial community in the phytoremediation system with C. indica was dominated by Gram negative bacteria, which possibly contributed to the degradation of TAP. These results indicated that TAP might induce the colonization of bacteria in the hydroponic system planted with C. indica, and lead to a discrimination of microbial community, which might be one of the mechanisms on TAP dissipation in phytoremediation system.     

Piriformospora indica confers cadmium tolerance in Nicotiana tabacum

Piriformospora indica, a root-colonizing endophytic fungus of Sebacinales, promotes plant growth and confers resistance against biotic and abiotic stresses. In order to confirm the influence of P. indica on growth, proline, malondialdehyde (MDA), chlorophyll, and cadmium (Cd) amounts in Nicotiana tabacum under Cd stress, hydroponics, pot and field trials were conducted. The results showed that P. indica can store Cd in plant roots and reduce leaf Cd content, reduce the concentration of MDA, and increase the proline and chlorophyll content and the activities of catalase, peroxidase, and superoxide dismutase under hydroponic Cd stress. RT-PCR analysis showed that the relative expression level of genes Gsh2, TaPCS1, oas1, GPX, and Hsp70 in colonized plants was 4.3, 1.4, 2.9, 1.7, and 6.9 fold higher than in un-colonized plants respectively. Cd exposure significantly reduced un-colonized plants'' agronomic traits compared to P. indica-colonized ones. Our results suggested that P. indica can sequester Cd in roots, so that much less cadmium was transported to leaves, and the increased concentrations of antioxidant enzymes, pigments and proline contents, as well as the higher expression of stress-related phytochelatin biosynthesis genes in P. indica-inoculated plants, may also serve to protect N. tabacum plants against oxidative damage, enhancing Cd tolerance.     

南京市铅锌矿采矿场土壤重金属污染评价及优势植物重金属富集特征

为了筛选可用于修复土壤重金属污染的植物材料,测定了南京市某铅锌矿采矿场土壤及样地内14种优势植物中Cd、Cr、Cu、Mn、Pb、Zn的含量,并分析了采矿场土壤重金属的污染状况和14种植物对这6种重金属元素的富集和转运能力.结果表明,矿区土壤中Cd、Mn、Zn、Pb的污染最为严重,单因子污染指数分别达到了45.71、11.68、10.40和4.46;样地的内梅罗综合污染指数为33.45,也达到重度污染级别.尽管各种重金属的含量不同,14种优势植物均表现出了较强的重金属耐受能力,其中井栏边草(Pteris multifida)和络石(Trachelospermum jasminoides)对6种重金属均表现出很高的富集能力.所有植物体内Zn含量均超出了正常范围,但仅马唐(Digitaria sanguinalis)对Zn的生物富集系数大于1,其他植物的重金属生物富集系数均小于1.14种植物对重金属的生物转移系数较高,其中菊芋(Helianthus tuberosus)和野菊(Dendranthema indicum)对6种重金属的生物转移系数均大于1.根据植物对重金属的吸收机制,可将14种植物分为3类:富集型植物,如菊芋(H.tuberosus)、野菊(D.indicum)、垂序商陆(Phytolacca americana)、爵床(Justicia procumbens)、马唐(D.sanguinalis)、山莴苣(Sonchus brachyotus)、龙葵(Solanum nigrum)和狗尾草(Setaria viridis);根部囤积型植物,如井栏边草(P.multifida)和络石(T.jasminoides);规避型植物,如一枝黄花(Solidago decurrens)、蛇莓(Duchesnea indica)、青绿苔草(Carex breviculmis)和贯众(Cyrtomium fortunei).     

五种水生植物对水中铀的去除作用

采用水培实验,研究了浮叶植物野生水葫芦(Eichhornia crassipes)、漂浮植物浮萍(Lemna minor L)、满江红(Azolla imbircata)、沉水植物菹草(Potamogeton crispus)、挺水植物空心莲子草(Alligator Alternanthera Herb)在初始铀浓度分别为0.15、1.50和15.00 mg·L^-1水中的生长状况及它们对水中铀的去除能力.结果表明,在21 d的水培试验期内,满江红对铀表现出了最强的抗性,0.15、1.50和15.00 mg·L^-1的铀对满江红的生长抑制率分别只有4.56%、2.48%和6.79%,而满江红对水中铀的去除率分别达到了94%、97%和92%.进一步的试验表明,每1 L水中种植7.5 g满江红,可以获得最大的铀去除率,将初始铀浓度为1.25、2.50、5.00和10.00 mg·L^-1的水体降至国家排放标准(GB 23727—2009)规定值(0.05 mg·L^-1)以下分别需要17、19、23和25 d.研究结果为进一步开展铀污染水体植物修复的研究打下了基础.     

湖南下水湾铅锌尾矿库优势植物重金属含量及富集特征

矿区废弃地优势植物调查与筛选是植物修复研究的重点.通过研究湖南下水湾铅锌尾矿库区土壤重金属含量,以及库区优势植物对Pb、Zn、Cd、Mn、Cu等重金属的富集能力与转移特征,筛选出适应该地区生态修复的先锋植物.结果表明,库区发现高等植物40种,40属22科,并筛选出15种优势植物.其中地枇杷地上部分Pb含量为正常含量上限值的4.01倍,转运系数达到3.91,富集系数达到14.4,可见地枇杷对Pb具有很强的转运能力与富集能力,因此地枇杷对库区污染土壤修复具有巨大潜力,需对其Pb富集能力作进一步研究.除地枇杷外,其余14种优势植物对尾矿库区重金属污染有较好的耐性,可作为下水湾尾矿库区生态修复的先锋植物.     

Responses of butachlor degradation and microbial properties in a riparian soil to the cultivation of three different plants

A pot experiment was conducted to investigate the biodegradation dynamics and related microbial ecophysiological responses to butachlor addition in a riparian soil planted with different plants such as Phragmites australis, Zizania aquatica, and Acorus calamus. The results showed that there were significant differences in microbial degradation dynamics of butachlor in the rhizosphere soils among the three riparian plants. A. calamus displays a significantly higher degradation efficiency of butachlor in the rhizosphere soils, as compared with Z aquatica and P. australis. Half-life time of butachlor degradation in the rhizospheric soils of P. australis, Z aquatica, and A. calamus were 7.5, 9.8 and 5.4 days, respectively. Residual butachlor concentration in A. calamus rhizosphere soil was 35.2% and 21.7% lower than that in Z aquatica and P. australis rhizosphere soils, respectively, indicating that A. calamus showed a greater improvement effect on biodegradation of butachlor in rhizosphere soils than the other two riparian plant. In general, microbial biomass and biochemical activities in rhizosphere soils were depressed by butachlor addition, despite the riparian plant types. However, rhizospheric soil microbial ecophysiological responses to butachlor addition significantly (P < 0.05) differed between riparian plant species. Compared to Z aquatica and P. australis, A. calamus showed significantly larger microbial number, higher enzyme activities and soil respiration rates in the rhizosphere soils. The results indicated that A. calamus have a better alleviative effect on inhibition of microbial growth due to butachlor addition and can be used as a suitable riparian plant for detoxifying and remediating butachlor contamination from agricultural nonpoint pollution.     

四种不同植物湿地对不同C/N比生活污水的净化效果与季节动态

进水浓度、C/N比、植物种类是影响垂直流型人工湿地对生活污水净化效果的重要因素.本文主要研究了菖蒲(Acorus calamus)、香蒲(Typha orientalis)、千屈菜(Lythrum salicaria)和水葱(Scirpus Validus)等4种植物湿地在不同碳添加及C/N比处理条件下对模拟生活污水的净化效果和季节动态.结果表明,4种湿地植物在不同C/N比(2.5∶1、5∶1和10∶1)进水条件下均能正常生长.在一个生长季内4种湿地植物对主要污染物的平均去除效率为:COD 63.41%~78.02%,TN 33.19%~52.86%,TP 52.64%~73.16%.当C/N为5∶1时,香蒲湿地的COD和TP去除效果最佳,而当C/N为2.5∶1时,菖蒲湿地的TN去除率最高.夏末秋初(7—9月)人工湿地的净化效果较好,而冬季(11月—翌年1月)去除效果明显下降.总体而言,合理地调控进水浓度、C/N比,选择最佳的湿地植物,可显著提高垂直流型人工湿地对生活污水的净化效果.     

芘胁迫对5种羊茅属植物根系分泌的几类低分子量有机物的影响

根系分泌物与有机污染物的植物修复过程密切相关,研究胁迫条件下不同修复潜力植物根系分泌物的释放特征有助于揭示植物修复的内在机制.借助根际袋土培试验研究了芘胁迫(10~160 mg·kg~(-1))下5种羊茅属植物在不同胁迫期(30~70d)时根系分泌物中几种低分子量有机物的释放特征.结果表明:1芘胁迫促进了根系对可溶性糖的分泌:随着胁迫水平的升高、胁迫期的延长,其分泌量呈"先升后降"变化趋势,胁迫水平为C3(40.36 mg·kg~(-1))、胁迫期为40 d时达到最大值;修复潜力越大,趋势越明显.2芘胁迫增强了根系对低分子量有机酸的释放,修复潜力越大,释放高峰值出现时的胁迫浓度越高,且主要以草酸、乙酸、乳酸和苹果酸为主(98.15%),但修复潜力较强物种的根系分泌物中也检测到微量反丁烯二酸.3芘胁迫对氨基酸的种类影响不大,但对分泌量影响较大:苏氨酸、丝氨酸、甘氨酸、丙氨酸的分泌量随着胁迫水平的升高而剧增;脯氨酸、羟脯氨酸和天冬氨酸对芘胁迫的响应近乎以功能群的形式参与植物修复过程,参与的组分越多,修复潜力越强.可见,芘胁迫下根系分泌物中可溶性糖、低分子量有机酸以及氨基酸的释放特征与植物自身的修复潜力有关;修复潜力越强,释放量越多且成分越复杂,并表现出更强的环境适应性及生理可塑性.     

生物炭对人工湿地植物根系形态特征及净化能力的影响

构建了菖蒲人工湿地,通过向人工湿地中加入小麦秸秆生物炭、芦苇生物炭及木屑生物炭以研究生物炭对人工湿地中植物根系形态、溶解氧及净化能力的影响.结果表明,加入3种生物炭能显著增加人工湿地中菖蒲根的总根长、总投影面积、总体积、总表面积、根尖数、分枝数和根干重以及人工湿地中的溶解氧含量(P0.05);其中加入木屑生物炭后,菖蒲根的根长、投影面积、表面积、总体积、根尖数、分枝数和根干重分别增加了96.1%、106.2%、185.6%、172.5%、75.3%、121.5%和84.9%.加入生物炭后,菖蒲根系形态与人工湿地中溶解氧含量、总氮去除率、总磷去除率和COD去除率间均显著正相关(P0.05).在水力负荷0.022 m3·(m2·d)-1时,加入木屑生物炭显著增加了人工湿地对总氮、总磷和COD的去除率(P0.05).木屑炭有效地促进了人工湿地中植物根系的生长,增加了人工湿地溶解氧含量,提高了人工湿地的净化能力.     

Root-associated (rhizosphere and endosphere) microbiomes of the Miscanthus sinensis and their response to the heavy metal contamination

The plant root-associated microbiomes, including both the rhizosphere and the root endosphere microbial community, are considered as a critical extension of the plant genome. Comparing to the well-studied rhizosphere microbiome, the understanding of the root endophytic microbiome is still in its infancy. Miscanthus sinensis is a pioneering plant that could thrive on metal contaminated lands and holds the potential for phytoremediation applications. Characterizing its root-associated microbiome, especially the root endophytic microbiome, could provide pivotal knowledge for phytoremediation of mine tailings. In the current study, M. sinensis residing in two Pb/Zn tailings and one uncontaminated site were collected. The results demonstrated that the metal contaminant fractions exposed strong impacts on the microbial community structures. Their influences on the microbial community, however, gradually decreases from the bulk soil through the rhizosphere soil and finally to the endosphere, which resulting in distinct root endophytic microbial community structures compared to both the bulk and rhizosphere soil. Diverse members affiliated with the order Rhizobiales was identified as the core microbiome residing in the root of M. sinensis. In addition, enrichment of plant-growth promoting functions within the root endosphere were predicted, suggesting the root endophytes may provide critical services to the host plant. The current study provides new insights into taxonomy and potential functions of the root-associated microbiomes of the pioneer plant, M. sinensis, which may facilitate future phytoremediation practices.     

常年淹水和干旱对三峡库区消落带菖蒲生长恢复的影响

菖蒲是三峡库区常见的一种湿生植物,本研究探讨了常年淹水对菖蒲生长恢复的影响,并分析了干旱对露水后菖蒲生长恢复的影响,为三峡库区消落带植被恢复物种的选择提供科学依据.分别于2009年9月和2010年9月前后2次将菖蒲(Acorus calamus L.)植株完全淹水,分别于翌年3、4、5月将植株露水(分别记为S1、S2和S3),2011年定期统计植株数和叶片数,测定叶长、叶宽.结果表明,淹水导致植株萌发数显著低于对照,且随着淹水时间增加植株萌发数呈显著降低趋势;淹水显著促进3月和4月露水植株叶片的伸长和形成,其叶长、叶片数、株叶长和总叶长显著高于对照,而5月露水植株的叶长、叶宽、叶片数、株叶长、总叶长和总叶片数均显著低于对照.随着淹水时间的增加露水后植株死亡数呈显著增大趋势,S1和S2组的叶长、叶宽显著增长,叶片数显著降低,而S3组植株叶长、叶宽、叶片数、株叶长、总叶长和总叶片数均显著降低.干旱导致对照、S1和S2组植株叶长、叶宽、株叶长、总叶长、叶片数和总叶片数均显著降低,植株存活数显著降低;干旱胁迫去除25 d后,对照、S1和S2组植株的叶片数分别增加了67.0%、66.7%和36.2%,且S1和S2组植株的株叶长、总叶长和总叶片数分别增加了48.2%、18.1%,66.7%、35.0%,75.0%、64.3%,差异显著(P<0.05).因此,菖蒲不仅对淹水的适应和耐受能力较强,而且露水后的生长恢复能力及对干旱的恢复能力也较强,可作为三峡库区消落带(特别是3月和4月露水区域)的恢复、重建物种.     

低温环境下人工湿地植物组配对养殖废水的处理效果研究

强化低温环境下人工湿地的污水处理能力,对于促进人工湿地的应用推广具有重要的意义。本研究利用绿狐尾藻(Myriophyllum aquaticum)和菖蒲(Acorus calamus L.)两种湿地植物,在室外低温环境下(＜15℃),研究人工湿地植物组配对不同负荷养殖废水的处理效应及关键影响因素。结果表明,在不种、单种和不同顺序混种绿狐尾藻(M.aquaticum)和菖蒲(A.calamus L.)处理下,菖蒲+绿狐尾藻组合湿地(AM)对TN、TP和COD去除率均为最高,在低负荷和高负荷环境下平均去除率分别为74.2%、71.3%、83.0%和67.3%、81.9%、75.3%。相较于空白对照和植物单种的湿地系统,植物混种系统的DO较高,且AM处理在低负荷和高负荷环境下均能保持较高的C∶N。根据Pearson相关性以及PCA分析,DO与TN、NH⁺₄-N去除率显著相关(P<0.05),C∶N与COD去除关联性最好。可见,菖蒲+绿狐尾藻植物组合可能通过改善DO和C∶N等湿地微环境条件来增强湿地对污染物的去除,能够作为低温环境下强化湿地对污染物去除的一种有效措施。     

Evaluation of antioxidant enzymes activities and identification of intermediate products during phytoremediation of an anionic dye (C. I. Acid Blue 92) by pennywort (Hydrocotyle vulgaris)

The potential of pennywort(Hydrocotyle vulgaris)for phytoremediation of C.I.Acid Blue 92(AB92)was evaluated.The efects of various experimental parameters including pH,temperature,dye concentration and plant weight on dye removal efciency were investigated.The results showed that the optimal condition for dye removal were pH 3.5 and temperature 25°C.Moreover,the absolute dye removal enhanced with increase in the initial dye concentration and plant weight.Pennywort showed the same removal efciency in repeated experiments(four runs)as that obtained from the first run(a 6-day period).Therefore,the ability of the plant in consecutive removal of AB92 confirmed the biodegradation process.Accordingly,a number of produced intermediate compounds were identified.The efect of treatment on photosynthesis and antioxidant defense system including superoxide dismutase,peroxidase and catalase in plant roots and leaves were evaluated.The results revealed a reduction in photosynthetic pigments content under dye treatments.Antioxidant enzyme responses showed marked variations with respect to the plant organ and dye concentration in the liquid medium.Overall,the increase in antioxidant enzyme activity under AB92 stress in the roots was much higher than that in the leaves.Nevertheless,no significant increase in malondialdehyde content was detected in roots or leaves,implying that the high efciency of antioxidant system in the elimination of reactive oxygen species.Based on these results,pennywort was founded to be a capable species for phytoremediation of AB92-contaminated water,may be efective for phytoremediation dye-contaminated polluted aquatic ecosystems.     

水培海马齿对海水菲污染修复作用的初步研究

采用水培法研究了海洋滩涂耐盐植物海马齿(Sesuvium portu lacastrum Linn.)对海水菲污染的修复作用.结果显示,实验4d后,不种植海马齿的对照组、种植海马齿的抑菌组和不抑菌组海水中菲浓度分别从0.988、0.942和0.957mg·L-1降至0.553、0.185和0.070mg·L-1,降低了44.0%、80.4%和92.7%;与对照组相比,抑菌组(T1)和不抑菌组(T2)海水中菲的去除率分别提高了36.4%和48.7%,不抑菌组又比抑菌组高12.3%.利用差减法计算的结果显示,在与自然水体接近的不抑菌条件下,菲的非生物损失、海马齿的作用和微生物的作用,三者对海水中菲浓度降低(92.7%)的贡献分别为44.0%、36.4%和12.3%,海马齿植株内菲的积累量则仅占海水中菲减少量的2.6%.研究表明,水培海马齿可明显提高菲污染海水中菲的去除率,其中,植物与微生物共同发挥着重要的作用,但植物积累不是海马齿修复海水菲污染的主要机制.     

厌氧环境下美人蕉根表铁膜对重金属积累转运的影响

根表铁膜作为污染物进入植物体内的门户,对植物修复重金属污染底泥起着重要作用.有机物降解消耗DO导致的底泥厌氧环境会显著影响根表铁膜的形成,并改变重金属的生物地球化学特征,从而影响重金属污染底泥的植物修复效果.为了探讨底泥厌氧环境中植物根表铁膜对重金属积累和转运的影响,采用向底泥中投加蔗糖模拟底泥厌氧条件的方法,测定不同底泥厌氧水平下挺水植物美人蕉（Canna indica）的生物量、根表铁膜和植物组织内重金属的含量.结果表明:①底泥厌氧环境不利于美人蕉对Cd、Cr、Cu、Ni、Pb和Zn的吸收,随着厌氧程度的增加,美人蕉对重金属的吸收量逐渐减少.②底泥厌氧环境能促进根表铁膜的形成及其对Cr和Ni的富集,重度厌氧环境中根表铁膜的含量为（10.40±0.30）g/kg（以根干质量计）,但厌氧环境抑制了铁膜对Cd、Pb和Zn的富集.③底泥厌氧环境不利于Ni从根表铁膜转运至植物组织,但轻度厌氧环境能促进Cr和Zn从根表铁膜转运至根系,且底泥厌氧环境对Cd、Pb和Cu的迁移转运无显著影响.研究显示,底泥厌氧环境促进了植物根表铁膜的形成,根表铁膜对重金属积累和转运的影响因底泥厌氧水平和重金属元素种类不同而不同.      

睡莲、梭鱼草对铜污染水体的修复效果研究

对水生植物睡莲(Nymphaea spontanea)、梭鱼草(Pontederia cordata)在5、15和25mg/L铜(Cu)质量浓度下的水体修复效果及生物富集作用进行了试验研究。结果表明,在实验条件下,30d后睡莲和梭鱼草对Cu全量的去除率分别为89%和58%。2种植物都能够用于修复Cu污染水体,且睡莲的修复效果和根部的Cu富集能力显著高于梭鱼草。初始浓度、修复时间及其交互作用对水体中Cu的去除具有极显著差异。植物鲜重增长率、修复效果、生物富集系数均随修复时间的延长和初始浓度的减小而增加。Cu溶解态及其全量具有较为一致的修复规律,去除率与修复时间呈高度相关的线性关系。今后应进一步探讨植物种植密度、修复时间和初始浓度对净化效果的综合影响。     

Effects of cowpea (Vigna unguiculata) root mucilage on microbial community response and capacity for phenanthrene remediation

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is normally limited by their low solubility and poor bioavailability. Prior research suggests that biosurfactants are synthesized as intermediates during the production of mucilage at the root tip. To date the effects of mucilage on PAH degradation and microbial community response have not been directly examined. To address this question, our research compared 3 cowpea breeding lines (Vigna unguiculata) that differed in mucilage production for their effects on phenanthrene (PHE) degradation in soil. The High Performance Liquid Chromatography results indicated that the highest PHE degradation rate was achieved in soils planted with mucilage producing cowpea line C1, inoculated with Bradyrhizobium, leading to 91.6% PHE disappearance in 5 weeks. In root printing tests, strings treated with mucilage and bacteria produced larger clearing zones than those produced on mucilage treated strings with no bacteria or bacteria inoculated strings. Experiments with ¹⁴C-PHE and purified mucilage in soil slurry confirmed that the root mucilage significantly enhanced PHE mineralization (82.7%), which is 12% more than the control treatment without mucilage. The profiles of the PHE degraders generated by Denaturing gradient gel electrophoresis suggested that cowpea C1, producing a high amount of root mucilage, selectively enriched the PHE degrading bacteria population in rhizosphere. These findings indicate that root mucilage may play a significant role in enhancing PHE degradation and suggests that differences in mucilage production may be an important criterion for selection of the best plant species for use in phytoremediation of PAH contaminated soils.     

蚯蚓、秸秆和柠檬酸对少花龙葵与翅果菊修复锌铅镉污染土壤的影响

外源物质调控和间作是提高重金属污染土壤植物修复效率的有效方法.采用盆栽试验研究蚯蚓、秸秆和柠檬酸对少花龙葵和翅果菊单作与间作修复Zn、 Pb和Cd复合污染土壤的影响.结果表明,蚯蚓对Zn、 Pb和Cd的富集系数(BCF)分别为0.07～0.13、0.10～0.26和5.64～15.52.土壤中添加秸秆能使蚯蚓生物量增加22.29%～223.87%、重金属含量下降8.15%～62.58%.蚯蚓对土壤重金属有效态含量的影响不大,但秸秆和柠檬酸对土壤重金属有效态含量分别表现为钝化和活化作用.蚯蚓对翅果菊的重金属含量影响不大,但会降低少花龙葵的重金属含量;秸秆对翅果菊重金属含量表现为抑制效应,但对少花龙葵Cd含量表现为促进效应;柠檬酸对少花龙葵重金属含量影响不大,但是会显著提高翅果菊的Pb含量.间作显著降低土壤重金属有效态含量,明显提高植物根的重金属含量,但对植物地上部重金属含量影响不大.植物对Zn、 Pb和Cd的总提取量主要表现为：翅果菊>间作>少花龙葵.添加蚯蚓可以使翅果菊Zn、 Pb和Cd总提取量分别提高12.49%、35.89%和29.01%;添加秸秆+蚯蚓可以使翅果菊Pb...