贵州省新路卡林型金矿区苔藓植物多样性及重金属污染监测

研究发现新路卡林型金矿区苔藓植物有10科17属28种,其中,丛藓科有9种,占总数的32.14%,真藓科有8种,占总数的28.57%。真藓科和丛藓科为优势科。分析该卡林型金矿区4个生境的β多样性,发现废石区—废渣区与相对污染区—清洁区的β多样性指数差异最大,苔藓群落结构差异性最大,相似性成分最低。测定该矿区苔藓植物及相应基质的重金属元素Pb、Zn、Cu、Cd、Hg、As含量,发现这些重金属元素含量呈现了一定的规律性,即：废渣区>废石区>相对污染区>清洁区,这可能与金矿的开采和冶炼有密切联系。因此,通过对苔藓植物的深入研究,可用以监测卡林型金矿区重金属污染情况。     

贵州木油厂汞矿区4种藓类植物及其基质中重金属元素分析

通过对贵州木油厂汞矿区4种藓类植物(真藓、卵蒴真藓、羽枝青藓和圆枝粗枝藓)及其生长基质中的Cu、Zn、Ca、Mg、Cd、Pb、Hg、As 8种元素进行测定分析,以揭示藓类植物与生长基质中重金属元素及其污染程度的关系.结果表明:(1)贵州木油厂汞矿区藓类植物生长基质中Cu、Hg和As元素的平均含量分别是相应国标值的1.29倍、300倍和1.69倍,说明该矿区已受到Cu、Hg和As的污染,且Hg污染特别严重.(2)羽枝青藓的As、Zn、Cd和Pb含量均最高,圆枝粗枝藓的Cu、Ca、Mg和Hg含量均最高,对重金属具有较强的耐受性.(3)羽枝青藓和圆枝粗枝藓对Zn均强烈富集,其富集系数分别为6.14和3.364;羽枝青藓、卵蒴真藓和真藓对Pb均强烈富集,其富集系数分别为13.769、9.547和3.004;表明羽枝青藓对Zn和Pb的富集能力最强,可用于土壤Zn和Pb的污染治理.(4)4种藓类植物对Cu 的富集系数为0.915～1.184,卵蒴真藓和圆枝粗枝藓对Hg的富集系数分别为0.542和0.682,圆枝粗枝藓对As的富集系数为0.74,均为同一水平,表明4种藓类植物可指示其生长基质中Cu、Hg和As的含量.(5)元素间的相关分析显示,木油厂汞矿的Cd和As之间呈显著负相关(P＜0.05),表明两元素间有拮抗作用.     

贵州烂泥沟金矿区苔藓植物及其生态修复潜力分析

对世界级的大型卡林型金矿一贵州贞丰烂泥沟金矿区的苔藓植物进行初步调查。258份标本经鉴定共有15科37属81种。丛藓科（Pottiaceae）、真藓科（Bryaceae）、牛毛藓科（Ditrichaceae）和珠藓科（Bartramiaceae）植物适于在该区生长。对金灰藓（Pylaisiella polyantha）、黄色真藓原变种（Bryum pallescens var．pdlescens）、牛毛藓（Ditrichum heteromallum）、阔叶小石藓（Weisia planifolia）、短叶小石藓（Weisia semipatlida）、红毛细羽藓（Cyrio-hypnum versicolor）6种植物及其基质中的9种重金属元素进行测定,基质中As的含量达到222．378mg kg^-1,为国家3级标准（40mg kg^-1）的5．56倍;Hg的含量达23．516mg kg^-1,为国家3级标准（1．5mg kg^-1）的15．68倍,污染状况比较严重。通过对富集系数的分析来看,每种苔藓植物对至少3种以上的复合重金属有一定的富集能力,可以作为复合重金属含量较高矿山的生态修复与重建的先锋植物。     

黔西北两铜矿4种藓类植物重金属元素分析

坝口铜矿和长箐沟铜矿是峨眉山玄武岩型铜矿。利用3种光谱仪对卷叶丛本藓（Anoectangium thomso-niiMitt.）、酸土藓[Oxystegus cylindricus（Brid.）Hilp.]、硬叶扭口藓[Barbula rigidula（Hedw.）Mild.]和齿边异齿藓[Regmatodon serrulatus（Dozy et Molk.）Bosch et Lac.]及其基质中的Cu、Zn、Ca、Mg、Cd、Pb、Hg和As8种元素进行测定及分析,并计算出富集系数。结果表明,两铜矿Cu、Zn、Cd和Hg的背景值均超标,特别是Hg和Cu的平均含量分别是其标准值的10.28倍和2.33倍。长箐沟铜矿受Hg污染较重,坝口铜矿比长箐沟铜矿含Cu高。Cu-Cd、Zn-Ca、Ca-Pb和Hg-As均在0.05水平显著相关,Zn-Pb在0.01水平显著相关。Cu-Cd、Zn-Pb和Hg-As均产生协同效应。Zn-Ca和Ca-Pb均产生拮抗效应。富集系数有显著意义。4种藓类植物对Cu、Cd和Pb的吸收能力均是同一水平,可以作为指示植物,构成藓类植物组合来鉴别富集Cu、Cd和Pb的矿区。可利用卷叶丛本藓作为特征植物降低矿区As的污染。     

岩溶洞穴苔藓群落特征及其对重金属污染的指示意义: 以贵州织金洞为例

岩溶洞穴的开发与利用导致的重金属污染严重威胁洞穴环境及地下水, 因此对洞穴环境的监测具有重要的现实意义。本文通过对典型的暗河型溶洞贵州织金洞内的苔藓群落特征及其重金属污染状况进行研究, 拟揭示苔藓群落对洞穴重金属污染的指示意义。共发现苔藓群落类型34个, 苔藓植物种类20科33属49种, 含苔类8科8属12种, 藓类12科25属37种。优势科为丛藓科、凤尾藓科和提灯藓科, 物种占比率分别为16%、14%、14%。Hg污染超标倍数最高达59.45倍, 在距洞口不同深度均远高于Cr和Zn, 说明洞内Hg污染较为严重。苔藓群落指标随着重金属污染含量的上升总体呈下降趋势。所测定的重金属中基质Hg含量与苔藓群落指标的拟合程度最好, 与其对应的苔藓群落指标均呈显著负相关关系(P < 0.05), 说明苔藓群落特征能够很好地反映洞内Hg污染的变化趋势。RDA排序结果分析表明: 洞穴苔藓群落为适应低光度环境会表现出向光性运动、喜钙生基质、耐重金属等生理特征。蛇苔(Conocephalum conicum)植物体内的Hg含量与其基质Hg含量具有显著相关性(P < 0.05), 说明蛇苔受基质Hg污染影响较大。在今后的治理过程中, 可以考虑将蛇苔作为洞内环境的生物监测材料之一。     

贵州泥堡卡林型金矿区与非金矿区苔藓植物比较研究

首次报道了贵州普安县泥堡村韭菜烂滩的卡林型金矿区和非金矿区的苔藓。记录了泥堡韭菜烂滩卡林型金矿生苔藓3科8属15种,非金矿生苔藓9科15属20种。通过比较我们得到韭菜烂滩卡林型金矿区和泥堡非金矿区苔藓的相似性系数为11.4%。这表明这两个生境下的苔藓组成差异极大。在这个地区有13种苔藓植物(包括异芽丝瓜藓Pohlia leucostoma、卵蒴丝瓜藓P.proligera、长蒴藓Trematodon longicollis等)只生长在卡林型金矿上,这表明有一些苔藓植物适应卡林型金矿这种基质。也许,在泥堡地区某些苔藓植物的分布与卡林型金矿存在一定的关系。     

重金属在土壤生态系统中的富集及毒性效应

对清水塘重金属污染区土壤生态系统重金属的富集及毒性效应的研究结果表明,土壤中 主要富集的重金属元素为生物毒性较强的Cd、Hg、As以及具有一定毒性的Zn、Pb、Cu,平均综 合污染指数为640.大型土壤动物重金属含量的分析结果表明,重金属富集量随污染程度的 增加而增加,尤其某些巨蚓科种类对Cd表现高富集,富集系数为1196.通过染毒试验进一 步证明,土壤动物种类和数量随Cd浓度的增加而减少.同工酶分析表明,Cd对蚯蚓同工酶活性 有明显的毒性效应.污染区主要种植蔬菜作物,而重金属在蔬菜体内的富集量也随污染 程度的增加而增加,其中蔬菜对Cd的富集有明显的品种间差异.     

金毛狗对重金属的富集特性的研究

为探讨金毛狗[Cibotium barometz(L.) J. Sm.]对重金属的富集能力,在广东省选取6个样点(南岭、南昆山、白云山、大岭山、梧桐山、西樵山)采集金毛狗的叶片、根状茎和根际土壤,采用ICP-MS测定9种重金属元素(Cr、Mn、Ni、Cu、Zn、As、Cd、Hg、Pb)的含量。结果表明,样地土壤已受到不同程度的重金属污染,土壤中Cd和Hg含量均高于广东省土壤背景值,分别为背景值的1.61~4.82倍和4.74~11.79倍。西樵山土壤中Cd含量最大,南岭土壤中Hg含量最大。在9种元素中,金毛狗对Hg的转运系数最高,达4.8,对Cd的富集系数最高,达2.2,Cu和Cd元素的转运系数和富集系数均大于1。这说明金毛狗对重金属元素的富集能力较弱而转运能力较强。     

湖南石门、冷水江、浏阳3个矿区的苎麻重金属含量及累积特征

对湖南省石门、冷水江、浏阳3个矿区土壤和苎麻体内重金属进行测定和分析。结果表明,石门雄黄矿区As污染严重,伴随Cd、Sb污染和轻微的Pb污染;冷水江锑矿区Sb为主要污染物,伴随Cd、As、Pb污染;浏阳七宝山矿区Cd污染严重,伴随Pb、Zn、Cu污染。15个采样点的苎麻群落生长繁茂,Sb和As在苎麻不同部位间的分布次序为叶片中含量最高,根茎中次之,其余重金属在部位间分布没有规律。所有采样点苎麻地上部的Cd含量比一般植物的Cd含量大2-10倍,As含量大9.9-147.5倍,Sb含量大1.2-338.4倍;Cd富集系数和转移系数最高值为2.07和3;As富集系数和转移系数最高值为1.04和12.42,Sb富集系数和转移系数最高值为1.91和9.04。3个矿区苎麻地上部生物量分别为3.47,14.3,15.7 t/hm²,地上部Cd、Pb、As、Sb、Zn和Cu的累积量分别高达0.11、1.17、0.72、7.97、6.71,1.69 kg/hm²,兼具一定的经济价值和观赏性,适合用作矿区重金属污染土壤的环境治理和修复。     

大兴安岭古利库砂金矿废弃地土壤重金属含量特征

矿产资源开采后形成大量废弃地已经成为土壤重金属污染主要来源之一。大兴安岭地区是我国砂金矿重要分布区,近百年的开采历史导致该地区遗留大面积的砂金矿采矿废弃地。然而,目前关于大兴安岭砂金矿废弃地土壤重金属污染情况的研究鲜见报道。本文以大兴安岭地区古利库砂金矿废弃地为对象,研究了砂金矿废弃地土壤重金属元素Hg、As、Pb、Cd和Cr的污染情况及分布特征,并采用内梅罗指数进行土壤重金属元素综合污染等级评价。结果发现:(1)与大兴安岭天然林相比,砂金矿废弃地土壤As、Cd和Cr含量分别增加83%、78%和101%;(2)在砂金矿废弃地不同位置,土壤Hg和Pb含量存在差异,而As、Cd和Cr含量差异不显著;(3)砂金矿废弃地土壤Hg、As、Pb、Cd和Cr含量均低于我国土壤环境质量一级标准值,土壤重金属污染综合评价等级未达到轻度污染等级。研究表明,大兴安岭砂金矿废弃地土壤重金属污染并不严重,今后在该地区砂金矿废弃地生态恢复建设中应该重点考虑土壤水分或养分限制问题。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.