Effect of phosphorus on arsenic accumulation in As-hyperaccumulator Pteris vittata L. and its implication

Pot experiment was conducted to understand the effect of phosphorus on arsenic accumulation in As-hyperaccumulator Chinese brake (Pteris vittata L.). It is shown that arsenic concentrations in the fronds and rhizoids, the arsenic bioaccumulation factor, and the total arsenic in the fronds were not influenced significantly under low levels of phosphorus (≤400 mg/kg) and increased sharply under high levels of phosphorus (＞400 mg/ kg). The discovery implies that the efficiency of arsenic removal in phytoremediation using the hyperaccumulating plant can be greatly elevated by the phosphorus addition at high rates. The interaction between the accumulation of phosphorus and that of arsenic in plant was stimulated mutually. The result represents that Chinese brake is a good material for plant physiologist to conduct comparative and mechanism studies on the uptake behaviors of phosphorus and arsenic, and phosphorus is also a potential accelerator for phytoremediation of arsenic-contaminated soils.     

Arsenic hyperaccumulator Pteris Vittata L. and its arsenic accumulation

An arsenic hyperaccumulator Pteris vittata L. (Chinese brake) was first discovered in China by means of field survey and greenhouse cultivation. Field survey showed that Chinese brake had large accumulating capacity to arsenic; the orders of arsenic content in different parts of the fern were as follows: leaves>leafstalks>roots, which is totally different from that of ordinary plants; bioaccumulation coefficients of the above ground parts of the fern decreased as a power function of soil arsenic contents. In the control of pot trials with normal unpolluted soil containing 9 mg/kg of arsenic, the bioaccumulation coefficients of the above ground parts and rhizoids of Chinese brake were as high as 71 and 80 respectively. Greenhouse cultivation in the contaminated soil from mining areas has shown that more than 1 times greater arsenic can be accumulated in the leaves of the fern than that of field samples with the largest content of 5070 mg/kg As on a dry matter basis. During greenhouse cultivation, arsenic content in the leaves of the fern increased linearly with time prolonging. Not only has Chinese brake extraordinary tolerance and accumulation to arsenic, but it grew rapidly with great biomass, wide distribution and easy adaptation to different environmental conditions as well. Therefore, it has great potential in future remediation of arsenic contamination. It also demonstrates important value for studies of arsenic physiology and biochemistry such as arsenic absorption, translocation and detoxification mechanisms in plants.     

Arsenic hyperaccumulator Pteris Vittata L. and its arsenic accumulation

An arsenic hyperaccumulator Pteris vittata L. (Chinese brake) was first discovered in China by means of field survey and greenhouse cultivation. Field survey showed that Chinese brake had large accumulating capacity to arsenic; the orders of arsenic content in different parts of the fern were as follows: leaves>leafstalks>roots, which is totally different from that of ordinary plants; bioaccumulation coefficients of the above ground parts of the fern decreased as a power function of soil arsenic contents. In the control of pot trials with normal unpolluted soil containing 9 mg/kg of arsenic, the bioaccumulation coefficients of the above ground parts and rhizoids of Chinese brake were as high as 71 and 80 respectively. Greenhouse cultivation in the contaminated soil from mining areas has shown that more than 1 times greater arsenic can be accumulated in the leaves of the fern than that of field samples with the largest content of 5070 mg/kg As on a dry matter basis. During greenhouse cultivation, arsenic content in the leaves of the fern increased linearly with time prolonging. Not only has Chinese brake extraordinary tolerance and accumulation to arsenic, but it grew rapidly with great biomass, wide distribution and easy adaptation to different environmental conditions as well. Therefore, it has great potential in future remediation of arsenic contamination. It also demonstrates important value for studies of arsenic physiology and biochemistry such as arsenic absorption, translocation and detoxification mechanisms in plants.     

南方典型稻田土壤-水稻系统环境质量评价

为研究南方典型区域稻田土壤—水稻系统中重金属含量,系统采集了江西省进贤县、金溪县、渝水区、高安市、安福县和兴国县等6个水稻主产区典型田块土壤、水稻和灌溉水,重点分析了土壤和水稻铅、镉、砷和汞含量及其土壤养分,并采用单因子污染指数和内梅罗综合指数对土壤—水稻系统中重金属含量进行评价。结果表明,研究区稻田土壤pH、有机质、总氮、总磷、总钾、碱解氮、有效磷和速效钾总均值分别为5.48、32.99 g/kg、2.06 g/kg、0.54 g/kg、16.04 g/kg、156.71 mg/kg、14.00 mg/kg和94.98 mg/kg。研究区土壤铅、镉、砷和汞含量总均值分别为35.46、0.18、7.21和0.17 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数为0.56,土壤环境质量等级为清洁;但渝水土壤镉含量为0.37 mg/kg,超过限量标准(0.30 mg/kg),土壤环境质量属于警戒状态。研究区糙米铅、镉、砷和汞的含量总均值分别为0.06、0.17、0.24和0.0086 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数均值为0.77,糙米环境质量等级为警戒限;但兴国和渝水糙米镉含量分别为0.22和0.35mg/kg,均超过限量标准(0.20 mg/kg),环境质量等级分别为警戒限和轻度污染。相关性表明,糙米镉与土壤镉和铅呈显著正相关,而与土壤砷呈显著负相关;糙米砷与土壤砷和有效磷呈显著正相关。总之,重金属镉是调查区域水稻安全性最主要的潜在污染元素,需重点关注兴国和渝水两地水稻食品安全。     

水铁矿促进湿地植物净化含砷微污染水源水的试验研究

为了研究水铁矿促进湿地植物净化微污染水体中砷的效果及机理,选用美人蕉,添加不同比例水铁矿的石英砂构建微型垂直流人工湿地,考察含砷微污染水连续漫灌条件下美人蕉根表铁膜中铁含量及砷在湿地基质和植物茎叶中的分布规律。结果表明:湿地基质中水铁矿的添加剂量在200 mg/kg以内,湿地基质吸附截留砷的能力随水铁矿添加剂量的增加而提高;超过200 mg/kg以后,增加水铁矿对湿地基质截留砷的能力影响不明显。美人蕉根表铁膜中的铁含量随湿地基质中水铁矿添加剂量(在50~1 200 mg/kg范围内)的增加而增加;渍水状态下的美人蕉净化含砷的微污染水,根表铁膜中铁含量在100 mg/kg左右,最有利于砷的吸收和最终去除。     

两种不同消解方法测定近海沉积物氮磷含量的比较

采用两种不同的消解方法—微波消解法和高压消解法,对近海沉积物中的总氮、总磷进行同时消解,并比较了测定结果.结果表明:高压消解条件下测定样品1和样品2总氮的相对标准偏差分别为7.7%和7.4%,总磷的标准偏差分别为3.9%和7.8%;微波消解条件下测定样品1和样品2总氮的相对标准偏差分别为9.4%和10.1%,总磷的相对标准偏差分别为6.9%和8.1%;两种消解条件下的总磷含量相差不大(样品1分别为0.460 mg/kg和0.454 mg/kg,样品2分别为0.449 mg/kg和0.439 mg/kg),但高压消解条件下的总氮含量(样品1为0.114 mg/kg,样品2为0.122 mg/kg)明显高于微波消解(样品1为0.088 mg/kg,样品2为0.092 mg/kg),且相对标准偏差较小.因此可以认为高压消解方法的精密度高于微波消解方法.     

Sedum alfredii H: A new Zn hyperaccumulating plant first found in China

Field survey and greenhouse experiments were carried out to identify and characterize zinc (Zn) uptake and accumulation by a new Zn hyperaccumulating plant species (Sedum alfredii Hance) native to China. Zinc concentration in the shoots of Sedum alfredii Hance grown on an ancient mined area ranged from 4134 to 5000 mg/kg, with a mean of 4515 mg/kg. It suggests that Sedum alfredii could not only grow on heavily Pb/Zn contaminated soils, but also could accumulate extraordinarily high concentration of Zn. Under nutrient solution culture conditions, Sedum alfredii Hance grew healthy at Zn supplying levels from 0.006 to 240 mg@L-1. Zinc concentration in the shoots increased with external Zn levels increasing. The Zn concentration and accumulation in the shoots reached the highest at Zn supply level of 80 mg/L, with 19.67 g/kg and 19.83 mg/plant, respectively. All the results showed that Sedum alfredii Hance is a new Zn hyperaccumulating plant. This provides a new plant material to explore mechanism of plant to hyperaccumulate Zn, and a potent new plant species to phytoremediate Zn contaminated soils.     

土壤加砷对魔芋砷的含量、吸收与分布的影响

为了认识土壤砷污染与植物砷含量的关系,进行土壤加砷盆栽魔芋试验.结果表明,本实验条件下,魔芋球茎和茎叶的砷含量范围分别为2.12～14.98和1.23～21.23μg g-1,均与土壤加砷量呈极显著的线性相关.在对照下,球茎砷含量高于茎叶,在土壤加砷下,茎叶的砷含量高于球茎.魔芋的富砷量与土壤加砷量呈极显著的线性相关,在低土壤砷水平下,魔芋球茎富砷量大于茎叶,高土壤砷水平下,魔芋茎叶的富砷量大于球茎.同对照相比,土壤加砷降低了魔芋球茎富砷量所占比例,增加了魔芋茎叶富砷量所占比例,低土壤砷水平下,球茎富砷量所占比例高于茎叶,高土壤砷水平下,茎叶富砷量所占比例高于球茎.魔芋对土壤加砷的利用量与土壤加砷量呈极显著的线性相关,魔芋对土壤加砷的利用率只有0.25‰～0.84‰.魔芋球茎和茎叶对砷的富集系数分别为0.03～0.13和0.07～0.13,同对照相比,土壤加砷降低了球茎的富集系数,增加了茎叶的富集系数,在对照下,球茎的富集系数高于茎叶,在土壤加砷下,茎叶富集系数高于球茎.总之,土壤加砷不仅显著增加了魔芋球茎和茎叶的砷含量,也改变砷在魔芋体内的分布格局,魔芋是吸收利用土壤砷能力弱的植物,魔芋通过将所吸收的砷转移到地上部分以适应砷污染土壤环境.     

大学生常用化妆品中砷含量的检测分析

目的:对高校学生常用各类型化妆品中砷含量进行调查分析。方法:新银盐法测定4种不同种类化妆品样品中砷含量,结果依据2007年版《化妆品卫生规范》(砷含量不得超过10 mg/kg)进行卫生学评价。结果:所检测的4类化妆品(防晒霜、润肤霜、粉底、面霜)中,砷含量在0.186 1~4.045 3 mg/kg之间,浓度依次为润肤霜>防晒霜>粉底>面霜。结论:本次实验所测定的化妆品样品中砷含量未超过国家标准。     

江西省稻米中总砷和无机砷含量的测定与分析

选取江西省10个县市的100份新收获稻米为实验材料,分别采用电感耦合等离子体质谱法和高效液相色谱-电感耦合等离子体质谱法,测定了稻米中的总砷和无机砷含量。测定结果表明,该方法线性方程和相关系数良好,稻米粉标准物质测定结果良好。100份稻米中的总砷含量变化为0.045~0.382mg/kg,均值为 0.170mg/kg;无机砷含量变化为0.000~0.180mg/kg,均值为 0.067mg/kg;单因素方差分析结果显示,江西省10个县市稻米中的总砷和无机砷含量之间均存在不同程度的差异性,其中无机砷含量的差异性最为显著。实验结果证实,稻米无机砷中三价As³⁺含量较高,约占无机砷含量的90%。美国环境保护署健康风险评估结果表明,江西省稻米中无机砷含量的暴露对人体健康没有风险。     

四川道地药材:“川麦冬”中铅、砷、汞的含量测定及安全性评价

用电感耦合等离子体质谱法测定四川三台县所产川麦冬药材中铅、砷、汞的含量并进行分析,结果表明:9批川麦冬中铅、砷、汞的含量范围分别为0.011～0.030、0.077～0.48和0.004 32～0.016 90 mg/kg,均低于《药用植物及制剂外经贸绿色行业标准》和《中国药典》(2010版)中限量标准,但川麦冬作为保健食品,砷含量有超标现象,有必要对川麦冬的生产按中药材生产质量管理规范(GAP)的要求进行规划和管理,以期为川麦冬的用药质量及评估提供参考.     

缺氧段碳源浓度对反硝化聚磷的影响

为了提高反硝化除磷工艺的脱氮除磷效率,以反硝化除磷污泥为研究对象,采用静态试验进行对比研究,考察碳源浓度对缺氧反硝化聚磷的影响.结果表明:当缺氧段初始碳源浓度为10.0 mg/L时,亚硝酸盐积累严重,反硝化聚磷受到抑制;当缺氧段初始碳源浓度由24.6 mg/L上升至176.8 mg/L时,随着碳源浓度的增加,反硝化速率...     

磷肥对闽楠苗木生长及叶片氮磷钾浓度的影响

为了确定闽楠苗木的适宜施磷量,测定了8个水平施磷(0、7.5、15、22.5、30、40、60、90 mg/株)处理下闽楠苗木的生长特性和叶片养分状况。结果表明:(1)随着磷素供应水平的升高,闽楠苗高和总生物量均呈先升高后稳定的趋势,而地径呈增长—稳定—降低的趋势,拐点磷素供应量为22.5 mg/株;(2)随着磷素供应量的增加,闽楠苗木叶片氮和磷含量呈升高趋势,而钾含量先升高后降低; 当供磷量大于22.5 mg/株时,生物量未发生显著变化,说明此时植株对氮磷钾为奢侈消耗;(3)闽楠苗木叶片氮磷钾的临界含量分别为16.04、1.36和21.93 g/kg,最适含量范围分别为16.04～27.45、1.36～3.01和21.93～36.40 g/kg。综合分析认为,对闽楠苗木的最适施磷量为22.5～30.0 mg/株。     

苦荞籽中黄曲霉毒素B1质量分数检测方法的研究

以西南山区主推马铃薯品种青薯9号原种为材料,采取4因素5水平二次正交旋转组合设计,研究种植密度,氮、磷、钾施用量对青薯9号产量、单株重与株高之间的综合效应,通过数学模型分析表明:种植密度、氮、磷、钾施用量单因子对产量的影响排序为:氮肥种植密度磷肥钾肥;对单株重的影响排序为:氮肥钾肥种植密度磷肥;对株高的影响排序为:种植密度氮肥钾肥磷肥。计算机频数分析表明:当种植密度为4 543～4 691株/666.7 m~2,尿素施用量为11.85～12.54 kg/666.7 m~2,过磷酸钙施用量为32.2～32.85 kg/666.7 m~2,硫酸钾施用量为37.415～42.08 kg/666.7 m~2时,青薯9号产量在1 900 kg/666.7 m~2以上,单株重在0.51 kg/株以上。     

氮磷水平对于油麦菜产量及其硝酸盐积累的影响

通过田间试验研究了不同氮磷水平对油麦菜产量和食用部分硝酸盐含量的影响.结果表明:氮磷投入量比高量施肥减少46.4%,油麦菜增产32.4%.适宜的氮磷投入量和施用比例是油麦菜高产的重要因素,油麦菜产量较高时氮的施用范围为180~270kg.hm-2,磷的施用范围为125~190kg.hm-2.油麦菜硝酸盐含量随氮素水平的提高呈递增趋势,适量磷素能够抑制硝酸盐的积累.     

植物修复重金属-有机物复合污染河道疏浚底泥的研究

针对目前国内普遍存在的排污河道污染问题,通过盆栽试验研究了玉米、印度芥菜、超积累油菜、紫花苜蓿在施用不同配比的排污河道疏浚底泥上对重金属-有机物复合污染的修复情况及超积累的机理.结果表明,随着底泥配比的增加,植物发芽率的抑止程度也增加;适应底泥中高浓度复合污染的植物,底泥施用能促进其生长,提高植物体内的叶绿素含量.植物体内积累的重金属Zn、Pb、Cd以生长在底泥与土壤比为2:1的印度芥菜为最大,分别为1 521 mg/kg、453 mg/kg和11.7 mg/kg;Cu、Ni积累量以生长于底泥中的玉米为最大,分别为128 mg/kg和89.1 mg/kg.在本实验条件下,底泥中有机物以种植玉米的底泥为最大,为76.89%.通过环境扫描电子显微镜及配套的能谱分析发现,重金属在植物体内的聚集存在;经X荧光光谱仪和X射线衍射仪分析,确证了配合体之间及重金属和配合体相互形成架桥而聚集成团,形成重金属结合物积累在植物体内,且在植物根部发现积累了Cu的有机氯化物.种植前后底泥的X射线衍射对比表明,种植后重金属的晶格结构和存在形态发生了变化.     

Endangered plants persist under phosphorus limitation

Nitrogen enrichment is widely thought to be responsible for the loss of plant species from temperate terrestrial ecosystems. This view is based on field surveys and controlled experiments showing that species richness correlates negatively with high productivity and nitrogen enrichment. However, as the type of nutrient limitation has never been examined on a large geographical scale the causality of these relationships is uncertain. We investigated species richness in herbaceous terrestrial ecosystems, sampled along a transect through temperate Eurasia that represented a gradient of declining levels of atmospheric nitrogen deposition--from approximately 50 kg ha(-1) yr(-1) in western Europe to natural background values of less than 5 kg ha(-1) yr(-1) in Siberia. Here we show that many more endangered plant species persist under phosphorus-limited than under nitrogen-limited conditions, and we conclude that enhanced phosphorus is more likely to be the cause of species loss than nitrogen enrichment. Our results highlight the need for a better understanding of the mechanisms of phosphorus enrichment, and for a stronger focus on conservation management to reduce phosphorus availability.     

不同收获期海州香薷铜吸收的动态变化规律

随着不同处理中Cu质量分数的提高,海州香薷植物体内Cu质量分数呈现2个斜率递增的阶段,海州香薷植株内Cu质量分数对外界Cu质量分数的响应曲线以0.02%为转折点,当Cu质量分数大于0.02%时曲线斜率显著增加。在开花初期,Cu400处理污染土壤中Cu清除量达到最大值27.2 mg/pot,其污染土壤重金属去除率仅为4.95%。而盛花期,各处理污染土壤中海州香薷植物内重金属含量均明显高于开花初期,Cu400处理污染土壤中Cu清除量达到最大值143 mg/pot,其污染土壤重金属去除率达26.0%,与开花初期差异显著(P<0.05)。     

A newly-discovered Cd-hyperaccumulator Solanum nigrum L.

Phytoremediation emerged in early the 1980s is animportant technology for remedying contaminated sites.One of the most promising phytoremediation technologiesis phytoextraction using hyperaccumulators to removeheavy metals from contaminated soils. The ter…     

邻株低磷竞争处理对杉木幼苗生长的影响

以南方林区广泛种植杉木无性系为研究对象,利用室内沙培模拟装置,设置缺磷(0 mg/kg KH2PO4)、低磷(6 mg/kg KH2PO4)和正常供磷(12 mg/kg KH2PO4)3个供磷水平,构建邻株磷竞争环境.结果表明:邻株低磷竞争处理可明显促进杉木苗高生长,但竞争条件下,缺磷处理抑制杉木苗高生长.不同邻株磷竞争处理条件下杉木地径生长差异未达显著水平.在邻株低磷竞争处理条件下杉木根系长度、表面积、直径、体积等形态指标增量最大.