氯盐胁迫下氮素对西瓜根系生长的调控作用

为揭示氯盐胁迫下氮素对西瓜根系的调节机制和提供西瓜氯毒害调控理论依据,以西瓜为供试作物,采用土培试验,研究不同施氮量(0,0.1,0.15,0.2,0.25 g/kg)对氯盐胁迫下西瓜根系的影响,并应用主成分分析法对各施氮量下根系生长情况进行综合评价。结果表明,(1)与不施氮相比,施氮0.15 g/kg处理可使西瓜根系生物量、干物质累积量、脯氨酸含量、可溶性糖含量、根系活力分别显著提高58.83%、20.83%、98.33%、70.37%和29.44%,丙二醛含量显著降低40.30%,同时使总根长、总根表面积、根尖数、分枝数分别显著增加103.42%、46.41%、64.44%、87.80%,总根体积和总根系直径分别减少23.05%和40.15%。(2)在本试验氯盐胁迫条件下,施氮0.14~0.17 g/kg时西瓜具有较理想的根系构型和较高的根系活力。(3)根系分枝数、根系活力、总根体积、根尖数可作为氯盐胁迫下氮素对西瓜根系生长影响的综合评价指标,各施氮水平对氯盐胁迫的缓解效果表现为0.15 g/kg>0.20 g/kg>0.10 g/kg>0.25 g/kg。可见,在氯盐胁迫下,适量施氮有助于西瓜建立良好的根系构型,提高根系渗透物质含量,降低细胞渗透势,减少根系丙二醛含量,维持较强的根系活力,增加根系生物量和干物质,缓解高浓度氯盐对西瓜生长的抑制作用。     

离子液体1-丁基-3-甲基咪唑氯盐对溶菌酶结晶的影响

以亲水性离子液体1-丁基-3-甲基咪唑氯盐(BmimCl)为添加剂,研究离子液体对溶菌酶结晶的影响.分别考察了离子液体对溶菌酶晶体数量与尺寸、晶体形貌及蛋白质纯度的影响,并探讨了离子液体对结晶过程影响的作用机制.离子液体通过增大溶菌酶的溶解度和其自身低蒸气压两种途径,降低了溶菌酶在结晶过程中的过饱和度,更有利于晶体的成核和生长,得到更好的结果.如避免多晶态现象的发生,增大晶体的尺寸,降低溶菌酶样品纯度的要求.X-射线衍射分析表明,离子液体未改变晶体的晶型结构,但可提高晶体的衍射分辨率.     

钠盐和氯盐胁迫下胡杨木质部汁液ABA、离子浓度和叶片气体交换的变化

研究了渗透胁迫和盐胁迫下一年生胡杨(Populus euphratica Oliv.)幼苗的木质部汁液脱落酸(ABA)、离子浓度及叶片气体交换的变化。PEG 6000(溶液渗透势—0．24MPa)、50mmol／L含钠离子的盐溶液(NaNO3：NaHCO3：NaH2PO4=5：4：1,pH6．8,渗透势-0．24MPa)和50mmol／L含氯离子的盐溶液(KCl：NH4Cl=1：1,渗透势-0．24MPa)3种处理都显著降低了苗木的净光合速率(Pn)和蒸腾速率(TRN),但盐处理植株的TRN高于PEG处理的苗木。木质部汁液ABA的浓度在PEG处理后1h达到峰值,之后开始下降,降到对照水平后又逐渐回升。盐处理苗木的ABA也是在处理开始后就迅速升高,但之后ABA水平明显高于PEG处理的植株。结果显示,渗透胁迫和离子胁迫都能提高胡杨木质部汁液ABA的浓度：盐处理开始后ABA的迅速升高主要是渗透胁迫的作用,而此后离子胁迫(Na^ 和Cl^-)对ABA水平的提高具有重要作用。钠盐处理对胡杨净光合速率和蒸腾速率的抑制作用高于氯盐处理,其木质部汁液中较高水平的ABA和盐离子(Na^ 和Cl^-)是可能的原因。钠盐处理苗木的盐离子(Na^ 和Cl^-)水平高于氯盐处理,主要是由以下两方面的原因所致：(1)细胞膜上的Ca^2 被Na^ 所取代,增加了膜的透性;(2)胡杨根细胞液泡对Na^ 的区隔化能力较弱(与区隔Cl^-相比)。另外,盐胁迫下胡杨能保持对营养元素K^ 、Ca^2 和Mg^2 的吸收,这也是其抗盐性强的重要原因。     

青霉菌Penicillium janthinellum 菌株 GXCR的高抗重金属盐及其对Cu2+和 Zn2+离子吸收的特性

从广西某矿区污泥中分离了一株高抗Cu2 的真菌,编号为GXCR,根据形态和5.8SrRNA基因的内转录间隔子区的DNA序列同源性将其鉴定为Penicilliumjanthinellum。GXCR能够耐200mmolL–1的Cu2 ,在5mmolL–1Mn2 存在下,可在含800mmolL–1Cu2 的PDA上生长。在PDA培养基上,限制GXCR生长的其它金属盐的最小浓度(mmolL–1)依次为:Zn2 ,>1200;Al3 ,>500;Na ,>250;Mn2 ,>200;Cd2 ,50;Cr3 ,>60;Cr6 ,>3;Ni2 ,20;Pb2 ,50。对Cu2 、Cr6 、Pb2 和Zn2 ,的抗性是pH依赖性的,在pH3~7,随着pH的升高,其抗性急剧下降。在含3种金属盐混合物的PDL(未添加琼脂的PDA)中的GXCR生长的正交实验结果表明:金属盐之间存在显著的毒性协同效应;毒性协同效应强度不仅与盐的种类也与组成盐之间的浓度相关;GXCR有较高的抗3种金属盐混合物的能力。原子吸收测定结果表明:在含20mmolL–1Cu2 去离子水溶液中,未经NaOH预处理的自然菌体的Cu2 吸收量为38.1mgg-1干菌体,经200mmolL–1NaOH预处理的菌体的吸收量为76.9mgg-1干菌体;在含1200mmolL–1Zn2 的PDL(未加琼脂的PDA)中,接种分生孢子并连续培养7d后,菌体的Zn2 吸收量为258.3mgg-1干菌体。     

青霉菌Penicillium janthinellum菌株GXCR的高抗重金属盐及其对Cu2+和Zn2+离子吸收的特性

从广西某矿区污泥中分离了一株高抗Cu²⁺的真菌,编号为GXCR,根据形态和5.8SrRNA基因的内转录间隔子区的DNA序列同源性将其鉴定为Penicilliumjanthinellum。GXCR能够耐200mmolL^-1的Cu²⁺,在5mmolL^-1Mn²⁺存在下,可在含800mmolL^-1Cu²⁺的PDA上生长。在PDA培养基上,限制GXCR生长的其它金属盐的最小浓度(mmolL^-1)依次为:Zn²⁺,>1200;Al³⁺,>500;Na⁺,>250;Mn²⁺,>200;Cd²⁺,50;Cr³⁺,>60;Cr⁶⁺,>3;Ni²⁺,20;Pb²⁺,50。对Cu²⁺、Cr⁶⁺、Pb²⁺和Zn²⁺,的抗性是pH依赖性的,在pH37,随着pH的升高,其抗性急剧下降。在含3种金属盐混合物的PDL(未添加琼脂的PDA)中的GXCR生长的正交实验结果表明:金属盐之间存在显著的毒性协同效应;毒性协同效应强度不仅与盐的种类也与组成盐之间的浓度相关;GXCR有较高的抗3种金属盐混合物的能力。原子吸收测定结果表明:在含20mmolL^-1Cu²⁺去离子水溶液中,未经NaOH预处理的自然菌体的Cu2+吸收量为38.1mgg^-1干菌体     

离子液体1-丁基-3-甲基咪唑氯代盐对溶菌酶结晶的影响

以亲水性离子液体1-丁基-3-甲基咪唑氯盐(BmimCl)为添加剂,研究离子液体对溶菌酶结晶的影响.分别考察了离子液体对溶菌酶晶体数量与尺寸、晶体形貌及蛋白质纯度的影响,并探讨了离子液体对结晶过程影响的作用机制.离子液体通过增大溶菌酶的溶解度和其自身低蒸气压两种途径,降低了溶菌酶在结晶过程中的过饱和度,更有利于晶体的成核和生长,得到更好的结果.如避免多晶态现象的发生,增大晶体的尺寸,降低溶菌酶样品纯度的要求.X-射线衍射分析表明,离子液体未改变晶体的晶型结构,但可提高晶体的衍射分辨率.     

氯虫苯甲酰胺和甲维盐对草地贪夜蛾幼虫的毒力及解毒酶活性的影响

为了研究氯虫苯甲酰胺和甲氨基阿维菌素苯甲酸盐(甲维盐)对草地贪夜蛾Spodoptera frugiperda的毒杀作用及解毒机制,采用叶片浸渍法测定了2种杀虫剂对草地贪夜蛾3龄幼虫的LC_(10)、LC_(20)与LC_(50),并研究这2种农药的亚致死剂量(LC_(20))对幼虫的羧酸酯酶(CarE)、谷胱甘肽-S-转移酶(GST)、细胞色素P450(CYP450)3种主要解毒酶活性的影响。结果表明甲维盐对3龄幼虫的毒力更高,48 h时LC_(10)、LC_(20)、LC_(50)分别为0.005、0.007、0.013 mg/L。2种农药处理72 h内,幼虫的3种酶活力呈现不同的动态变化。氯虫苯甲酰胺对CarE活力表现先诱导后抑制的作用,在24 h时CarE活力最大(36.75 U/mg);甲维盐对CarE活力表现先抑制后诱导的作用,在72 h时CarE活力最大(42.44 U/mg)。2种农药对GST活性在72 h内的变化一致,均呈现"诱导-抑制-诱导"的规律。氯虫苯甲酰胺处理后CYP450活性与对照相比无显著差异;甲维盐处理36 h、48 h、72 h幼虫体内CYP450活性均显著低于对照。     

钠盐和氯盐胁迫下胡杨木质部汁液ABA、离子浓度和叶片气体交换的变化

研究了渗透胁迫和盐胁迫下一年生胡杨(Populus euphratica Oliv.)幼苗的木质部汁液脱落酸(ABA)、离子浓度及叶片气体交换的变化.PEG 6000 (溶液渗透势 -0.24 MPa)、50 mmol/L含钠离子的盐溶液 (NaNO3∶NaHCO3∶NaH2PO4=5∶4∶1, pH 6.8, 渗透势 -0.24 MPa)和50 mmol/L含氯离子的盐溶液 (KCl∶NH4Cl=1∶1, 渗透势 -0.24 MPa) 3种处理都显著降低了苗木的净光合速率(Pn)和蒸腾速率(TRN),但盐处理植株的TRN高于PEG处理的苗木.木质部汁液ABA的浓度在PEG处理后1 h达到峰值,之后开始下降,降到对照水平后又逐渐回升.盐处理苗木的ABA也是在处理开始后就迅速升高,但之后ABA水平明显高于PEG处理的植株.结果显示,渗透胁迫和离子胁迫都能提高胡杨木质部汁液ABA的浓度: 盐处理开始后ABA的迅速升高主要是渗透胁迫的作用,而此后离子胁迫(Na+和Cl-)对ABA水平的提高具有重要作用.钠盐处理对胡杨净光合速率和蒸腾速率的抑制作用高于氯盐处理,其木质部汁液中较高水平的ABA和盐离子(Na+和Cl-)是可能的原因.钠盐处理苗木的盐离子(Na+和Cl-)水平高于氯盐处理,主要是由以下两方面的原因所致: (1)细胞膜上的Ca2+被Na+所取代, 增加了膜的透性; (2)胡杨根细胞液泡对Na+的区隔化能力较弱(与区隔Cl-相比).另外,盐胁迫下胡杨能保持对营养元素K+、Ca2+和Mg2+的吸收,这也是其抗盐性强的重要原因.     

盐桦无菌材料的成功获得及其试管苗移栽定植成活的方法

目的:探讨获得盐桦无菌材料的最适灭菌方法和提高移栽定植成活率的关键性技术要点。方法:以新疆濒危植物盐桦当年生休眠枝条为材料,在适宜的培养基上筛选最适灭菌方法,继而以生长85~90d左右的组培试管苗为材料,探讨移植时期、温度、光照、水分、营养对成活率的影响。结果:采用半无菌水表面灭菌 75%酒精30s 0.1%升汞7~10min处理效果最好,污染率为13.3%。盐桦组培试管苗移栽定植中,以4月中旬~5月中旬成活率较高,平均成活率在95%以上。结论:研究筛选获得了盐桦的最适灭菌方法和盐桦组培试管苗移栽定植成活的适宜方法,为工厂化扩繁盐桦苗木创造了条件。     

新疆盐生植物耐盐基因NHX转化甘蓝型油菜及其耐盐性的初步研究

以甘蓝型油菜带柄子叶为转化受体,通过根癌农杆菌EHA105(Agrobacterium tumefaciens)介导将盐角草(Salicornia)的Na /H 反向运输体基因NHX导入新疆主栽油菜1khp11品系,获得了抗卡那霉素的再生植株,并对影响遗传转化的一些关键因素进行了研究。实验结果表明:带柄子叶在含有2,4-D的培养基上经过2d短时间的预培养后在菌液浓度OD600为0.3时在28℃摇床浸染15min时卡那抗性绿苗率可达10%￣12%;经过抗性植株的PCR及RT-PCR检测证明外源基因已整合到油菜基因组中,并通过表型实验证实由于外源基因的导入提高了植株的耐盐能力。     

Use of ants to monitor environmental impacts of salt spray from a mine in arid Australia

The habitat preferences, seasonal activity cycles and optimum sampling protocols of an ant community in the Australian arid zone were assessed by pitfall trapping. Diversity and abundance of ants peaked in the hotter summer months and varied greatly between different habitats. Sand dunes vegetated with tall perennial shrubs proved to be the most useful habitat for environmental monitoring using ants. Dominant and genera were suppressed by environmental stresses caused by salt spray from an underground mine. Remediation of the salt spray resulted in a general, yet inconsistent, recolonization of dominant ants at the expense of opportunistic genera. A greater understanding of the ecology of key ant species is required before ants can be used as unequivocal indicators of environmental condition at the Olympic Dam mine site.     

Environmental and biological controls on methyl halide emissions from southern California coastal salt marshes

Methyl bromide (CH₃Br) and methyl chloride(CH₃Cl) emission rates from southernCalifornia coastal salt marshes show largespatial and temporal variabilities that arestrongly linked to biological and environmentalfactors. Here we discuss biogeochemical linesof evidence pointing to vegetation as theprimary source of CH₃Br and CH₃Clemissions from salt marshes. Sediments andmacroalgae do not appear to be major producersof these compounds, based on observations thatthe highest fluxes are not inhibited by soilinundation; their emissions are not correlatedwith those of certain gases produced in soils;and emissions from mudflat- andmacroalgae-dominated sites are relativelysmall. In contrast, the seasonal and spatialvariabilities of methyl halide fluxes in thesesalt marshes are consistent with the productionof these compounds by vascular plants, althoughthe possibility of production by microflora orfungi associated with the salt marsh vegetationis not ruled out. Flux chamber measurements ofemission rates are largely correlated to theoverall plant biomass enclosed in the chamber,but appear also to be highly dependent on thepredominant plant species. Emission ratesfollow a diurnal trend similar to the trends ofambient air temperature and photosyntheticallyactive radiation, but not surface soiltemperature. Diurnal variabilities in thecarbon isotope compositions of CH₃Cl andCH₃Br and their relative ratios ofemissions are consistent with simultaneouslycompeting mechanisms of uptake andproduction.     

Development of mariculture and its impacts in Chinese coastal waters

China has a long history of aquaculture. Since the 1980s, mariculture has been considered by the government as an increasingly important sub-sector of aquaculture. Mariculture provides nutritional and economic benefits, and decreases the intensity of exploitation on declining wild living resources. China now has the highest mariculture production in the world. Kelp made up 50–60% the total Chinese mariculture production in 1967–1980. Production of Laminaria japonicaAresch, the leading species, reached 252, 907 t (dry wet) in 1980. The percentage of kelp production decreased after 1981 because of proportionally greater production of molluscs, shrimps and finfish. Marine finfish and mollusc production increased sharply after 1990. In 2001, the total mariculture production reached 11,315,000 t from a production area of 1,286,000 ha. The rapid development and changes in mariculture species have aroused increasing concern about maricultures impact on the coastal environment. The impact of coastal aquaculture, such as water quality deterioration and contaminants, will have a significant bearing on the expansion of mariculture. The key of improving and maintaining the long-term health of mariculture zones lies in adopting sustainable culture systems. It is imperative that the density of stocking fish and other economically important organisms such as oysters, and scallops, be controlled, in addition to restricting the total number of net-cages in the mariculture zones. The authors suggest moving rafts (cages) periodically and to development of a fallow system in which area fish culture will be suspended for 1–2 years to facilitate recovery of the polluted sediment. Moving fish culture offshore into deeper waters is also suggested. The authors also believe that large-scale seaweed cultivation will reduce eutrophication in coastal culture zones in China.     

Environmental impacts of gold mining in Essakane site of Burkina Faso

In this study, environmental impacts on air, water, and soil pollution caused by the exploit of Essakane gold mine, which is located in North Eastern part of Burkina Faso were investigated. Analyses on drinking water were made in the laboratory to determine the concentration of essential chemicals used in gold mining. Dust fallouts have been measured to assess the level of air pollution. The results showed that exploiting of gold mine directly or indirectly contributes to air pollution in Essakane district. The use of chemicals such as cyanide (industrial gold mining) and mercury (artisanal gold mining) to obtain the gold from the ore constitutes a potential risk for the ecosystem, the local population's health, and livestock production. The results also showed that there is a significant degradation of natural landscape and topography of the soil by open-pits mining (industrial mine) and holes dug by artisanal miners.     

Environmental and human health impacts of growing genetically modified herbicide-tolerant sugar beet: a life-cycle assessment

There is ongoing debate concerning the possible environmental and human health impacts of growing genetically modified (GM) crops. Here, we report the results of a life-cycle assessment (LCA) comparing the environmental and human health impacts of conventional sugar beet growing regimes in the UK and Germany with those that might be expected if GM herbicide-tolerant (to glyphosate) sugar beet is commercialized. The results presented for a number of environmental and human health impact categories suggest that growing the GM herbicide-tolerant crop would be less harmful to the environment and human health than growing the conventional crop, largely due to lower emissions from herbicide manufacture, transport and field operations. Emissions contributing to negative environmental impacts, such as global warming, ozone depletion, ecotoxicity of water and acidification and nutrification of soil and water, were much lower for the herbicide-tolerant crop than for the conventional crop. Emissions contributing to summer smog, toxic particulate matter and carcinogenicity, which have negative human health impacts, were also substantially lower for the herbicide-tolerant crop. The environmental and human health impacts of growing GM crops need to be assessed on a case-by-case basis using a holistic approach. LCA is a valuable technique for helping to undertake such assessments.     

转基因植物的环境生物安全：转基因逃逸及其潜在生态风险的研究和评价

转基因作物的商品化生产和大规模环境释放在带来巨大利益的同时,也引起了全球对其生物安全问题的广泛关注和争议,其中转基因通过花粉介导的基因漂移逃逸到非转基因作物及其野生近缘种,进而导致的潜在环境和生态风险就是备受争议的生物安全问题之一。转基因植物的环境生物安全涉及两方面关键问题：如何科学评价转基因植物商品化种植以后带来的环境和生态影响;如何利用环境生物安全的研究成果来制定科学有效的风险监测和管理措施。对转基因逃逸及其潜在生态风险的科学评价应包括三个重要环节：（1）检测转基因的逃逸的频率;（2）检测转基因逃逸后的表达和遗传规律;（3）确定逃逸后的转基因对野生近缘种群体适合度的影响及其进化潜力,本文将围绕对转基因逃逸及其潜在环境风险的科学评价,以转基因水稻为案例来对转基因逃逸带来生态影响的研究好评价的进展进行简要介绍,并对目前依据风险评价研究成果制定的各种管理策略进行了讨论。只有提高对转基因生物环境安全研究和评价的水平,并制定有效的风险监测和管理措施,才能为我国转基因技术的发展和转基因产品的商品化应用保驾护航。     

Effect of farming practices for greenhouse gas mitigation and subsequent alternative land use on environmental impacts of beef cattle production systems

This study evaluated effects of farming practice scenarios aiming to reduce greenhouse gas (GHG) emissions and subsequent alternative land use on environmental impacts of a beef cattle production system using the life cycle assessment approach. The baseline scenario includes a standard cow–calf herd with finishing heifers based on grazing, and a standard bull-fattening herd using a diet mainly based on maize silage, corresponding to current farm characteristics and management by beef farmers in France. Alternative scenarios were developed with changes in farming practices. Some scenarios modified grassland management (S1: decreasing mineral N fertiliser on permanent grassland; S2: decreasing grass losses during grazing) or herd management (S3: underfeeding of heifers in winter; S4: fattening female calves instead of being reared at a moderate growth rate; S5: increasing longevity of cows from 7 to 9 years; S6: advancing first calving age from 3 to 2 years). Other scenarios replaced protein sources (S7: partially replacing a protein supplement by lucerne hay for the cow–calf herd; S8: replacing soya bean meal with rapeseed meal for the fattening herd) or increased n-3 fatty acid content using extruded linseed (S9). The combination of compatible scenarios S1, S2, S5, S6 and S8 was also studied (S10). The impacts, such as climate change (CC, not including CO₂ emissions/sequestration of land use and land-use change, LULUC), CC/LULUC (including CO₂ emissions of LULUC), cumulative energy demand, eutrophication (EP), acidification and land occupation (LO) were expressed per kg of carcass mass and per ha of land occupied. Compared with the baseline, the most promising practice to reduce impacts per kg carcass mass was S10 (all reduced by 13% to 28%), followed by S6 (by 8% to 10%). For other scenarios, impact reduction did not exceed 5%, except for EP (up to 11%) and LO (up to 10%). Effects of changes in farming practices (the scenarios) on environmental impacts varied according to impact category and functional unit. For some scenarios (S2, S4, S6 and S10), permanent grassland area and LO per kg of carcass decreased by 12% to 23% and 9% to 19%, respectively. If the ‘excess’ permanent grassland was converted to fast-growing conifer forest to sequester carbon in tree and soil biomass, CC/LULUC per kg of carcass could be reduced by 20%, 25%, 27% and 48% for scenarios S2, S4, S6 and S10, respectively. These results illustrate the potential of farming practices and forest as an alternative land use to contribute to short- and mid-term GHG mitigation of beef cattle production systems.     

氟的环境地球化学行为及其对生态环境的影响

近几十年来,氟的区域性环境地球化学异常和人为环境污染所导致的植物和人体氟暴露现象引起了广泛关注,世界各国学者对不同环境介质中氟的地球化学行为进行了较为深入的研究,但仍然存在诸多争议和不确定性.本文回顾了近些年来有关氟在大气、水、土壤中的来源、数量、存在形态、迁移转化和控制因素等方面的研究成果,以及氟的地球化学行为与植物和人体氟暴露的关联性,并提出了未来有关氟的环境地球化学行为研究应优先考虑的几个方向.     

Intertidal ecology and potential power impacts, Bay of Fundy, Canada

A large-scale tidal power project in the upper reaches of the Bay of Fundy would cause major changes in the tidal elevations of the headpond which would have a pronounced effect on intertidal ecology. The new mean low water level would be, on average, slightly above the present mean sea level whilst the new mean high water level would drop about 0.7 m. This would result in a much compressed intertidal zone. Mud and sand flats, below the present mean sea level, would be converted to sub-tidal habitat, whilst the high saltmarsh, flooded at present only on the highest spring tides, would become colonized by terrestrial vegetation. There would be major shifts in the relative importance of primary production by saltmarshes, intertidal microalgae and phytopiankton, but overall, it is likely that production would increase. Changes in both primary food sources and habitat area would affect the abundance of intertidal invertebrate organisms and the fish and migratory shorebirds that feed upon them.