砷污染土壤对不同品种水稻生长的影响

重金属如何影响水稻(Oryza sativa L.)的生长及产量一直是粮食生产中的研究重点。利用盆栽实验,首次比较了砷(As)对三个品系(杂交稻、常规稻和糯稻)共20个品种水稻生长的影响,以期选定适合在As污染区种植的水稻品种。结果显示,不同品系水稻在As污染土壤中的生长显著不同,杂交稻的生长优于糯稻和常规稻,但糯稻和常规稻差异不显著,表明杂交稻更适宜在砷污染土壤种植。同一品系内不同品种水稻的生长也有较大差异,杂交稻II优804的干物质积累量最高,每株达到0.055g。     

Diet and seasonal prey capture rates in the Mediterranean red coral (Corallium rubrum L.)

Gorgonians are passive suspension feeders, contributing significantly to the energy flow of littoral ecosystems. More than in active suspension feeders (such as bivalves, ascidians and sponges) their prey capture is affected by spatial and temporal prey distribution and water movement. Corallium rubrum is a characteristic gorgonian of Mediterranean sublittoral hard bottom communities. This study found a high variability in the annual cycle of prey capture rate, prey size and ingested biomass, compared to other Mediterranean gorgonians. Detrital particulate organic matter (POM) was found throughout the year in the polyp guts and constituted the main proportion of the diet (25–44%). Crustacean fragments and copepods (14–46%) accounted for the second major proportion, while invertebrate eggs (9–15%) and phytoplankton (8–11%) constituted the smallest part of the diet. To verify the importance of detrital POM in the energy input of this precious octocoral species, in situ experiments were carried out during the winter–spring period. The results confirm the importance of detrital POM as the main source of food for C. rubrum [0.13±0.04 μg C polyp⁻¹ h⁻¹ (mean±SD)]. This study also compares the prey capture rates of two colony size classes and two depth strata: Within the same patch, small colonies (<6 cm height) captured significantly more prey per polyp (0.038±0.09 prey polyp⁻¹ h⁻¹) than larger colonies (>10 cm high) (0.026±0.097 prey polyp⁻¹ h⁻¹) and showed a higher proportion of polyps containing prey (17% compared to 10%). Comparing colonies of similar size (<6 cm height) revealed that the colonies situated at 40 m depth captured significantly more prey (0.038±0.09 prey polyp⁻¹ h⁻¹) than the ones at 20 m (0.025±0.11 prey polyp⁻¹ h⁻¹). One pulse of copepods was recorded that constituted 16% of all captured prey during the 15-month period studied in one of the sampled populations. The data suggest that the variability of hydrodynamic processes may have a higher influence on the feeding rate than seasonal changes in the seston composition. The carbon ingestion combined with data on the density of the exploited population results in 0.4–9.6 mg C m⁻² day⁻¹. The grazing impact of current, heavily exploited and small-sized populations is comparable to that of larger Mediterranean gorgonians, suggesting that unexploited red coral populations may have a high impact compared with other passive suspension feeders.     

香樟根际土壤化感作用的初步研究

化感作用是农林复合生态系统中作物相互作用的重要方式,它有十分重要的经济、生态意义.该研究采用常规水浸提方法制备不同浓度的香樟(Cinnamomum camphora (L.) Presl.)根际土壤水浸提液,用生物测定法测定其对萝卜(Raphanus sativus L.)、红苋菜(Amaranthus mangosfanus L.)和荠菜(Capsella bursa-pastoris (L.) Medic.)的种子萌发和幼苗生长的化感作用.结果表明,浸提液浓度不同,其化感效应不同,受体植物不同,化感效应差别也较大,具体表现为,浓度较低时,化感作用较小,对萝卜根生长起促进作用,随着溶液浓度的增大化感抑制作用逐渐增强,大致表现出低促高抑的规律;萝卜受化感作用抑制作用较其他两种蔬菜小.通过研究可得出结论:香樟对蔬菜有较强的化感作用,香樟林地发展林-菜复合种植一定要选择合适的蔬菜种类和科学的管理措施.     

高效氯氟氰菊酯在玉米和土壤中的残留及消解动态

研究了济南和哈尔滨两年两地的玉米Zea maysL.经高效氯氟氰菊酯种子处理微囊悬浮剂拌种后,高效氯氟氰菊酯在玉米植株、籽粒和土壤中的最终残留量,以及在玉米植株和土壤中的降解动力学规律。结果表明,高效氯氟氰菊酯最终残留在植株、籽粒和土壤中的质量分数分别是〈0.005mg·kg-1、〈0.001mg·kg-1和≤0.053mg·kg-1;在土壤中的降解符合一级动力学方程,降解半衰期19.6～28.1d,消解速率哈尔滨慢于济南,这可能与土壤含水量和气温等有关。本研究为制定该农药在玉米上最大残留限量标准和合理使用准则以及风险评估提供了科学依据。     

Influence of lead on growth and nutrient accumulation in canola (Brassica napus L.) cultivars

Canola (Brassica napus L.) is commonly used as a hyper-accumulator for phytoextraction of heavy metals from soil and water. Like many other heavy metals, lead (Pb) contaminates soil, water and air and thus it is a great problem. This study was conducted to investigate toxic effects of Pb on growth and nutrient uptake in four canola cultivars. Each of four cultivars of canola (Con-II, Con-III, Legend and Shiralee) was subjected to four levels of Pb (0, 30, 60 and 90 mg Pb kg(-1) of soil) from lead chloride [PbCl2]. Due to Pb toxicity, plant growth was adversely affected and relatively a severe reduction in root biomass (45.7%) was recorded. The Pb accumulation increased both in shoot and root, the highest being in root. The uptake of different nutrients, i.e., N, P, K, Ca, Mg, Zn, Cu and Mn was reduced (38.4, 32.8, 33.1, 49.6, 7.78, 52.0, 42.6 and 45.9%, respectively) in the shoots and that of N, Fe, Zn, and Cu in the roots (48.5, 33.2, 24.3 and 44.8%, respectively) of all canola cultivars. The root K, P, Zn and Mn and shoot P, Mg and Fe contents were less affected, the concentration of Pb, Ca and Mg in roots of all cultivars. Among canola cultivars Con-II and Con-III performed better than Legend and Shiralee in terms of growth (26.03%) and nutrient accumulation. Overall, plant growth and nutrient accumulation in the canola cultivars was hampered due to the presence of Pb.     

Influence of selected insecticides on phosphatase activity in groundnut (Arachis hypogeae L.) soils

Selected insecticides, Chloropyrifos, Dichlorovos, Methyl parathion, Phorate and Methomyl, at concentrations ranging from 0 to 10 kg ha(-1) were tested for their non-target effects towards activity of phosphatases in two soils. In soil samples receiving 2.5 kg ha(-1) of the insecticides Dichlorovos, Phorate and Methomyl and also in soil samples receiving 5.0 kg ha(-1) of the insecticides, Chloropyrifos and Methyl parathion, the activity of phosphatase was significantly more at 20 days period of incubation and decreased progressively with increasing period of incubation.     

Multi-elemental compound-specific isotope analysis of pesticides for source identification and monitoring of degradation in soil: a review

Environmental Chemistry Letters - The transfer of pesticides from agricultural soils to food and drinking water is a major health issue. There are actually few robust methods to identify,...     

不同培养介质中纳米氧化铜对小麦毒性的影响

采用琼脂培养和水培方法比较了纳米氧化铜(CuONPs)在不同暴露介质中的环境化学行为及其对小麦根生长的影响,并探讨了不同培养介质对CuONPs植物毒性的影响机制.结果表明,琼脂介质相对水相(营养液)环境可以减少CuONPs的团聚,增强其分散性.在琼脂和水相中Cu离子溶出随CuONPs浓度变化规律存在明显差异,在50～1000mg CuONPs·L-(1以Cu计)范围内,CuONPs在琼脂中无论是Cu2+的溶出浓度还是溶出比率均低于其在水相中的值.CuONPs在不同介质中表现出显著的小麦毒性差异.琼脂培养下小麦根生长半抑制效应浓度EC50(以CuONPs浓度表示)为108mg·L-1,而在水培方式下为9.0mg·L-1,说明琼脂介质极大缓解了CuONPs引起的植物毒性.分析表明,Cu2+溶出浓度较CuONPs投放量与小麦根生长抑制效应之间存在更好的指数相关关系,这说明该研究体系下CuONPs小麦毒性主要是由纳米颗粒释放Cu2+引起的.此结论较好地解释了当培养介质从水相变成琼脂时,Cu2+溶出减少,纳米毒性降低的现象.该研究结果认为,当前国内外使用水培法获得的纳米材料植物毒性研究结果在外推至实际土壤状况时将高估其环境安全性风险,推荐使用琼脂作为纳米材料土壤环境风险评价的模拟介质.     

玉米根系形态对土壤Cd和芘复合污染的响应

植物根系在逆境胁迫下通过改变其形态及分布来适应不利的生长环境,根系的形态变化是植物适应外界环境（特别是土壤环境）的一个重要机制。采用盆栽模拟试验探讨了Cd＋芘复合污染对两种基因型玉米（Zeamays L.）（白玉米和黑玉米）根系形态学参数（根长、根表面积、根体积、根平均直径及不同根直径等级分布）的定量化影响。与对照未污染相比,Cd＋芘复合污染显著降低了白玉米和黑玉米茎叶和根的生物量,特别是根的生物量。Cd＋芘复合污染对白玉米生物量的抑制要比对黑玉米要灵敏。与未污染相比,Cd＋芘复合污染下白玉米和黑玉米的根长稍有增长,根表面积、根平均直径和根体积减小,但两处理间差异不显著。白玉米和黑玉米每一级根直径的根长在Cd＋芘复合污染和未污染处理间没有显著差异。白玉米和黑玉米〉0.60mm的根的根表面积在Cd＋芘复合污染下显著降低。此研究结果为重金属-多环芳烃复合污染土壤植物毒理效应和植物修复技术的进一步研究奠定基础。     

Effects of Arbuscular mycorrhizal fungi isolated from white clovers (Trifolium repens L) on soil bacteria and fungi

White clover potted experiments were performed to investigate the effects of seven indigenous arbuscular mycorrhizal fungi (AMF) communities isolated from different test plots subjected to long-term fertilisation on soil enzyme activities, number of soil bacteria and fungi. The results showed that the inoculation of arbuscular mycorrhizal fungi communities increased the mycorrhizal infection rate of the plants and promoted the growth of plants. The Mnp treatment was most effective. The shoot biomass, root biomass, potassium and nitrogen uptake of the white clover in Mnp treatment group were increased by 61.54%, 84.00%, 62.50% and 46.71% respectively, compared with those in non-inoculation treatment. The inoculation of AMF communities had little effect on the number of bacteria in the soil, but significantly increased the number of soil fungi. Mnk treatment group had the highest number of fungi in the soil, which was 9.91 times that of the non-inoculation treatment group. The catalase and dehydrogenase activities were both significantly improved in Mnp treatment by 28.12% and 205.38% respectively, compared with those of the control treatment (-M). The urease, invertase and cellulase activities reached the highest levels in the Mck treatment; they were increased by 142.79%, 41.17% and 77.62% respectively, compared with those of the control treatment. Pearson correlation analysis showed that the soil enzyme activity was not correlated with the mycorrhizal infection rate, but correlated with the spore number of the AMF community. The impact of AMF community on soil quality is important for us to understand the function of the ecosystems. Relevant study provides important guidance for maintaining the balance of the soil-plant system and the development of sustainable agriculture.     

固定化微生物对土壤中苯并芘的降解

研究了3株细菌与3株真菌对土壤中苯并芘（BaP）的降解动态,从中筛选出1株细菌（Bacillus sp.）和1株真菌（Mucor sp.）,并采用吸附法将混合菌固定在改性后蛭石上,研究了固定化混合菌对土壤中BaP的降解效果。结果表明：细菌中芽孢杆菌（Bacillus sp.,SB02）降解率最高,42 d对B[a]P的降解率为33.0%,降解速率也最快,1周可降解12.6%的BaP;真菌中毛霉（Mucor sp.,SF06）降解率最高,42 d对B[a]P的降解率为69.7%;以改性后蛭石为载体用吸附法制得的固定化混合菌,传质性能好,对BaP的降解率42 d可达95.32%,高于游离菌20个百分点。     

有机酸对潮褐土和红壤吸附Cu(II)的影响及其机制

采用吸附平衡法,研究了有机酸(草酸、柠檬酸)对潮褐土和红壤吸附Cu2+的影响及机制。结果表明,潮褐土、红壤对Cu2+吸附明显有异,潮褐土对Cu2+吸附量是红壤对Cu2+吸附量的5倍多。潮褐土对Cu2+的竞争吸附率随有机酸浓度升高而降低,当草酸、柠檬酸浓度为10 mmolL-1时,Cu2+吸附率均分别比对照的降低40%和70%以上。在低浓度条件下,红壤对Cu2+的竞争吸附率随有机酸浓度的提高而增加,当草酸、柠檬酸浓度分别超过1 mmolL-1和0.05 mmolL-1时,又随有机酸浓度的升高而降低。两种土壤对Cu2+次级吸附率随有机酸浓度升高而变化的规律与竞争吸附的一致。在相同有机酸浓度下,土壤对Cu2+的次级吸附率均比竞争吸附率的高。     

有机酸对潮褐土和红壤吸附Cu(Ⅱ)的影响及其机制

采用吸附平衡法,研究了有机酸(草酸、柠檬酸)对潮褐土和红壤吸附Cu2+的影响及机制.结果表明,潮褐土、红壤对Cu2+吸附明显有异,潮褐土对Cu2+吸附量是红壤对Cu2+吸附量的5倍多.潮褐土对Cu2+的竞争吸附率随有机酸浓度升高而降低,当草酸、柠檬酸浓度为10 mmol(L-1时,Cu2+吸附率均分别比对照的降低40%和70%以上.在低浓度条件下,红壤对Cu2+的竞争吸附率随有机酸浓度的提高而增加,当草酸、柠檬酸浓度分别超过1 mmol(L-1和0.05 mmol(L-1时,又随有机酸浓度的升高而降低.两种土壤对Cu2+次级吸附率随有机酸浓度升高而变化的规律与竞争吸附的一致.在相同有机酸浓度下,土壤对Cu2+的次级吸附率均比竞争吸附率的高.     

Effects of spatial variability and colony size on the reproductive output and gonadal development cycle of the Mediterranean red coral (Corallium rubrum L.)

Red coral (Corallium rubrum, L. 1758) is an over-exploited Mediterranean gorgonian. The gonadal development cycle of this gorgonian is examined at the Costa Brava (NW Mediterranean) taking into account for the first time colony size, depth and spatial horizontal variability. This study compares the gonad development and fertility in two colony size classes (colonies <6-cm height, and >10-cm height, both at 40–45-m depth), and two populations at different depths (16–18-m depth, and 40–45-m depth, both consisting of <6-cm high colonies) in a 15-month period. The fertility of seven size classes (<2 cm to >12 cm high colonies, in 2 cm intervals) was examined in the deep population, where large colonies were present. Furthermore, reproductive output was compared in 6 populations (distributed along more than 70-km coastline) one month before spawning (June). Red coral was found to be dioecious and gonochoric with a sex ratio of 1:1, which differs from other NW Mediterranean populations. On the other hand, fertility of different size classes indicates that small colonies of 2-cm height already produce gonads, which is in line with previous studies. Female and male polyp fertility and sperm sac size increase significantly with colony size [sperm sac diameter: 476±144 μm (mean±SD) and 305±150 μm in the >10-cm and <6-cm height colonies, respectively), whereas no significant effect on oocyte diameter was found (oocyte diameter: 373.7±18.7 μm). Depth staggered spawning, that is, an earlier release of gonads in the shallow populations, was observed in summer 2003, coinciding with the highest temperature gradient between shallow and deep water during the study period. Colonies of <6-cm height were significantly less fertile than colonies >12 cm, thus the recommendation of this study is that a minimum height should be incorporated into fishing regulations. The six studied populations at the Costa Brava showed a comparable reproductive potential, which demonstrates little variability within the homogenous population structure and range of size classes (due to overharvesting) found at the Costa Brava. The study of reproductive output is an important tool for ecosystem management, and this work recommends basing specific exploitation laws for distinctive populations on colony size, which is found to have a larger effect on reproductive potential than mesoscale variability. An erratum to this article can be found at     

Effect of metallic cations on the sorption of pesticides on soil

We studied the adsorption and desorption of two pesticides, namely isoproturon and dimetomorph, onto a model soil sample. We first show that the adsorption of isoproturon depends on pH, from 1 mg g⁻¹ at pH 4 to 2 mg g⁻¹ at pH 10, contrary to the adsorption of dimetomorph (5.8 mg g⁻¹). We also studied the influence of metallic cations, copper(II), iron(III), manganese(II), and chromium(III), on the sorption of isoproturon and dimetomorph. We found that in the case of isoproturon, the presence of metallic cations does influence the retention capacity of the soil sample. The sorption becomes very weak in the presence of copper and chromium, whereas in the case of iron and manganese the sorption properties are slightly modified.     

Population structure of an exploited benthic cnidarian: the case study of red coral (Corallium rubrum L.)

Octocorals are an important part of many ecosystems as they add three-dimensional complexity to the benthos and thereby increase biodiversity. The Mediterranean red coral (Corallium rubrum, L. 1758) is a longevous octocoral that is harvested commercially, yet natural and anthropogenic influences on its population size structure are little understood. This study found that some harvested red coral populations had a significantly different size structure when compared to populations at the nearby Marine Protected Area (MPA) of Medas Islands at the Spanish Costa Brava (NW Mediterranean). Eighty-nine percent of the red corals in the harvested Costa Brava area are less than 10 years old and 96% of all colonies have not yet grown more than second-order branches. The size/age distribution of the harvested population is notably skewed towards younger and smaller colonies. Thus, although red coral is still abundant, its population structure is strongly distorted by harvesting. The results confirm that MPAs are useful to distinguish between anthropogenic and natural influences on population structure. However, 14 years of protection appears to be an insufficient recovery time for a longevous octocoral population such as red coral.     

Physiological and antioxidative response of Brassica nigra (L.) to ZnO nanoparticles grown in culture media and soil

Abstract

To investigate metal nanoparticle-induced phytotoxicity, Brassica nigra seeds were exposed to 50–1000?mg L^?1 ZnO nanoparticles in culture media and 100–1000?mg kg^?1 in soil. Plant length and weight were adversely affected in culture conditions, but with soil the effect was not significant. Determination of the radical-scavenging potential revealed that soil grown plants were less stressed than plants grown on culture medium. The total antioxidant and reducing power potential of soil grown plants were less variable compared to plants grown on culture medium. Total phenolic and flavonoid concentrations varied in plants, which changed with the nanoparticle’s concentrations in medium and soil. High performance liquid chromatography analysis showed that rutin was the major antioxidative molecule that significantly increased in nanoparticles-stressed B. nigra plants.     

玉米幼苗根系形态对芘污染的响应

采用盆栽试验探讨了玉米（Zea mays L.）根系形态学参数（根质量长度、根质量面积、根质量体积、根平均直径及不同根直径等级分布）对不同浓度芘污染胁迫的响应。较低浓度芘可适当地刺激玉米的生长,高浓度芘处理抑制了玉米的生长,并且抑制作用随芘处理浓度的提高而增强;芘对玉米根系的影响要大于对茎叶的影响。不同浓度芘处理下玉米根系形态学参数发生了显著的变化,与对照相比,芘处理下根直径显著降低,根质量长度、根质量面积和根质量体积显著增大,且随芘处理浓度的提高其效应更显著。     

根表铁膜对水稻铅吸收转运的影响

通过温室土壤盆栽试验研究不同生育期水稻根表铁膜形成对水稻吸收和转运Pb的影响。结果表明,两种水稻根表铁膜形成量(以DCB-Fe含量计)及铁膜中吸附的Pb量均随着生育期的延长而减少。水稻根表铁膜Fe含量与铁膜吸附的Pb量呈显著的正相关关系(r=0.798,p0.01)。水稻根系和茎叶吸收积累Pb随着不同品种和不同生育期而变化。品种NK57籽粒Pb含量显著高于品种YD6,前者为后者的1.9倍。从富集系数和分配比率来看,Pb主要富集在水稻的铁膜和根系中,而积累在茎叶和籽粒中的比率较少。Pb从水稻根表铁膜、根系和茎叶向籽粒中的转运系数在两个水稻品种间差异均不显著。水稻分蘖期和孕穗期根表铁膜量与根系Pb含量均呈显著的正相关关系(p0.05),但是成熟期水稻根表铁膜量与根系、茎叶和籽粒中Pb含量相关性均不显著,说明根表铁膜形成对水稻分蘖期和孕穗期吸收积累Pb有一定影响,但对水稻成熟期根系、茎叶和籽粒吸收积累Pb影响不大。