环境放射性核素137Cs和210Pbex的田间原位测定研究

原位现场γ谱仪具有快速准确监测土壤中环境放射性核素137Cs和210Pbex的潜力,可以解决传统环境放射性核素示踪土壤侵蚀在选择参考点和测定时间过长问题。本研究应用现场γ谱仪(ISOCS,In-situObject Counting System),对内蒙古锡林浩特草原土壤中137Cs和210Pbex的含量进行了田间原位(不采样)测定,并与室内γ谱仪测定结果进行了比对。结果显示:现场γ谱仪的探头离地面1m,采用90度准直器,测量时间保证3600s以上时,测定的土壤中137Cs面积浓度与室内测定结果一致,二者的平均偏差为8%,表明现场γ谱仪测定具有较高精度,是快速评价土壤侵蚀速率的有效技术;210Pbex的原位测定结果显著高于室内测定结果,可能由于测定时间较短所致。初步研究结果表明:原位测定具有时间短、精度高的优点,可以克服传统采样造成的空间变异误差。     

Influence of temperature on copper accumulation and depuration in a tropical cerithiid Cerithidea (cerithideopsilla) cingulata (Geelin 1790)

The effect of temperature on Cu accumulation and depuration in the tissues of Cerithidea cingulata was studied at 18 °C, 28 °C, and 38 °C. The LC₅₀ value for 5 days was observed to be high at ambient temperature (28 °C) that at the high temperature (38 °C). The LC₅₀ for 10 days at the low temperature (18 °C) was higher than at the ambient (28 °C). When exposed to sublethal concentrations for 48 hr, the tissue accumulation of Cu was found to be more at the high temperature than at the ambient and low temperature. The depuration process was faster at high temperatures, and the animals returned to normal condition after 36 hr. At the ambient and low temperature, Cu accumulation was slow and prolonged, and the animals resumed to normal condition after 48 and 72 hr, respectively. The gonad-digestive gland (GDG) complex was found to show greater changes in accumulation and depuration process when compared to foot and viscera.     

两个棉铃虫酯酶基因(001f和001g)在杆状病毒表达载体系统(BEVS)中的表达及酶活分析

昆虫羧酸酯酶(carboxylesterases,CarEs)对有机磷、拟除虫菊酯、氨基甲酸酯等三大类化学杀虫剂的代谢解毒作用是昆虫代谢抗性产生的一种重要机制.为明确棉铃虫(Helicoverpa armigera)两个酯酶基因001f和001g在代谢抗性中的作用,本研究基于杆状病毒表达载体系统(BEVS)在草地夜蛾(Spodoptera frugiperda)Sf9细胞系中成功表达了酯酶基因001f和001g,表达产物经非变性聚丙烯酰胺凝胶电泳和α-乙酸萘酯染色,结果表明,两个酯酶的条带染色很深,染色条带主要分布在相对迁移率(Rm)值为0.27～0.36和0.37～0.48之间的两个区域.进一步采用酶标仪测定了表达产物对α-乙酸萘酯(α-naphthyl acetate)和4-硝基苯基乙酸酯(para-nitrophyl acetate)的酶促代谢动力学特性,结果表明,两个酯酶对底物均有极强的亲和力和非常高效的催化效率,其对α-乙酸萘酯的亲和系数(Km值)分别为(3.9±0.6)和(3.3±0.4) μmol/L,速率常数(kcat/Km值)高达(95±9.3)和(26.5±1.9) μmol-1·s-1·L；相比较而言对于4-硝基苯基乙酸酯的kcat/Km值较低(分别为(4.47±0.33)和(12.8±0.10) μmol-1 ·s-1·L).上述结果在生化水平上证实了两个酯酶均具有较强代谢作用,预示着这两个酯酶基因与棉铃虫的代谢抗性可能相关,并可能对有机磷、拟除虫菊酯等化学杀虫剂也具有一定代谢解毒作用.     

乙肝表面抗原基因表达载体的构建及对百脉根的转化

利用PCR成功的从乙肝患者血清中扩增出乙肝表面抗原基因,并构建了含有此基因的植物表达载体pBHB。用根癌农杆菌(Agrobacterium tumefaciens)介导叶盘法将乙肝表面抗原基因转入百脉根(Lotus corniculatus),从转化植株中提取DNA做PCR检测、Southern杂交,阳性结果验证了目的基因已整合到百脉根的基因组中,转化效率为20%,证实转化的载体真实高效。     

Phosphorus uptake and use efficiency in different varieties of bread wheat (Triticum Aestivum L)

Thirty spring wheat varieties were evaluated and classified into eight different groups on the basis of their grain yield performance and phosphorus (P) uptake using Metroglyph analysis. Significant variability was observed for grain and biomass yield, plant height, P content in grain and straw, total P uptake and phosphorus harvest index and P use efficiency traits. Varieties WH 711 and PBW 343 exhibited high grain yield as well as high P uptake (HGY-HP). WH 283 and UP 2425 with high index score of 19 and 16 respectively, constituted the high grain yield-medium P uptake (HGYMP) group. Both these varieties, though had similar grain yield of 5348 kg/ha, but WH 283 (12.64 kg/ha) utilized much lower P as compared to UP 2425 (16.94 kg/ha). Moreover, WH 283 (81.64) also showed higher values for phosphorus harvest index (PHI) than UP 2425 (67.88%). P uptake of WH 283 was comparable with that of Raj 3765 (10.78 kg/ha) and grouped into high grain yield and low P uptake (HGY-LP) group. The grain yield performance of these two varieties with a relatively low P uptake is reflected in their high index score for P use efficiency thus, earmarking them for low P regimes. Variety HW 2006, despite low grain yields of 4665 kg/ha had high index score of 16 due to its higher value for Phosphorus Biological (PBER) and Economic Yield (PEER) Efficiency Ratio as it has effected least (7.18 kg/ha) P mobilization. In addition high P translocation in the grain was also observed for this variety. Inter-mating of genotypes like HW 2006, UP 2338 and HW 2016 with those belonging to HGY-HP (PBW 343 and WH 711) and HGY-LP (Raj 3765 and WH 283) would be an ideal strategy to develop the cultivars for efficient phosphorus use.     

~(12)C~(6+)重离子辐照大葱的细胞学和RAPD分析

用309、0和180Gy12C6+重离子辐照处理大葱干种子,研究其对大葱根尖的细胞学效应,并采用随机扩增多态性DNA(RAPD)技术初步分析了其变异类型。不同剂量12C6+的重离子照射能有效诱导大葱根尖细胞微核和染色体畸变。随着辐照剂量的增加,幼苗根尖细胞微核形成几率明显增大,微核率、多微核率和染色体总畸变率呈线性上升。但除去微核以外的染色体畸变率则呈U型变化。RAPD结果表明,大葱不同处理之间的DNA存在明显差异,所用35种引物中有28种出现了特异性条带,既有新增条带,又有缺失条带,还有迁移率的差异。30、90和180Gy剂量辐照引起的RAPD变异率分别为29.91%、41.05%和22.14%。结果发现高微核率和染色体变异过大会导致高致死效应,使得染色体总畸变率高的处理组在当代生长苗的DNA变异率变小。     

Enzyme-linked immunosorbent assay (ELISA) and sol-gel-based immunoaffinity purification (IAP) of the pyrethroid bioallethrin in food and environmental samples

Enzyme-linked immunosorbent assay (ELISA) and sol-gel-based immunoaffinity purification (IAP) methods for the pyrethroid bioallethrin were developed and applied for monitoring bioallethrin in spiked food, soil, and dust samples. Attempts to determine bioallethrin content in fruit and vegetable extracts revealed high variability between sample preparations and marked interferences with the assay. Sol-gel IAP followed by solid-phase sample concentration was effective in removing the interfering components and resulted in high recovery of bioallethrin from spiked crude acetonic extracts of fruits and vegetables, even in the presence of high extract concentrations (28%). Solid-phase treatment alone failed to remove the interfering components from the spiked sample. Gas chromatography-mass spectrometry analysis of the IAP samples revealed bioallethrin as a doublet unsolved peak because of the cis and trans isomer present in the standard with confirmation of its mass. Unlike fruit and vegetable extracts, soil and dust samples did not interfere with the ELISA, and the bioallethrin content in those samples could be determined with high precision without the need of any further purification.     

地下水埋深和灌水频率对土壤溶质(Br-)运移的影响

通过室内均质土柱试验,以Br-为示踪剂,研究了90 mm/15 d和30 mm/5 d两种灌水频率下,1.7,1.2,0.8 m地下水埋深土壤中溶质(Br-)的运移规律。结果表明:不同地下水埋深或同一地下水埋深条件下,高、低灌水频率土壤中溶质运移快慢的趋势是变化的。地下水埋深由深变浅,高灌水频率土壤中溶质(Br-)运移由慢于低灌水频率逐渐转变为快于低灌水频率;高灌水频率土壤中Br-较集中地向下运移,低灌水频率土壤中地下水埋深越大,Br-分布越均匀分散;高灌水频率不利于土壤溶质(Br-)积聚于土表。     

Metabolism of 7-fluoro-6-(3,4,5,6-tetrahydrophthalimido)-4- (2-propynyl)-2H-1,4-benzoxazin-3(4H)-one (S-53482) in rat. 1. Identification of a sulfonic acid type conjugate

To examine the metabolic fate of 7-fluoro-6-(3,4,5, 6-tetrahydrophthalimido)-4-(2-propynyl)-2H-1,4-benzoxazin-3( 4H)-one (S-53482), rats were given a single oral dose of [phenyl-(14)C]-S-53482 at 1 (low) or 100 (high) mg/kg. The radiocarbon was almost completely eliminated within 7 days after administration in both groups. (14)C recoveries (expressed as percentages relative to the dosed (14)C) in feces and urine were 56-72 and 31-43%, respectively, for the low dose and 78-85 and 13-23%, respectively, for the high dose. S-53482 and seven metabolites were identified in urine and feces. Six of them were purified by several chromatographic techniques and identified by spectroanalyses (NMR and MS). Alcohol derivatives and an acetoanilide derivative were isolated from urine. Three sulfonic acid conjugates having a sulfonic acid group incorporated into the double bond of the 3,4,5,6-tetrahydrophthalimide moiety were isolated from feces. On the basis of the metabolites identified in this study, the metabolic pathways of S-53482 in rats are proposed.     

Effect of Fertilizer Nitrogen (N) on Soil Organic Carbon,Total N,and Soil pH in Long-Term Continuous Winter Wheat (Triticum Aestivum L.)

Carbon sequestration via sound agronomic practices can assist in combating global warming. Three long-term experiments (Experiment 502, Experiment 222, and The Magruder Plots) were used to evaluate the effect of fertilizer nitrogen (N) application on soil organic carbon (SOC), total nitrogen (TN), and pH in continuous winter wheat. Soil samples (0–15 cm) were obtained after harvest in 2014, analyzed, and compared to soil test results from these experiments in 1993. Soil pH decreased with increasing N fertilization, and more so at high rates. Nitrogen application significantly increased TN in Experiment 502 from 1993 to 2014, and TN tended to be high at high N rates. Fertilizer N significantly increased SOC, especially when N rates exceeded 90 kg ha^?1. The highest SOC (13.1 g kg^?1) occurred when 134 kg N ha^?1 was applied annually. Long-term N application at high rates increased TN and SOC in the surface soil.     

Lake Kinneret (Israel) Ecosystem: Long-term Instability or Resiliency?

The Kinneret ecosystem has undergone significant man-made modifications. These include, among others: construction of the south dam (1932); drying of Hula Lake and swamps (1950s); salty springs diversion (1964); lake water salinity decline from 395 (1961) to 210 ppm chlorid; deepening of the Jordan River near Bnot-Yaacov bridge (1971) with consequent high loads of suspended matter; National Water Carrier (NWC) operation (1964); sewage removal and fishpond restriction in the catchment; implementation of the Hula Project (1994–1998); introduction of native and exotic fishes; an amplitude of water level fluctuations of 4.8 m. Natural fluctuations occurred as well: heavy floods with high nutrient loads in 1968/69 and 1991/92 and droughts in 1973, 1989–1991 and 1998–1999; 4.6 m water level fluctuations; low temperatures (12.3°C) and fish kill in 1971/72 and 1991/92; no mixing period in 1984; low (1975, 1996–1997) and high biomass of Peridinium (1994, 1998); N₂-fixing cyanobacterium bloom (1994, 1995); high stock of Lavnun (Acanthobrama) fishes (1990s); zooplankton biomass decline (1969–1993) and increase afterwards. Although man made changes and natural environmental changes were significant, the lake ecosystem did not deviate from the level of resilient fluctuations and the classification of long-term instability in Lake Kinneret is probably an overestimation. In this paper I use long-term (31 years) distribution data of plankton, nutrients, and water level in Lake Kinneret to distinguish between resiliency and instability.     

Foliar symptoms,ethylene biosynthesis and water use of young Norway spruce (Picea abies (L.) Karst.) exposed to drought and ozone

Four-year old Norway spruce (Picea abies (L.) Karst.) trees were pretreated at low and high water supply, and then placed into a growth chamber containing four compartments so that two levels of ozone exposure, 0.02 and 0.4 Μl l^?1, could be replicated. They were exposed to ozone and drought stress for 59 days, and water use was determined by periodic weighing. Small effects of ozone treatment were detected on new shoot dry weight, and water use by trees receiving the high ozone treatment appeared higher. Both visual symptoms and ethylene biosynthesis showed that drought stress reduced damage to trees exposed to high ozone. Ethylene emission and 1-aminocyclopropane-1-carboxylic acid (ACC) levels increased after 18 days of exposure to 0.4 Μl l^?1 ozone, while visual symptoms were seen at 30 days. After 59 days of exposure to the combined stresses, ethylene and ACC levels were lower, but showed an ozone x water interaction. Most ethylene and ACC were produced by wet trees at high ozone concentration, but dry trees also had high ethylene and ACC levels at low ozone. Levels of needle malonyl-ACC (MACC) were not significantly affected by treatment, and did not change with time, but root MACC levels, which were twice needle levels, were high in wet trees at high ozone concentration, but also high in dry trees at low ozone concentration. These results suggest that drought stress occurring during ozone exposure could be expected to reduce damage to young Norway spruce, and that this damage may be related to ethylene biosynthesis.     

Growth and physiological characterization of low nitrogen responses in Tibetan wild barley (Hordeum spontaneum) and cultivated barley (Hordeum vulgare)

Development of crop cultivars with high yield under low nitrogen (N) supply is a basic approach for the enhancement of agricultural sustainability. The previous studies showed that Tibetan wild barley shows wider genetic diversity in abiotic stress and poor fertility tolerance. In this study, four barley genotypes (two Tibetan wild and two cultivated), differing in N use efficiency (NUE), were characterized for their growth and physiological responses to low N stress. The genotypes ZD9 (cultivated) and XZ149 (wild) with high NUE performed better in terms of shoot dry weight (DW) and photosynthetic parameters under both low and normal N levels and had higher antioxidative enzyme activities, N concentration, and accumulation in both shoots and roots under low N stress. The current results showed the substantial difference among barley genotypes in low N tolerance and verified the significance of Tibetan wild barley in the genetic improvement of cultivated barley in NUE.     

Carica candicans Gray (Mito), an alimentary resource from Peruvian flora.

In addition to some histological observations, the chemical composition of Carica candicans Gray (Caricaceae) fruit and seeds, a plant common in Peruvian nutritional habits, was determined. The fruit contains high amounts of total proteins (8.2% on dry weight basis) and carbohydrates (70.1%) and appreciable contents of vitamin C and minerals. The oil extracted from seeds is in high amount (41. 6%). The fatty acid composition, with a prevalence of oleic, palmitic, and linoleic acids, suggests a possible use of this oil in alimentation.     

Characterization of medium-chain triacylglycerol (MCT)-enriched seed oil from Cinnamomum camphora (Lauraceae) and its oxidative stability

Medium-chain triacylglycerol (MCT)-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO(2)) from Cinnamomum camphora seeds. The SFE-CO(2) process was optimized using the Box-Behnken design (BBD). The maximum oil yield (42.82%) was obtained under the optimal SFE-CO(2) conditions: extraction pressure, 21.16 MPa; extraction temperature, 45.67 °C; and extraction time, 2.38 h. Subsequently, the physicochemical characteristics, fatty acid composition, triacylglycerol (TAG) composition, tocopherol content, and DSC profile as well as oxidative stabilities of C. camphora seed oil (CCSO) were studied. Results showed that CCSO contained two major medium-chain fatty acids, capric acid (53.27%) and lauric acid (39.93%). The predominant TAG species in CCSO was LaCC/CLaC (ECN 32, 79.29%). Meanwhile, it can be found that CCSO had much higher oxidative stabilities than coconut oil due to the higher content of tocopherols in CCSO (α-tocopherol, 8.67 ± 0.51 mg/100 g; γ-tocopherol, 22.6 ± 1.02 mg/100 g; δ-tocopherol, 8.38 ± 0.47 mg/100 g). Conclusively, CCSO with such a high level of MCTs and high oxidative stabilities could be potentially applied in special food for specific persons such as weak patients and overweight persons because oils enriched in MCTs can be rapidly absorbed into body to provide energy without fat accumulation.     

Phytoextraction of Cadmium and Phytostabilisation with Mugwort (Artemisia vulgaris)

Artemisia vulgaris (mugwort) is a tall (1.0?C2.0 m) high biomass perennial herb which accumulates considerable amounts of metals on contaminated sites. An outdoor pot experiment was conducted on a sandy, slightly alkaline soil of moderate fertility to study the uptake of cadmium and the distribution of Cd in plant tissues of A. vulgaris. Cadmium was applied as CdCl₂ (a total of 1 l solution of 0, 10, 50 and 100 mg Cd l^?1) to 12-l pots with a height of 25 cm. HNO₃- and water-extractable concentrations of Cd were correlated with the applied Cd at 2-cm soil depth, but were not correlated at 20-cm soil depth, suggesting that Cd was either not mobile in the soil or completely taken up by mugwort roots. The Cd concentrations in different organs of A. vulgaris and litter increased with increasing soil contamination. Leaf/soil concentration ratios (BCFs) up to 65.93?±?32.26 were observed. Translocation of Cd to the aboveground organs was very high. The leaf/root Cd concentration ratio (translocation factor) ranged from 2.07?±?0.56 to 2.37 ± 1.31; however, there was no correlation of translocation factors to Cd enrichment, indicating similar translocation upon different soil contamination levels. In summary, A. vulgaris is tolerant to the metal concentrations accumulated, has a high metal accumulating biomass and accumulates Cd up to about 70% in the aboveground parts. Both a high phytoextraction potential and a high value for phytostabilisation would recommend mugwort for phytoremediation.     

Effect of phosphate and sulfate fertilizers on selenium uptake by wheat (Triticum aestivum)

The objective of this study was to investigate whether oxyanionic phosphate (P) and sulfate (S) fertilizer management could influence selenium (Se) uptake by wheat (Triticum aestivum) in medium and high Se areas. Field studies were established at two locations for two growing seasons in central South Dakota, USA. Phosphate fertilizer was applied using three different methods (banded with seed, surface-broadcasted in the fall, or surface-broadcasted in the spring) using six different P rates. Sulfate fertilizers were broadcasted at four rates in the fall. Selenium concentration in wheat grain was significantly influenced by the interaction of P application methods and rates, but it was dependent on location. Grain Se concentration decreased in high Se availability soil when P fertilizer was applied, due to the dilution effect. Grain Se concentration and uptake was significantly decreased as S applications increased due to the competition effect, but the depression was apparent in high Se availability soil. The results from this study showed that P and S fertilizer management can influence Se level in wheat grain grown in naturally high Se areas, even though overall grain Se level was strongly associated with location variation.     

Mold occurrence and aflatoxin B(1) and fumonisin B(1) determination in corn samples in Venezuela

Fumonisins are mycotoxins produced mainly by Fusarium moniliforme and Fusarium proliferatum, which have been associated with several animal and human diseases. Aflatoxins are hepatotoxic, mutagenic, and teratogenic metabolites produced by Aspergillus flavus and Aspergillus parasiticus. Both have been reported at high levels in corn. This study was pursued to determine mold, aflatoxin B(1) (AFTB(1)), and fumonisin B(1) (FB(1)) levels in white and yellow corn. Mold levels were determined using potato dextrose agar and identification of the main genus of molds present in corn, AFTB(1) levels by immunoaffinity chromatography, and FB(1) levels by a Bond-Elut SAX cartridge and HPLC. AFTB(1) an     

Limitations for revegetation in lead/zinc minesoils (NW Spain)

Purpose

Metal mining is the main cause of soil contamination caused by heavy metals. Mine tailings and minespoils generally offer hostile environments for plant growth due to their low nutrient availability, low organic matter content, and high trace metal content. This study was carried out with the aim of characterizing the soils that have developed on the tailings from an abandoned lead and zinc mine in Galicia (NW Spain) and determining the soil factors that limit revegetation.

Materials and methods

We selected three zones: (a) the minespoils, (b) in the mining area, and (c) the settling pond, where the sludge from the flotation process was deposited. A control soil was also sampled outside of the mining area. We analyzed the physicochemical properties and metal levels in the mine spoil and soil samples we collected.

Results and discussion

The results indicate that the main physical limitations of minesoils are their low effective depth, high porosity and stoniness, while the main chemical limitations are low organic matter content and low CEC and an imbalance between exchangeable cations. These minesoils are strongly affected by high Zn and Pb levels which hinder revegetation.

Conclusions

As high concentrations of toxic trace elements and a high pH are important factors in limiting the plant growth, the restoration procedure must overcome the oxidation processes by adding organic amendments that also contribute towards fixing heavy metals or by implanting spontaneous vegetation adapted to the mine conditions, such as common broom (Cytisus scoparius) or white birch (Betula celtiberica).     

Patterns of diversity in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millsp.) germplasm collected from different elevations in Kenya

Pigeonpea germplasm accessions collected from low (<500 m), medium (501–1000 m), high (1001–1500 m) and very high elevation zones (>1500 m) of Kenya were evaluated for 15 agronomic traits and seed protein content at ICRISAT, Patancheru, India. There were significant differences (P < 0.001) among elevation zones for the number of primary and secondary branches, days to 75% maturity, pod length, seeds per pod, 100-seed weight and seed yield. Mean values indicated that the accessions from low elevation zone were significantly different from those collected in higher elevation zones for early flowering and maturity, number of primary branches, pod length, number of pods per plant, seeds per pod, 100-seed weight, seed yield and harvest index. None of the accessions collected in Kenya belonged to extra early (<80 days to 50% flowering) and early (80–100 days to 50% flowering) maturity groups, as defined by time to flowering at Patancheru, India. Mean diversity index based on all characters indicated that accessions from the low elevation zone are more diverse than those from the higher elevation zones. Frequency distribution for trait extremes indicated that the accessions from the low elevation zone were early to flower and mature, short statured, produced more primary and secondary branches with high pod bearing length, long pods, more pods per plant, more seeds per pod, a high seed yield and harvest index. Accessions from the very high elevation zone were late flowering, with a large number of tertiary branches, large seeds and a high shelling percentage and could be a source for cold tolerance and the breeding of vegetable types. Results suggest that the elevation of collection sites is therefore a very important determinant of variation patterns of pigeonpea in Kenya.