铜尾矿对油菜生长和生理功能的影响

通过盆栽试验,研究了铜陵铜尾矿对油菜生长和生理功能的影响.结果表明,油菜种子能在铜尾矿上萌发,但发芽率和发芽速率均小于正常土壤.尾矿能降低油菜叶绿素含量,而且对叶绿素a/b比值也有影响.在尾矿胁迫下,油菜叶片的细胞膜透性增加,硝酸还原酶活性降低,抗坏血酸含量下降,表明尾矿对油菜具有毒害作用.与对照相比,尾矿处理油菜根系表现为主根变短,侧根数减少,根系体积明显变小.尾矿能明显抑制油菜幼苗的根和茎叶生物量,降低根冠比.随着油菜的生长发育,尾矿的毒害作用更加明显.尾矿对油菜的影响最终反映在油菜的产量上.铜元素的毒害和尾矿的极端贫瘠是影响油菜生长的2个因素.成熟期油菜各器官铜含量大小依次为根＞茎叶＞籽粒,籽粒中铜含量与土壤和尾矿混合物中有效铜含量在α=0.01水平上显著正相关.     

镉胁迫对小白菜（Brassica campestris L.）抗氧化机理的影响

采用水培的方法,研究了不同Cd2 水平(0、1、2.5、5、10、15mg·L-1)对小白菜(Brassica campestris L.)抗氧化酶(SOD、POD、CAT)活性、非酶物质(SH、GSH、PCs)含晕以及生长的影响.结果表明,小白菜叶片和根系SOD活性随Cd处理质量浓度的增加呈降低的变化趋势,POD、CAT活性以及MDA含量随Cd处理质量浓度的增加而增加.小白菜的生物量、根长、株高、叶绿素质量分数随Cd处理质量浓度的增加显著降低(P<0.05),表明Cd抑制了小白菜的生长,破坏了叶绿素的合成.小白菜地上、地下部镉质量分数均随Cd处理质量浓度的增加而显著增加(P<0.05).当Cd处理质量浓度为15 mg·L-1,小白菜地上、地下部镉质量分数分别达到637.5、1 663.0 mg·kg-1,表明小白菜对Cd有良好的富集效果.小白菜根系与叶片中SH、GSH和PCs含量均随Cd处理质量浓度增加而增加的变化趋势,表明SH、GSH和PCs在解毒小白菜Cd毒害中起着重要作用.     

不同收获时期和控氮条件对水培小白菜硝酸盐含量的影响

在水培中采用收获前降低营养液浓度、完全停止供氮以及在不同时期采收等方法来研究小白菜硝酸盐含量的控制方式及其效果,结果表明:适时采收和收获前适当控氮可以降低小白菜的硝酸盐含量。在小白菜生长第26d左右硝酸盐含量最低,此后l~2d产量增长较快,此时采收品质较好;小白菜硝酸盐含量呈明显的日变化,并且与硝酸还原酶活性呈正相关,在下午16:00时左右采收硝酸盐含量最低,仅为894mg.kg-1;完全断氮7d后,小白菜硝酸盐含量显著降低,但产量也受到明显的影响。而采用低浓度营养液控氮4d左右采收既可控制硝酸盐含量又不会使产量过低。     

The timing of premating and mating behavior in a field population of the cricket Gryllus campestris L.

Summary In a field population of Gryllus campestris, 209 males and 175 females were marked individually and their migratory and mating behavior was observed. Many females and males mate more than once and both sexes change burrows frequently. All copulations observed were during the day. Automatic recording of calling in 12 selected males, and walking in 7 females, showed that an individual male may call predominantly during the day, during the night, or both day and night, but the females show locomotory activity predominantly during the day. Thus, female locomotion is significantly temporally correlated with copulation but not with male calling.     

Retention characteristics of Cu2+, Pb2+, and Zn2+ from aqueous solutions by two types of low lime fly ashes

The technical feasibility of utilization of fly ash as a low-cost adsorbent for the removal of metals from water has been studied. For two types of fly ashes, the retention capacities of copper, lead, and zinc metal ions have been studied. Contact time, initial concentration, and pH have been varied and their effect on retention mechanism has been studied. The dominant mechanisms responsible for retention are found to be precipitation due to the presence of calcium hydroxide, and adsorption due to the presence of silica and alumina oxide surfaces in the fly ash. First-order kinetic plots have revealed that the rate constant increases with increase in the initial concentration and pH. Langmuir adsorption isotherms have been plotted to study the maximum adsorption capacities for metal ions considered under different conditions. X-ray diffraction studies revealed the formation of new peaks corresponding to respective metal ions precipitates under alkaline conditions.     

Hydrobiological study of Dahikhuta reservoir

Physico-chemical parameters and the algae of Dahikhuta reservoir, near Malegaon, Dist. Nasik (Maharashtra) have been investigated during July to December 1998. The results have revealed that reservoir water is classified as oligotrophic on the basis of water quality criteria. This paper also reports algal diversity. Total 19 algal taxa are reported from three classes.     

Efficacy of fenvalerate as contact poison against the larval development and viability of mutant form (Sepia) of Drosophila melanogaster (Meigen)

Fenvalerate, a synthetic pyrethroid, was analysed for its toxic effects on Drosophila melanogaster. It has been estimated that LC50 0.0166 micro 1/100 ml food is threshold of lethality. These studies have also revealed that fenvalerate is toxic as it had a pronounced effect on the rate of development and viability.     

Monofunctionalized cyclodextrin polymers for the removal of organic pollutants from water

Water is an important resource for domestic, industrial, agricultural and recreational purposes. The quality of water is however significantly deteriorating due to the accumulation of organic pollutants in aqueous systems. Conventional water treatment technologies fail to remove these contaminants to desirable levels. Recent studies have revealed that cyclodextrin nanoporous polymers are capable of absorbing pollutants from water to parts per billion levels. We have demonstrated that functionalised cyclodextrin polymers have enhanced absorption capacities for some organic pollutants. Here we report the synthesis of several insoluble monosubstituted cyclodextrin polymers or “nanosponges”. We show that these polymers have improved abilities in the absorption of p-nitrophenol and pentachlorophenol from aqueous solutions.     

Sperm chemotaxis in the hydromedusae. II. Some chemical properties of the sperm attractants

Gel filtration on highly cross-linked molecular sieves of the sperm attractants of some hydromedusae revealed that the active agents differ in their molecular weights. These differences fall roughly along taxonomic lines, at least at the order level. Anthomedusae have attractants with molecular weights greater than 5,000, while the Leptomedusae attractants have weights less than 1,000. The Limnomedusae and Trachymedusae attractants have weights above 5,000. All the attractants are heat-stable, but only those of the Leptomedusae can pass across a dialysis membrane with a molecular weight cut-off of 14,000.     

Heavy metal accumulation in certain marine animals along the East Coast of Chennai, Tamil Nadu, India

Heavy metals disposed through anthropogenic activities find their way into the oceans and seas through the rivers or through direct fall out from factory effluents. These heavy metals resuspend back into the water column along with the sediments and are known to affect the marine animals. Marine animals like fish, prawn, crab and mussel were collected along the East Coast (off Pulicat lake to Chennai Harbour) to evaluate trace metal concentrations in various tissues. The above specimens accumulated heavy metals such as Zn, Pb, Cu, Co, Cr, Ni and Cd. Fish, prawn, crab and mussel revealed higher concentration of heavy metals such as Zn, Pb, Cr Co, Cu and Ni and Cd in low levels. The results revealed that the heavy metal concentrations in the marine animals are below the threshold levels associated with the toxicological effects and the regulatory limits. The bioconcentration factors revealed that the animals have accumulated heavy metals along the food chain rather than from the water column and sediment.     

施肥对大白菜吸收电镀污染土壤中重金属的影响

采用田间试验,研究了在不同施肥条件下重金属在土壤-作物系统中迁移、积累的特性.结果表明,不同施肥处理对降低植物重金属吸收的影响能力大小依次为有机肥＞复合肥＞尿素,一般地,作物不同部位对Cr、Cu 积累量的大小顺序为根＞叶＞茎,重金属在土壤-作物系统中迁移能力大小依次为Cu＞ Ni＞Cr,3种施肥处理对降低土壤中有效态重金属含量的影响能力大小依次为有机肥＞复合肥＞尿素.     

中药免疫增强剂抗肿瘤作用机理及物质基础

近年来,中药免疫增强剂的作用机理及物质基础逐渐被现代医学不断研究揭示.研究表明中药中的多糖类,苷类,黄酮类,挥发油类等成分能提高机体的免疫能力,能够明显增强免疫器官的重量,增强体液免疫和细胞免疫及促进机体产生细胞因子等作用.参31.     

Food of Anguilla anguilla in Lake Manzalah,Egypt

The food and feeding habits of Anguilla anguilla L. in Lake Manzalah (Egypt) have been studied. Analysis of stomach contents revealed that eels alter their type of diet as they grow. Their feeding rate varies also with season, size and environmental temperature. A negative correlation was found between length and feeding index of A. anguilla.     

中国农产品产地环境标准中存在的问题与对策研究

目前中国已经颁布的各类产地环境类标准已超过30多个(不含地方标准)，与欧美发达国家同类标准相比，中国现行的产地环境类标准普遍存在着制定程序不严谨、相关标准之间衔接统一不够、标准的科学技术水平不高、标准的针对性与实用性不强、标准与分析检验方法不配套等共同的问题。通过实例和数据，对以上问题进行了研究和分析，提出了改革现行的标准管理模式、加强基础性科学研究、借鉴和引进国际先进标准、培育专业技术队伍等对策措施。     

The effects of shark cage-diving operations on the behaviour and movements of white sharks, Carcharodon carcharias, at the Neptune Islands, South Australia

The attraction or provisioning of sharks for the purpose of tourism is a lucrative and popular industry that remains controversial regarding its possible risks to target species and impacts on local ecosystems. The long-term impacts of such activities on the behaviour and movement patterns of sharks have typically been difficult to establish as most studies investigate contemporary behaviour concurrent with existing operations and thus have no comparative base from which to compare effects. We compared patterns of residency and behaviour of acoustic-tagged white sharks at the Neptune Islands in South Australia between periods before and after an abrupt and sustained doubling of cage-diving effort that occurred in 2007. The number of sharks reported by cage-dive operators significantly increased after 2007. Comparisons also revealed there were significant increases in sharks’ periods of residency, the periods spent within areas where shark cage-diving operations occur and changes in sharks’ diel pattern of habitat use. Changes were site-specific with no significant differences in shark behaviour revealed over the same period at an island group 12 km from regular shark cage-dive sites. The results suggest that cage-diving operations can lead to long-term changes in the site-specific behaviour of a highly vagile shark species which may need to be considered in the context of their conservation and in managing the impacts of the industry.     

Origin of Antarctic Isopoda (Crustacea,Malacostraca)

An analysis of the horizontal and the vertical zonation of the Antarctic Isopoda, combined with knowledge of the geological history of Antarctica and isopod phylogeny, revealed that the isopod family Serolidae and subfamily Arcturinae are likely to have evolved from ancestors that inhabited a cold-temperate Gondwanian province. Antarctic species of other families, such as the Munnopsidae, Nannoniscidae, Desmosomatidae and Ischnomesidae, are likely to have evolved from deep-sea ancestors. It is deduced that emigration of South Patagonian species into the Southern Ocean, although possible, probably did not occur very often. Evolutionary phenomena such as continental-drift vicariance, radiation of species on the continental shelf of Antarctica, and active migration, including submergence and emergence mechanisms are discussed.     

Elemental and biochemical composition of salps (Tunicata: Thaliacea)

Carbon and nitrogen content have been measured in the solitary and aggregate generations of 11 species of salps. Regression equations for each species and generation permit estimation of carbon or nitrogen content as a function of length of live individuals. Different species of the same length may have nearly tenfold differences in carbon content. Fractionation and biochemical analysis of some samples revealed that the organic content of salps is approximately 80% protein. Ash-free dry weights average 27% of dry weights; mean carbon content is 29% of ash-free dry weight. Excess ash-free dry weight not accountable as organic material is thought to be water of hydration.     

Displaced honey bees perform optimal scale-free search flights

Honey bees (Apis mellifera) are regularly faced with the task of navigating back to their hives from remote food sources. They have evolved several methods to do this, including compass-directed "vector" flights and the use of landmarks. If these hive-centered mechanisms are disrupted, bees revert to searching for the hive, but the nature and efficiency of their searching strategy have hitherto been unknown. We used harmonic radar to record the flight paths of honey bees that were searching for their hives. Our subsequent analysis of these paths revealed that they can be represented by a series of straight line segments that have a scale-free, Lévy distribution with an inverse-square-law tail. We show that these results, combined with the "no preferred direction" characteristic of the segments, demonstrate that the bees were flying an optimal search pattern. Lévy movements have already been identified in a number of other animals. Our results are the best reported example where the movements are mostly attributable to the adoption of an optimal, scale-free searching strategy.     

Habitat use by loggerhead sea turtles <Emphasis Type="Italic">Caretta caretta</Emphasis> off the coast of eastern Spain results in a high vulnerability to neritic fishing gear

Previous studies of loggerhead sea turtles have concluded that drifting longlines were the main threat for immature specimens in the western Mediterranean, because immature loggerhead sea turtles mainly inhabit oceanic waters. However, recent aerial surveys have revealed large numbers of immature loggerhead sea turtles over the continental shelf of eastern mainland Spain, where turtles are exposed to neritic fishing gears but not to drifting longlines. We satellite-tracked seven loggerhead sea turtles (minimum straight carapace length (SCLmin) range: 36.5–55.0 cm) to assess whether the turtles in this region are vagrants from the adjoining oceanic regions or whether these loggerheads mostly inhabit the continental shelf. Satellite-tracking revealed that six of the tagged turtles avoided the oceanic realm and made extended use of the continental shelf, whereas only one individual could be considered a true vagrant as it avoided the continental shelf and primarily used the oceanic habitat. These results are in sharp contrast with those previously reported for immature loggerhead sea turtles of similar size from the south-western Mediterranean and fit well a relaxed ontogenic model that was recently proposed for loggerhead sea turtles in the central Mediterranean. Furthermore, these results demonstrate the vulnerability of loggerhead sea turtles of eastern mainland Spain to neritic fishing gears, as three of the seven turtles died and one was bycaught incidentally while being tracked over the continental shelf.     

The two reindeer parasites,Hypoderma tarandi andCephenemyia trompe (Oestridae), have evolved similar olfactory receptor abilities to volatiles from their common host

Summary Using the linked gas chromatographical/electroantennogram (GC/EAG) technique it was revealed that the reindeer warble fly (H. tarandi) was specifically able to sense the same components from reindeer interdigital pheromone gland as the reindeer nose bot fly (C. trompe) another reindeer endoparasite. These two species belong to the same family (Oestridae), but different subfamilies, and the evolution towards an endoparasitic life cycle is thought to have been independent. The development of olfactory abilities to find reindeer from long distances is hypothesized to have taken place through convergent evolution or exists because of their common ancestry.