EDU对臭氧胁迫下菠菜急性伤害症状和光合特性的影响

如何减轻近地层臭氧(O3)体积分数持续升高对作物的影响是污染生态学研究的热点之一。运用改进的开顶式气室(open-top chambers,OTCs)装置,对嘉兴尖叶、嘉兴圆叶和荷兰35三种菠菜(Spinacia oleracea L.)进行连续5 d,每天8 h的臭氧急性暴露处理,且在暴露前24 h喷施300 mg.L-1质量浓度抗氧化剂ethylenediurea(EDU),研究EDU对臭氧胁迫下菠菜急性伤害症状及光合特性的影响。结果表明:(1)菠菜暴露于高体积分数O3时,叶片出现失水干枯、坏死斑等急性伤害症状,光合色素含量、气体交换参数和光响应参数显著降低,且下降幅度和暴露体积分数呈正相关。(2)菠菜经EDU处理后,光合特性参数明显提高。对O3和EDU作双因子分析发现,随着臭氧体积分数升高,EDU对叶片气体交换参数的影响显著,而对其他参数的影响不明显。由此可见,尽管EDU的防护作用对高体积分数的O3胁迫是有限的,但喷施EDU仍能有效减轻O3对植物的伤害,这对缓解农田生态系统O3污染灾害有积极意义。     

砷-硒交互作用对水稻吸收转运砷和硒的影响

采用溶液培养法,研究了两种形态无机As与四价Se交互作用对水稻吸收转运As和Se的影响.结果表明,不同形态As与Se交互作用对水稻吸收转运As和Se影响较大,Se(Ⅳ)显著地提高水稻根系而降低水稻茎叶对As的吸收积累.与对照处理相比,在1.0μmol·L-1As(Ⅲ)和As(Ⅴ)处理下添加1.0μmol·L-1Se(Ⅳ)分别导致水稻根系As含量提高59.5%和21.3%,而水稻茎叶As浓度减少10.4%和21.9%.As(Ⅲ)或As(Ⅴ)处理显著降低水稻茎叶对Se的吸收积累,但As(Ⅴ)处理对水稻根系积累Se没有影响.在1.0μmol·L-1Se(Ⅳ)处理下,添加1.0μmol·L-1As(Ⅲ)和1.0μmol·L-1As(Ⅴ)导致水稻茎叶Se浓度分别比对照处理降低41.9%和30.3%.Se(Ⅳ)与As(Ⅲ)或As(Ⅴ)对水稻转运As、Se的能力具有交互拮抗作用.研究结果表明,在As污染农田中,可通过施用Se肥来提高植物的Se营养,降低植物对As的吸收积累,从而降低As对人体健康的危害.     

Behaviour of endosulfan in cabbage (Brassica oleracea L.)

Residue levels of endosulfan were determined in cabbage heads after being sprayed with a formulation containing the insecticide and upon storage at room temperature (15–27°C) and in a refrigerator (2–5°C). The half-life was calculated to be 4.8 and 5.5 days. Peeling removed the residues by 92%. Similarly, washing and washing followed by cooking removed 72% and 97% residue in cabbage stored at room temperature. These treatments were slightly less effective for samples stored in a refrigerator. Household processes such as peeling, washing, and washing followed by cooking should be regular practice before the vegetables are used.     

土壤残留氯磺隆和镉联合胁迫对菠菜代谢产物的影响

通过盆栽试验,评价土壤长残效期除草剂氯磺隆与重金属镉单一污染及复合污染对后茬作物菠菜生长、代谢产物的影响。基于GC-MS技术对3个不同处理组菠菜的代谢产物进行了辨识和分析。主成分分析结果表明,3个处理组的代谢物含量存在显著差异。具体表现为:1)与空白对照相比,氯磺隆诱导菠菜多种氨基酸、与能量代谢相关的3种糖类物质、苹果酸、γ-氨基丁酸、乳酸和腐胺的含量显著上升(*P0.05);肌醇显著下降(*P0.05);镉诱导菠菜多种氨基酸、与能量代谢相关的5种糖类物质、参与三羧酸循环的苹果酸和柠檬酸含量显著上升(*P0.05);肌醇和腐胺含量显著下降(*P0.05)。2)与单一污染相比较,复合污染诱导菠菜多种氨基酸,多种糖类物质和苹果酸等含量显著下降(*P0.05)。由此可见,复合污染减弱了氯磺隆和镉单一污染时对氨基酸代谢和能量代谢的上调作用;氯磺隆和镉之间没有协同作用,相反对某些特定的代谢物存在拮抗作用。     

大田条件下不同钝化剂对空心菜吸收镉的影响及机理

通过大田试验,研究4种钝化剂（赤泥、海泡石、钙镁磷肥和磷矿粉）对两茬空心菜（Ipomoea aquatica Forsk.）生长和镉吸收的影响。钝化剂施用量为：赤泥（0.5%和1.0%）、海泡石（0.3%和0.5%）、磷矿粉（450和900 kg.hm-2）、钙镁磷肥（450和900 kg.hm-2）。结果表明,各钝化剂均能显著降低土壤有效态镉质量分数,钝化能力大小表现为海泡石〉赤泥〉钙镁磷肥〉磷矿粉;钝化剂提高了空心菜地上部生物量,第1茬时（50 d）,施用高量赤泥、低量海泡石和高量钙镁磷肥处理生物量增加最为明显,地上部分别增加78.7%、75.2%和76.6%。第2茬（80 d）,高量赤泥与高量磷矿粉处理增加最高,地上部分别增加24.6%和34.5%。钝化剂对空心菜镉吸收影响不同,第1茬时对根系和地上部分别起促进和抑制作用,施用高量赤泥和高量海泡石最能抑制地上部镉累积,镉质量分数分别降低27.3%和23.2%。第2茬时,除海泡石外,钝化剂均显著抑制了根系和地上部的镉吸收,高量磷矿粉和赤泥效果最佳。总体来看,赤泥是保障农产品安全的最佳钝化材料,海泡石效果最差。     

Responses to sugars and their behavioural mechanisms in the starling (Sturnus vulgaris L.)

Summary The response of the starling to sugar solutions was investigated as this species, which eats sweet fruits, does not prefer sugar solutions according to the literature.In choice tests using two identical fountains, moderate preference for higher concentrations (0.5 M and 1 M) of glucose and fructose to water was demonstrated. The same concentrations of sucrose were rejected. Lower concentrations (0.25 M and less) of all three sugars were neither preferred nor rejected. In choice tests using two differently coloured fountains the subjects did not generally respond more sensitively to sugar solutions. In learning experiments with differently coloured fountains the starlings developed very marked preferences for 0.5 M glucose and 0.5 M fructose and a corresponding rejection of 0.5 M sucrose in the course of 1–2 days. In a learning experiment with dentical fountains they also developed a pronounced preference; the preference values obtained, however, are higher if secondary cues such as the colour of the fountain or its position are available. In short time tests immediate responses to sugar solutions could not be demonstrated.The rejection of sucrose is attributed to illness-induced aversion learning, the learned preference for glucose and fructose to the preference according to gain in energy per unit of time as postulated by the optimal foraging theory. Taste sensations play, if any, only a minor role. The learning mechanisms operating in the experiments could be employed by the starling for the selection of fruits.     

Females influence sperm storage and use in the yellow dung fly Scathophaga stercoraria (L.)

Summary The influence of the female on the process of sperm storage and use was examined. Copula duration, the condition of the female and whether or not a copula terminated naturally influenced the number of spermathecae (of three) in which once-mated females stored sperm. Females stored more sperm the larger their mate and the sperm from larger males were stored more unevenly amongst the spermathecae than were those from smaller males. Double-mated females had sperm in fewer spermathecae the larger the second of their mates and these spermathecae tended to be the ones which lay together within the female. The P2 values over three successive clutches were constant and sperm precedence was complete when the larger male was second to mate but began low and increased over subsequent clutches when the smaller male mated second. These results suggest females prefer, and are able, to use the sperm of larger males to fertilise their eggs. It is proposed that multiple spermathecae in Diptera have evolved to give females better control over offspring paternity.     

低磷胁迫下木豆利用磷的基因型差异及其机制

以木豆[Cajanus Cajan(L.)Millsp]MD2、MD5、MD7为材料,采用水培试验方法研究了木豆对磷的吸收、利用的基因型差异及其机理。结果表明:低磷(P1 μmol·L-1)胁迫下,木豆对磷素的吸收和利用效率存在明显的基因型差异,其中MD2、MD7属于磷素吸收、利用效率较强的基因型,而MD5为磷素效率较低的基因型。低磷培养16d后,磷高效的基因型的根/冠比显著增加,根分泌的酸性磷酸酶(APA)活性较高,说明木豆对磷素的吸收效率与植株的根冠比及根分泌的酸性磷酸酶活性有关。在低磷胁迫下,虽然MD7、MD2的含磷量较低,但是磷素利用效率和根尖中APA活性较高,说明根中高APA活性是磷利用效率高的重要原因之一。     

Influence of iron plaque on chromium accumulation and translocation in three rice (Oryza sativa L.) cultivars grown in solution culture

Hydroponic experiments were conducted to investigate the role of iron plaque on root surface in chromium accumulation and translocation in three rice cultivars (90-68-2, CDR22 and Jin 23A). Rice seedlings were grown under 1.0 mg L^?1 trivalent chromium (Cr(III)) stress with and without phosphorus (P) treatments. P addition significantly increased the shoot and root biomass in all three rice cultivars. In the absence of P, the amounts of iron plaque (DCB-extractable Fe) on the root surface increased resulting in the increase of Cr accumulation in iron plaque. Compared to that with P treatment, Cr concentrations in iron plaque without P treatment were enhanced by 2–3 folds in the three rice cultivars. There was a significantly positive correlation between DCB-extractable Cr and DCB-extractable Fe on the root surface of the three rice cultivars. There were no significant effects on Cr concentration in roots and shoots between P treatments, but significant differences among cultivars were observed. Cultivar Jin 23A had the lowest Cr concentration both in roots and shoots regardless of P treatment. The results suggest that iron plaque could be a trap for immobilising Cr from environment but may not affect Cr uptake and translocation. Screening and breeding the cultivars with low Cr accumulation is considered as the most effective approach in Cr contaminated areas.     

Larvicidal activity of neem and karanja oil cakes against mosquito vectors, Culex quinquefasciatus (say), Aedes aegypti (L.) and Anopheles stephensi (L.)

Larvicidal effect of neem (Azadirachta indica) and karanja (Pongamia glabra) oil cakes (individuals and combination) was studied against mosquito species. Both the oil cakes showed larvicidal activity against the mosquito species tested. The combination of neem and karanja oil cakes in equal proportion proved to have better effect than the individual treatments. The combination of the two oil cakes recorded an LC95 of 0.93, 0.54 and 0.77% against the mosquitoes, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi respectively The increase in efficacy of the combination treatment over individuals in all the mosquito larvae tested was found to range about 4 to 10 fold in terms of LC50 and 2 to 6 fold in terms of LC95.     

Effects of phosphorus on uptake and translocation of methylmercury in rice

The aim of this study was to determine uptake and translocation of MeHg in the absence or presence of P in three rice cultivars, named Tianyou196 (TY196), NanJing35 (NJ35), and ZiXiangnuo (ZX). Rice seedlings from each cultivar were divided into two groups. One group was grown in normal P (+P) nutrient solution and the other in absence of P or starvation (?P) nutrient solution for 2 weeks. Both groups were subsequently exposed to 200 mg/L MeHg chloride culture solution and maintained in a greenhouse for 4 weeks. The results showed that the amount of reddish Fe plaque outside rice root was significantly increased by P starvation treatment, but in the +P treatments, rice roots remained white. It is proposed that Fe plaque formed sequestered MeHg and consequently reduced translocation of MeHg from roots to shoots. It is of interest that MeHg content in roots and shoots of TY196 and NJ35 was 11.1%–18.8% and 28.9%–32.3% lower than in ZX, respectively. Therefore, in practice, depletion of P to enhance Fe plaque formation in rice growing area is effective in preventing MeHg translocation from roots to shoots and ensures food safety in mine locations.     

Effects of seawater pCO2 and temperature on shell growth, shell stability, condition and cellular stress of Western Baltic Sea Mytilus edulis (L.) and Arctica islandica (L.)

Acidification of the World’s oceans may directly impact reproduction, performance and shell formation of marine calcifying organisms. In addition, since shell production is costly and stress in general draws on an organism’s energy budget, shell growth and stability of bivalves should indirectly be affected by environmental stress. The aim of this study was to investigate whether a combination of warming and acidification leads to increased physiological stress (lipofuscin accumulation and mortality) and affects the performance [shell growth, shell breaking force, condition index (C_i)] of young Mytilus edulis and Arctica islandica from the Baltic Sea. We cultured the bivalves in a fully-crossed 2-factorial experimental setup (seawater (sw) pCO₂ levels “low”, “medium” and “high” for both species, temperature levels 7.5, 10, 16, 20 and 25 °C for M. edulis and 7.5, 10 and 16 °C for A. islandica) for 13 weeks in summer. Mytilus edulis and A. islandica appeared to tolerate wide ranges of sw temperature and pCO₂. Lipofuscin accumulation of M. edulis increased with temperature while the C_i decreased, but shell growth of the mussels only sharply decreased while its mortality increased between 20 and 25 °C. In A. islandica, lipofuscin accumulation increased with temperature, whereas the C_i, shell growth and shell breaking force decreased. The pCO₂ treatment had only marginal effects on the measured parameters of both bivalve species. Shell growth of both bivalve species was not impaired by under-saturation of the sea water with respect to aragonite and calcite. Furthermore, independently of water temperatures shell breaking force of both species and shell growth of A. islandica remained unaffected by the applied elevated sw pCO₂ for several months. Only at the highest temperature (25 °C), growth arrest of M. edulis was recorded at the high sw pCO₂ treatment and the C_i of M. edulis was slightly higher at the medium sw pCO₂ treatment than at the low and high sw pCO₂ treatments. The only effect of elevated sw pCO₂ on A. islandica was an increase in lipofuscin accumulation at the high sw pCO₂ treatment compared to the medium sw pCO₂ treatment. Our results show that, despite this robustness, growth of both M. edulis and A. islandica can be reduced if sw temperatures remain high for several weeks in summer. As large body size constitutes an escape from crab and sea star predation, this can make bivalves presumably more vulnerable to predation—with possible negative consequences on population growth. In M. edulis, but not in A. islandica, this effect is amplified by elevated sw pCO₂. We follow that combined effects of elevated sw pCO₂ and ocean warming might cause shifts in future Western Baltic Sea community structures and ecosystem services; however, only if predators or other interacting species do not suffer as strong from these stressors.     

Male dimorphism, sperm traits and immunology in the corkwing wrasse (Symphodus melops L.)

The evolution of alternative male mating phenotypes inevitably involves variation in risk or intensity of sperm competition. Males that typically mate in disfavoured roles (i.e. sneakers/parasitic males) are predicted to experience higher magnitudes of sperm competition than males mating in favoured roles (preferred by females/exhibiting mate monopolisation). Here, we investigated whether two distinct male phenotypes in corkwing wrasse (Symphodus melops) differ with respect to adaptations for sperm competition in terms of sperm quantity, sperm motility and fertilising capacity. We found that males exhibiting female mimicry (disfavoured role) had both absolutely and relatively larger gonads than males with typical secondary sexual characters (favoured role). Moreover, a higher proportion of sperm from female mimics was motile 5 min after activation compared to sperm of territorial males. There were, however, no differences in sperm concentration or in in vitro fertilisation ability between the two male morphs. We also examined whether the male phenotypes differed in some immune parameters and if any such variation is associated with sperm traits. Current theories predict that ejaculate quality should be negatively correlated with the level of immunocompetence. Territorial males had relatively heavier spleens than female mimics, but whether this reflects differing immunocompetence is uncertain, since the spleen is also an important organ for erythrocyte storage. Furthermore, there were no differences in the densities of circulating lymphocytes or granulocytes, and the immune parameters did not covary with the sperm traits. Differences in immunocompetence are therefore unlikely to provide a major proximate explanation for variations in sperm traits in corkwing wrasse.     

Cadmium accumulation by green algae Cladophora glomerata (L.) Kutz. (Chlorophyta) in presence of Nile tilapia Oreochromis niloticus (L.)

Accumulation of metals by aquatic organisms is mostly affected by other biological components in environments. In this study, cadmium (Cd) accumulation in green algae, Cladophora glomerata (L.) Kutz., exposed to 0.1 and 1.0 mg L^?1 of Cd for 15 and 30 days was examined in laboratory conditions in the presence of Nile tilapia Oreochromis niloticus (L.). The green algae C. glomerata accumulated Cd concentrations as 690 ± 70 and 3430 ± 470 mg kg^?1 on day 15, and 1130 ± 180 and 6830 ± 1540 mg kg^?1 on day 30. There were significant increases (p < 0.05) in metal accumulation by green algae as the exposure time and metal concentration increased. The results also indicated that the presence of Nile tilapia in the medium led to a significant Cd accumulation in the green algae compared to control (p < 0.05).     

Risk-sensitive foraging in common shrews (Sorex araneus L.)

Summary Risk-sensitive foraging theory predicts that predators which face starvation if there is a temporary shortfall in their food supply should choose feeding sites on the basis of variation in as well as mean expected reward rate. For a given mean reward rate they should choose high variance feeding sites (be risk-prone) if they are running below energy requirement, but low variance sites (be risk-averse) if they are running above.Common shrews presented with a choice between constant and variable feeding stations were more likely to visit the variable station when they were running below energy requirement and more likely to visit the constant station when they were running above. However, the tendency towards risk-aversion above requirement was greater than that towards risk-proneness below.When all shrews were considered together, the probability of visiting the variable station correlated negatively and continuously with intake relative to requirement.     

Foraging behavior of juvenile Carcinus maenas (L.) and Cancer pagurus L.

Information concerning the way juvenile crabs choose their diet from a variety of prey types can be useful for a better understanding of community dynamics, as well as for the adequate management of natural resources. Prey size and species selection by juvenile Carcinus maenas (15-35 mm carapace width, CW) and Cancer pagurus (20-40 mm CW) feeding on four bivalves of contrasting shell morphology were investigated. When offered a wide size range of Mytilus edulis, Ostrea edulis, Crassostrea gigas, and Cerastoderma edule presented individually, crabs generally showed evidence of size-selective predation. Cancer pagurus selected larger mussels relative to the size of their chelae (relative prey size, RPS) than did Carcinus maenas of similar and even larger carapace width. However, the RPS of selected O. edulis and Cerastoderma edule were similar for all crabs, suggesting that certain prey features constitute effective barriers even to the powerful chelae of Cancer pagurus. When offered a wide size range of mussels and oysters simultaneously, all crabs consistently selected mussels. When offered O. edulis and Crassostrea gigas, crabs consumed both these oyster species in similar numbers. Carcinus maenas consumed similar numbers of mussels and cockles; Cancer pagurus, however, showed no preference for either prey in the smaller size classes but selected more mussels than cockles as prey increased in size. Although previous studies report that adult Carcinus maenas select prey species according to their profitability (amount of food ingested per unit of handling time, milligrams per second), consumption rates of the size classes of prey selected by juvenile shore crabs did not always parallel prey value. Although variations in crab strength can account for many of the differences between the foraging strategy of juvenile and adult C. maenas, our results suggest that juvenile crabs are less species selective than adults as a result of the restrictions imposed on small individuals that have limited access to larger prey.     

Play behavior and exercise in young ponies (Equus caballus L.)

Summary Play behavior of young ponies accounted for two-thirds of total running exercise and over 95% of all high-speed turns in ten animals from birth to age six weeks. The classical supposition, never previously demonstrated, that most exercise of young mammals occurs in play, is confirmed in these subjects.     

Antimony uptake by <Emphasis Type="Italic">Zea mays</Emphasis> (L.) and <Emphasis Type="Italic">Helianthus annuus</Emphasis> (L.) from nutrient solution

We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans.     

The uptake and translocation of selected elements by cole (Brassica) grown using oasis soils in pot experiments

Pot experiments were conducted on cole (Brassica) grown in soils jointly treated with traces of two heavy metals cadmium (Cd) and zinc (Zn). As the concentration of heavy metals in the soil increased, the uptake of these metals by the plants rose. However, the ratio of heavy metal concentration in soil to uptake by plants increased at a slower rate. Bioavailability of heavy metals considered between the roots and soil using non-linear regressions was shown to be statistically significant. Similarly, the bioavailability of these two heavy metals between leaves and roots using a linear regression was also statistically significant. The bioconcentration factors (BCFs) for Cd and Zn were 0.282 and 4.289, respectively. Significant variation of BCF with the heavy metal bioavailability in soil was noted from non-linear models. The transfer factors (TFs) were 4.49 for Cd and 1.39 for Zn. The Zn concentration in leaves under all treatments did not exceed threshold set standards, but Cd levels exceeded these standards when the concentration of Cd in the soil was more than 1.92 mg kg^?1 dry weight (dw). Data indicate that cole (Brassica) is not a suitable crop for oasis soils because of plant contamination with heavy metals, especially Cd.     

Effects of nano-silicon and common silicon on lead uptake and translocation in two rice cultivars

The current study investigated the effects of nano-silicon (Si) and common Si on lead (Pb) toxicity, uptake, translocation, and accumulation in the rice cultivars Yangdao 6 and Yu 44 grown in soil containing two different Pb levels (500 mg·kg⁻¹ and 1000 mg·kg⁻¹). The results showed that Si application alleviated the toxic effects of Pb on rice growth. Under soil Pb treatments of 500 and 1000 mg·kg⁻¹, the biomasses of plants supplied with common Si and nano-Si were 1.8%–5.2% and 3.3%–11.8% higher, respectively, than those of plants with no Si supply (control). Compared to the control, Pb concentrations in rice shoots supplied with common Si and nano-Si were reduced by 14.3%–31.4% and 27.6%–54.0%, respectively. Pb concentrations in rice grains treated with common Si and nano-Si decreased by 21.3%–40.9% and 38.6%–64.8%, respectively. Pb translocation factors (TFs) from roots to shoots decreased by 15.0%–29.3% and 25.6%–50.8%, respectively. The TFs from shoots to grains reduced by 8.3%–13.7% and 15.3%–21.1%, respectively, after Si application. The magnitudes of the effects observed on plants decreased in the following order: nano-Si treatment>common Si treatment and high-grain-Pb-accumulating cultivar (Yangdao 6)>low-grain-Pb-accumulating cultivar (Yu 44) and heavy Pb stress (1000 mg·kg⁻¹)>moderate Pb stress (500 mg·kg⁻¹)>no Pb treatment. The results of the study indicate that nano-Si is more efficient than common Si in ameliorating the toxic effects of Pb on rice growth, preventing Pb transfer from rice roots to aboveground parts, and blocking Pb accumulation in rice grains, especially in high-Pb-accumulating rice cultivars and in heavily Pb-polluted soils.