Effects of insecticide applications on macroinvertebrate density and biomass in rice-fields in the Rhône-delta,France

The density of 23 macroinvertebrate species and the total macroinvertebrate biomass were compared between rice-fields treated with lindane and diazinon in June and alphamethine in August and untreated controls. The macroinvertebrates could be divided into four groups: (1) Taxa, in which the densities were lower in the insecticide treatment in July and August than in the non-insecticide treatment. (2) The Culicidae which occurred in the insecticide treatment in significantly lower density in July, but in significantly higher density in August. (3) Ischnura elegans (Vander L.) which was found in July after the lindane application in significantly higher numbers in the insecticide treatments, but in significantly lower numbers in the insecticide treatment in August after the application of the pyrethroid. In these three groups, we assumed that direct effects due to the insecticides toxicity were the reason for the differences in density. (4) The fourth group included three taxa in which the densities were significantly higher in the insecticide treatment in July and August than in the control. For this, indirect effects due to reduced biotic interactions may be responsible. The biomass was higher in the insecticide treatments in July, mainly because of a high increase in gastropod density, during the rest of the season it was similar between treatments and controls.     

Effects of Feeding and Drinking on Acetylcholine Release in the Nucleus Accumbens, Striatum, and Hippocampus of Freely Behaving Rats

Extracellular levels of acetylcholine (ACh) were measured in the nucleus accumbens (NAC), striatum (STR), and hippocampus (HIPP) using microdialysis in 30-min intervals before, during, and after free-feeding in 20-h food-deprived rats. The effects on ACh in the NAC and STR were also observed in response to water intake in 20-h water-deprived animals. Neostigmine was used in the perfusate to improve ACh recovery. Basal ACh was sensitive to tetrodotoxin and low calcium, and therefore largely neuronal in origin. Feeding caused a 38% increase in extracellular ACh in the NAC and no change in the STR or HIPP. Dopamine was also increased in the NAC (48%) and to a lesser extent in the STR (21%) following feeding. Drinking caused 18-20% increases in ACh release in both the NAC and STR. In a separate experiment, ACh release in the NAC was monitored in 10-min intervals during free-feeding; ACh increased in the interval immediately following maximal food intake. These results suggest a site-specific increase in ACh release following feeding that cannot be solely attributed to the activation associated with this behavior.     

Effects of ammonium sulphate application on the rhizosphere,fine-root and needle chemistry in aPicea abies (L.) Karst. stand

Rhizosphere, fine-root and needle chemistry were investigated in a 28 year old Norway spruce stand in SW Sweden. The uptake and allocation pattern of plant nutrients and aluminium in control plots (C) and plots repeatedly treated with ammonium sulphate (NS) were compared. Treatments started in 1988. Current year needles, one-year-old needles and cylindrical core samples of the LFH-layer and the mineral soil layers were sampled in 1988, 1989 and 1990. Compared to the control plots, pH decreased significantly in the rhizosphere soil in the NS plots in 1989 and 1990 while the SO₄-S concentration increased significantly. Aluminium concentration in the rhizosphere soil was generally higher in the NS plots in all soil layers, except at 0–10 cm depths, both in 1989 and 1990. Calcium, Mg and K concentrations also increased after treatment with ammonium sulphate. Ammonium ions may have replaced these elements in the soil organic matter. The NS treatment significantly reduced Mg concentrations in fine roots in all layers in 1990. A similar trend was found in the needles. Ca concentrations in fine roots were significantly lower in the NS plots in the LFH layer in 1990 and the same pattern was found in the current needles. The N and S concentrations of both fine roots and needles were significantly higher in the NS plots. It was suggested that NS treatment resulted in displacement of Mg, Ca and K from exchange sites in the LFH layer leading to leaching of these cations to the mineral soil. Further application of ammonium sulphate may damage the fine roots and consequently adversely affect the water and nutrient uptake of root systems.     

Circadian rhythmic changes in the lipid composition of muscles in kilka <Emphasis Type="Italic">Clupeonella cultriventris</Emphasis> (Clupeidae,clupeiformes) during natural periodicity of feeding in the feeding and spawning periods in the Rybinsk Reservoir

According to data of observations in 2002–2004, differences in the pattern of diurnal fluctuations in the total content and fractional composition of lipids in muscles of mature specimens of kilka Clupeonella cultriventris from the Rybinsk Reservoir in the feeding and spawning periods were revealed. It was established that the feeding intensity in kilka considerably changes throughout 24 h in both periods of the annual cycle, while diurnal fluctuations in the fatness of muscles are distinctly manifested only in the reproductive period and have a dissimilar pattern in specimens of different sexes. In females and males, they are determined mainly by the change in the content of the fraction of reserve lipids-triacylglycerols, as a rule, by its increase in the light hours of the day, several hours after an increase in the feeding activity of fish. The pattern of diurnal fluctuations of the level of lipid fractions (phospholipids, triacylglycerols, cholesterol, and its ethers) in kilka’s muscles differs from that in the feeding period. Possible causes of the change of diurnal variations of the considered indices of lipid metabolism in kilka at an increase in the endocrine activity of its body in the reproductive period is discussed.     

果实膨大期喷布磷酸二氢钾对三月红荔枝果实贮藏性的影响

在三月红荔枝(Litchi chinensis cv.Sanyuehong)果实膨大期对树冠喷施0.2%磷酸二氢钾(KP)水溶液,以探讨磷酸二氢钾对荔枝果实贮藏性的影响。结果表明:(1) KP处理的果实在贮藏期前17d,失重率及果肉可溶性固形物、酸、VitC、花色素苷等指标的变化趋势与对照基本相似;(2) KP处理的果肉可溶性蛋白质含量变化与对照有明显差异,而果皮的可溶性蛋白质含量在贮藏期前10d变化动态与对照一致,此后呈相反的变化趋势;(3)果皮POD活性显著高于果肉,KP处理和对照的果肉POD活性在贮藏第3d后、果皮POD活性在第17d前分别具有相似变化趋势;(4)果肉中CAT活性在贮藏第3~17d期间都显著或极显著高于果皮,KP处理和对照果肉、果皮CAT活性动态变化均为单峰曲线。     

寄生在鲤鱼及草(鲩)鱼的鱊头槽绦虫的多样性

研究了寄生于鲤鱼及草(鲩)鱼的鱊头槽绦虫(Bothriocephalus acheiloghathi)的多样性.作者在1986-2000年收集材料,遍及中国19个省及自治区.在江苏等5省只收集到其它寄生虫的材料,故结果未列入附录1和2.研究结果表明,鲤鱼及草鱼的寄生鱊头槽绦虫的地理分布截然不同.寄生于鲤鱼的鱊头槽绦虫分布于黄河水系的西北地区及黑龙江水系的东北各省及长江上游的四川、云南和贵州,南方各省的鲤鱼不感染这种绦虫.寄生于草鱼的鱊头槽绦虫分布于沿珠江水系的广东、广西及闽江水系的福建,感染池塘的幼龄草鱼,天然水体中未发现感染阳性的草鱼.交义感染试验表明,寄生在这两种鲤科鱼类的头槽绦虫有极强的宿主特异性,草鱼感染的头槽绦虫一年内大部分时间排出发育完全的胚胎卵,而鲤鱼感染的头槽绦虫排出的虫卵多为早期分裂卵,甚至在盛夏,水温在28℃-30℃的情况下也无例外.虫卵发育程度不同,卵的孵化期也有差异.在同等温度28℃-29℃时,草鱼头槽绦虫虫卵的孵化期为1.69±0.17 d;鲤鱼的头槽绦虫虫卵的孵化期为3.98±0.3 d.此外,种群结构也有明显区别,草鱼的头槽绦虫在繁殖季节,体长＜1 cm的幼虫占种群的主体,年终时绦虫全部从宿主体内消失,生活周期从初染至消敛约1年;鲤鱼的头槽绦虫主体全年皆为孕节成虫,在Ⅱ龄商品鱼中继续繁殖.本研究表明,鲤鱼及草鱼的寄生鱊头槽绦虫显示的多样性是因长期适应不同生活环境从而演化为两个不同的亚种[动物学报 53(3):470-480,2007].     

Sex and estrous cycle-dependent differences in glial fibrillary acidic protein immunoreactivity in the adult rat hippocampus

Sex differences in the morphology and function of the hippocampus have been reported in several species, but it is unknown whether a sexual dimorphism exists in glial fibrillary acidic protein (GFAP) expression in the rat hippocampus. We analyzed GFAP immunoreactivity in the hippocampus of intact adult male rats as well as in females during diestrus and proestrus phases of the estrous cycle. We found that in CA1, CA3, and dentate gyrus, GFAP immunoreactivity was higher in proestrus females as compared with males and diestrus females. In CA1, a similar GFAP immunoreactivity was found in males and in diestrus females, but in dentate gyrus, males presented the lowest GFAP content. Interestingly, differences in astrocyte morphology were also found. Rounded cells with numerous and short processes were mainly observed in the hippocampus during proestrus whereas cells with stellate shape with few and long processes were present in the hippocampus of males and diestrus females. The marked sex and estrous cycle-dependent differences in GFAP immunoreactivity density and in astrocyte number and morphology found in the rat hippocampus, suggest the involvement of sex steroid hormones in the sexually dimorphic functions of the hippocampus, and in the change in its activity during the estrous cycle.     

Genetic variance in temperature dependent adult size deriving from physiological genetic variation at temperature boundaries

An increase in genetic variation in body size has often been observed under stress; an increase in dominance variance and interaction variance as well as in additive genetic variance has been reported. The increase in genetic variation must be caused by physiological mechanisms that are specific to adverse environments. A model is proposed to explain the occurrence of an increase in genetic variation in body size in Drosophila at extreme temperatures. The model has parameters specific to the low- and high-temperature regions of the viable range. Additive genetic variation in the boundary temperatures leads to a marked increase in additive genetic variation in development rate and body size at extreme temperatures. Additive genetic variation in the temperature sensitivity in the low- and high-temperature regions adds non-additive genetic variation. Development rate shows patterns in additive genetic variation that differ from the patterns of genetic variation in body size; therefore, the genetic correlation between development rate and body size changes sign repeatedly as a function of temperature. The existence of dominance in the genetic variation in the boundary temperatures or in the low- and high-temperature sensitivities leads to a higher total genetic variance due to higher dominance and interaction variance, for both development rate and body size. This revised version was published online in July 2006 with corrections to the Cover Date.     

Influence of in vitro factors on titre and elimination of model fruit tree viruses

The titre of apple chlorotic leaf spot virus (ACLSV) was higher in microplants of Malus domestica cv. Jonagold than in 2-year-old grafted scions. Cytokinin concentration in the medium increased the titre of prunus necrotic ringspot virus (PNRSV) in the apex of microplants of Prunus insititia cv. Kozlienka but did not affect the titre of ACLSV in M .domestica.Virus titre of ACLSVwas higher in the haulms of autotrophically-grown compared with heterotrophically-grown microplants whereas as for PNRSV the results were the reverse. For both viruses, however, titre of the virus in the roots of autotrophically-grown plants was significantly higher than in haulm tissue from heterotrophic cultures. Ribavirin incorporation resulted in elimination of both viruses. Negative ELISA results were confirmed independently by PCR. The efficacy of Ribavirin in elimination of ACLSV was increased by increasing the concentration of cytokinin in the medium in parallel with decreasing the concentration of Ribavirin. These results are discussed in the context of the reliability of in vitro virus testing.     

Preferential Induction of Alcohol Dehydrogenase in Coleoptiles of Rice Seedlings Germinated in Submergence Condition

Difference in the growth response to submergence between coleoptiles and roots of rice (Oryza sativa L.) was investigated in 9-d-old rice seedlings. The coleoptile length in the submergence condition was much greater than that in aerobic condition, whereas the root length in the submergence condition was less than that in the aerobic condition. Alcohol dehydrogenase (ADH) activity in the coleoptiles in the submergence condition was much greater than that in the aerobic condition, but ADH activity in the roots in the submergence condition increased slightly. These results suggest that the preferential ADH induction in rice seedlings may contribute to the difference in the growth response between the coleoptiles and roots under low oxygen conditions.