Soil amidase activity in polyacrylamide-treated soils and potential activity toward common amide-containing pesticides

 Polyacrylamide (PAM) is currently used as an irrigation water additive to significantly reduce the amount of soil erosion that occurs during furrow irrigation of crops. Elevated soil amidase activity specific toward the large PAM polymer has been reported in PAM-treated field soils; the substrate specificity of the induced amidase is uncertain. PAM-treated and untreated soils were assayed for their capacity to hydrolyze the amide bond in carbaryl (Sevin), diphenamid (Dymid), and naphthalene acetamide. Based on results obtained with a soil amidase assay, there was no difference between PAM-treated and untreated soils with respect to the rate of amide bond hydrolysis of any of the agrochemicals tested. It appears that under these assay conditions the PAM-induced soil amidase is not active toward the amide bonds within these molecules. However, carbaryl was hydrolyzed by a different soil amidase. To our knowledge, this is the first soil enzyme assay-based demonstration of the hydrolysis of carbaryl by a soil amidase. Received: 23 June 1999     

香椿芽中亚硝酸盐含量的比较研究

采用盐酸萘乙二胺分光光度法对焯水椿芽、新鲜椿芽用食盐水腌渍一段时间后,测定其亚硝酸盐的含量,为人们的日常饮食、蔬菜加工提供科学依据^[1]。结果表明：香椿芽用开水焯过后其亚硝酸盐的含量有大幅度降低,且腌渍8天后,亚硝酸盐含量逐渐降低并趋于平稳,低温储存有利于亚硝酸盐含量的降低。     

Alterations in the brain monoaminergic neurotransmitters of rainbow trout related to naphthalene exposure at the beginning of vitellogenesis

The contents of dopamine (DA), noradrenaline (NA), serotonin (5HT), and some related metabolites were studied in different brain regions of rainbow trout at two different stages of sexual maturation (at the beginning of vitellogenesis), after naphthalene (NAP) administration. The effects of NAP varied according to duration of exposure, brain region and vitellogenesis stage of the trout, and were more significant during previtellogenesis. The changes observed in DA metabolism were generally stimulatory after exposure for 3 h, and either stimulatory or inhibitory (depending on the brain regions) after exposure for 3 days to NAP. NA levels were altered by NAP in various brain regions, but only during previtellogenesis. With respect to 5HT, treatment with NAP reduced levels of the amine and/or its main metabolite in most of the brain regions studied, particularly 3 h after treatment. The results suggest that NAP might interfere with the processes regulating brain monoamine metabolism, either locally or indirectly by altering steroid feedback to brain centres, and thus disrupt endocrine control of reproductive development through the brain–pituitary axis.     

萘乙酸对芥蓝根、芽生长的影响

以芥蓝种子为试材,研究不同浓度萘乙酸(NAA)营养液对芥蓝幼苗根、茎、芽生长的影响.结果表明:不同浓度的萘乙酸培养液对芥蓝的生长有不同的影响,即有不同程度的促进或抑制作用.其中0.001 mg/L NAA对侧根的生长表现出促进作用,同时对子叶生长也表现出促进作用,并且对根重和根长有促进作用;0.0001 mg/L对根重和根长有促进作用,但对侧根的生长(根数)没有促进作用;0.1～10 mg/L浓度范围内的NAA对芥蓝幼苗的生长有抑制作用,但10 mg/L对茎的加粗却表现出明显的促进作用.     

Efficient in vitro multiplication in Ornithogalum ulophyllum Hand.-Mazz. from twin scale explants

Ornithogalum ulophyllum Hand.-Mazz. with beautiful white flowers is an important medicinal and ornamental plant of the Middle Eastern countries and need exploitation for commercial propagation. The study reports in vitro mass proliferation of bulblets achieved from twin scales and “in vitro regenerated bulblet” explants on MS medium supplemented with various concentrations of BAP–NAA. The best regeneration on twin scales and “in vitro regenerated bulblets” was obtained on MS medium containing 2 mg l⁻¹ BAP–0.5 mg l⁻¹ NAA and 2 mg l⁻¹BAP–1 mg l⁻¹ NAA, respectively. However, bulb scales seemed to be more potent for bulblet regeneration. A large number of the developing bulblets rooted on the regeneration medium. Remaining non-rooting bulblets were rooted on MS medium containing 1 mg l⁻¹ NAA. All plants were acclimatized in the environmental chamber for 4 weeks and were transferred to the greenhouse for flowering. Regenerated bulblets developed into morphologically normal plants.     

The fate of C-naphthalene in soil microcosms containing Scots pine seedlings and enchytraeids

The fate of freshly spiked and aged ¹⁴C-naphthalene associated residues as investigated in the presence and absence of ectomycorrhizal Scots pine seedlings and enchytraeid worms, in a factorial experimental design. Microcosms were used which enabled the ¹⁴C-labelled naphthalene associated residues to be quantified, including plant lipids which acted as an additional naphthalene sink within the microcosms. The presence of plant roots altered the availability of the ¹⁴C-naphthalene and associated residues to degrading microbes. Mineralisation and volatilisation of ¹⁴C naphthalene in freshly spiked soil were lower in the presence of Scots pine. Conversely, in soil aged for 180 d, Scots pine increased mineralisation, and bioavailability of naphthalene. Root-mediated processes, microbial activity and enchytraeids interact with desorption, bioavailability and mineralisation of naphthalene.     

Effects on microflora of using naphthalene or X-rays to reduce arthropod populations in the field

Summary Naphthalene or X-rays are often used to test the effect on soil processes of reducing or eliminating arthropods. Naphthalene, however, is shown here to reduce radial growth significantly in eight out of nine basidiomycete fungi tested. X-ray treatment, which killed only 24% of Onychiurus latus Gisin (Collembola), significantly reduced the radial growth rate of one of two fungi tested. These techniques are likely to affect the composition of microbial communities and therefore should be used only with extreme caution in field manipulation experiments involving fauna-microflora interactions.Dedicated to the late Prof.Dr. M.S. Ghilarov     

萘胁迫对菖蒲生长和生理特性的影响

[目的]探寻菖蒲应用于多环芳烃污染修复的可行性。[方法]用人工配制不同浓度的含萘废水培养菖蒲,研究了萘胁迫对菖蒲生长和叶片叶绿素、脯氨酸、丙二醛含量的影响。[结果]萘胁迫下,菖蒲的株高和生物量增长均显著降低,叶片叶绿素含量显著上升,而脯氨酸含量和丙二醛含量在低浓度(5.0和10.0 mg/L)萘胁迫下变化不显著,在高浓度(20.0 mg/L)萘胁迫下显著上升。[结论]萘胁迫下菖蒲生长受到抑制,但菖蒲能抵抗较高浓度的萘胁迫,可以作为多环芳烃污染修复的植物种。     

阴-非离子表面活性剂对污染土娄土中菲和萘的洗脱

旨在以最少的增效试剂用量达到最大的增效修复效果,采用批处理方法,研究在临界胶束浓度(Critical Micelle Concentration,CMC)之下,阴离子表面活性剂SDS和非离子表面活性剂TritonX-100、Brij35和Tween80,以及在CMC浓度之上的Brij35和Tween80对污染土娄土中菲和萘总的洗脱效果。结果表明,在CMC以下,随着单一表面活性剂质量浓度的增大,菲和萘的总洗脱百分数逐渐增大,不同表面活性剂洗脱百分数大小顺序为SDSTween80TritonX-100Brij35,其洗脱机理主要归因于表面活性剂分子对疏水性有机物在水介质中溶解度的增加。混合表面活性剂对菲和萘污染土娄土具有较好的修复效果,其最佳洗脱质量浓度比为Tween80∶SDS=3∶5、TritonX-100∶SDS=1∶8、Brij35∶SDS为21∶200时,洗脱百分数达到100%。离子强度增加有利于增加SDS对菲和萘的洗脱百分数,而不利于增加非离子表面活性剂对菲和萘的洗脱百分数。质量浓度低于CMC的表面活性剂溶液以增溶的方式促进菲和萘从土壤中洗脱,阴-非离子表面活性剂混合使用可以高效净化土壤中的污染物菲和萘。     

萘乙酸对扁穗牛鞭草生长发育及地上部生物量的影响

以 “雅安”扁穗牛鞭草(Hemarthria compressa)为试材,研究不同的萘乙酸(NAA)浓度和浸泡时间对其生长发育及地上部生物量的影响。结果表明,NAA浓度对扁穗牛鞭草的生长速度、产量及第一茬刈割时的株高影响显著,其中低浓度NAA对上述性状有促进作用,高浓度则有抑制作用。此外,NAA浓度和浸泡时间对上述各性状的互作效应显著,以NAA浓度200 mg·L^-1,浸泡20 min处理后其生长表现最好,且增产效应持久,该处理为扁穗牛鞭草扦插繁殖最适宜的化学调控方法。