首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The relative effect of parthenium (Parthenium hysterophorus L.) plant residue on growth of salvinia and paddy seedlings was studied. The inhibitory activity of the residue as shown by its effect on the number of healthy fronds (HFN) and biomass was in the order: flower and leaf > stem and root. The flower (FP) and leaf (LP) residue was lethal at and above 0.75% (w/v, the convention used throughout), and inhibitory at lower doses. The stem (SP) and root (RP) residue supported growth of salvinia at lower doses and were slightly inhibitory at higher (1.25%) dose. All the above residue types supported the growth of paddy seedlings except at 1.25%, the highest concentration tested, which was slightly inhibitory. The amounts of chlorophylla, b, total chlorophyll, and carotenoid pigments in the leaves of the paddy seedlings grown in the medium were comparable to the amounts in the leaves of seedlings grown in distilled water. This demonstrates beneficial effects of the treatments. The study shows that salvinia is more sensitive to allelochemicals released by FP and LP into the aqueous medium. Both salvinia and paddy responded similarly to SP and RP by supporting growth at lower doses, probably due to lower levels of inhibitors. The results are discussed with reference to the possible role of allelopathy by parthenium on the population dynamics of aquatic weeds in natural ecosystems.  相似文献   

2.
Parthenium (Parthenium hysterophorus L.) leaf residue (LP, leaf powder) inhibited salvinia (Salvinia molesta Mitchell) biomass and the number of healthy fronds at 0.25% (w/v) and killed the treated plants at and above 0.75% (w/v) in about 5–15 days, depending on the quantity of the residue. At the lethal dose, the LP caused an abrupt desiccation of above-water plant parts, probably due mainly to root dysfunction. This was concurrent with the loss of dehydrogenase activity in, and an increase in solute leakage from, the roots and loss of chlorophylla, b, and total chlorophyll contents in the fronds, resulting in death of the treated plants. The LP appears inhibitory to salvinia through affecting macromolecules—proteins, lipids, and nucleic acids. The inhibitory activity of LP at the lethal dose suspended in water was completely lost when allowed to stand for 30 days under outdoor conditions and promoted growth of the salvinia plants placed in it. The standard allelochemicals, including those present in parthenium LP, except parthenin andp-hydroxybenzoic acid, did not inhibit growth up to 100 ppm. However, parthenin andp-hydroxybenzoic acid killed salvinia plants at 100 and 50 ppm, respectively. Sincep-hydroxybenzoic acid is unlikely to be present at such a high concentration, parthenin appears to be one of the main allelochemicals responsible for the inhibitory effect of parthenium leaf residue on salvinia.A portion of this work was presented at the International Symposium on Weed Management for Sustainable Agriculture held at C.C.S. Haryana Agricultural University, Hissar, India, November 18–20, 1993.  相似文献   

3.
6种常用杀虫剂对萝卜蚜的毒力测定及田间防效   总被引:3,自引:0,他引:3  
[目的]采用室内毒力测定和田间药效试验方法,测定6种药剂对萝卜蚜的敏感性。[结果]结果表明萝卜蚜对不同类型杀虫剂敏感性有较大差异,其中95%毒死蜱对萝卜蚜杀虫活性最高,LC50值为0.1215 mg/L,其次为94%阿维菌素,LC50值为0.7795 mg/L,95%高效氯氰菊酯的敏感性最低,LC50值为996.8046 mg/L。通过田间试验可知:10%吡虫啉可湿性粉剂、1.8%阿维菌素乳油、3%啶虫脒可湿性粉剂、1%甲氨基阿维菌素苯甲酸盐乳油、40%毒死蜱乳油和4.5%高效氯氰菊酯乳油对萝卜蚜的防效都非常好,3 d的防效均达98%以上,14 d的防效为100%。[结论]在测试的6中药剂中,目前田间萝卜蚜与桃蚜相比具有较低的抗药性水平。  相似文献   

4.
Maysin, a flavone glycoside from corn silks, inhibits ingestion, and thus growth, ofHeliothis zea (Boddie) larvae. Pinitol from soybeans inhibitedH. zea growth by the same mechanism. Despite the widely held assumption that tannins inhibit growth by inhibiting assimilation, cotton condensed tannin inhibitedH. zea growth by reducing ingestion; no evidence was found for a reduction in assimilation. Neonate larvae are shown to be much more sensitive to allelochemics than larvae that have fed on control diet before being transferred to diet containing plant allelochemics.Reference to a company and/or product named by the department is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others which may also be suitable.Published with the approval of the director of the Delaware Agricultural Experiment Station as Miscellaneous Paper No. 968, Contribution No. 514 of the Department of Entomology and Applied Ecology, University of Delaware, Newark, Delaware 19711.  相似文献   

5.
Catalytic oxidation of trichloroethylene (TCE) and trichloromethane (TCM) oxidized alone and in two-component mixtures with selected volatile organic compounds (VOCs) such as toluene, n-hexane, ethanol or acetone was investigated over a Pt-Pd-based catalyst on a monolithic, metallic, γ-Al2O3-washcoated support. TCE and TCM were more difficult to oxidize than VOCs and temperatures of their 50% conversion (T50%) amouted to 420 and 330 °C, respectively. All the VOCs added were found to enhance the conversion of the two chlorinated compounds, drecreasing T50% by 20 °C, at the most, for TCM in the presence of toluene and by 50 °C for TCE in the presence of acetone. Both the chlorinated compounds lowered the conversion of the VOCs added (except that of toluene), and this lowering was particularly distinct with n-heptane; they also raised the concentration of acetaldehyde formed during the oxidation of oxyderivative compounds.  相似文献   

6.
顾菲  李永伟 《广东化工》2012,39(13):40-41
在对双氨基雄甾烷类化合物构效关系研究的基础上,合成了2个哌啶类双氨基雄甾烷类化合物,并对合成的过程和活性测定的结果进行了分析,以期发现更加有效或毒副作用更小的肌松药。化合物的结构均经1H NMR和13C NMR确证。  相似文献   

7.
张永生  陈维君 《化学与粘合》2010,32(2):11-12,49
采用烷氧基硅烷单体和钛酸四丁酯(TBOT)进行水解缩合,制得元素有机硅树脂聚钛硅氧烷(TiSi),再将聚钛硅氧烷与酚醛树脂(PF)进行脱水缩合,制得元素有机硅改性酚醛树脂(TiSiP)。利用红外光谱对得到的TiSi、PF和TiSiP的结构进行了表征,利用TG对TiSiP树脂的耐温性能进行了考察。所合成的树脂经180℃固化3h后,在空气气氛中300℃时开始出现明显的热失重,700℃时的残留率为64%。  相似文献   

8.
BACKGROUND: TiO2 heterogeneous photocatalysis should be optimized before application for the removal of pollutants in treated wastewaters. The response surface methodology (RSM) and artificial neural networks (ANNs) were applied to model and optimize the photocatalytic degradation of total phenolic (TPh) compounds in real secondary and tertiary treated municipal wastewaters. RESULTS: RSM was developed by considering a central composite design (CCD) with three input variables, i.e. TiO2 mass, initial concentration of TPh and irradiation intensity. At the same time a feed‐forward multilayered perceptron ANN trained using back propagation algorithms was used and compared with RSM. Under the optimum conditions established in experiments ([TPh]0 = 3 mg L?1; [TiO2] = 300 mg L?1; I = 600 W m?2) the degradation for both TPh and total organic carbon (TOC) followed pseudo‐first‐order kinetic model. Complete degradation of TPh took place in 180 min and reduction of TOC reached 80%. A significant abatement of the overall toxicity was accomplished as revealed by Microtox bioassay. CONCLUSIONS: It was found that the variables considered have important effects on TPh removal efficiency. The results demonstrated that the use of experimental design strategy is indispensable for successful investigation and adequate modeling of the process and that ANNs gave better modelling capability than RSM. Copyright © 2012 Society of Chemical Industry  相似文献   

9.
张静  毛桂洁  王铭琦 《精细化工》2014,31(5):607-611
以取代苯酚为原料亲核取代制得取代苯氧乙酸,采用硅胶负载四氯化锡为催化剂,二甲苯为溶剂,与二乙氨基乙醇发生酯化反应合成了6个苯氧乙酸二乙氨基乙醇酯衍生物。利用IR、1HNMR、13CNMR和MS对其结构进行了表征。初步的活性测试表明:与2,4-D(2,4-二氯苯氧乙酸)相比,大多数目标化合物均可促进玉米幼苗生长,提高玉米幼苗的硝酸还原酶活性,其中2-溴苯氧乙酸二乙氨基乙酯的处理质量浓度为20 mg/L时玉米幼苗硝酸还原酶活性最高。  相似文献   

10.
The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O(2) (-)·radical, DPPH, and the ABTS(+) radical scavenging activity assays were used to identify the antioxidant activities of Actinidia extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the Actinidia kolomikta extract had a higher antioxidant activity than the other two Actinidia extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (R(2) ≥ 0.712, p < 0.05). The Actinidia arguta extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that Actinidia extracts can potentially have health benefits.  相似文献   

11.
Olfactory attraction of female diamondback moths (Plutella xylostella) to odors of intact and homogenized host plants, as well as individual compounds characteristic of host plants, were investigated by behavioral and electrophysiological methods. Moths were attracted to odors ofBrassica juncea andB. napus seedlings in a Y-tube bioassay. Solvent fractions of homogenizedB. juncea leaves were attractive to moths whether or not isothiocyanates (IC) were present. Moths were attracted in Y-tube bioassays and to field traps baited with individual ICs. Volatiles fromB. juncea andB. napus elicited an electroantennogram (EAG) response and were attractive in the Y-tube bioassay. Allyl IC was shown to be the attractive component in homogenized plant volatiles but was found to be virtually absent from intact plant volatiles. Gas chromatographic fractionation of intact plant volatiles revealed a terpene-containing fraction to be most attractive to the moths. We were unable to isolate individual attractive compounds from this fraction. Our results suggest that certain elements of this fraction, possibly in combination, are important olfactory cues for host-plant finding by the diamondback moth with mustard oils playing an important and possibly synergistic role, particularly when plants are damaged.  相似文献   

12.
The inhibitive action of valeronitrile, benzonitrile and derivatives of benzonitrile on the corrosion and hydrogen embrittlement behaviour of HSLA steel in 0.5m H2SO4 was investigated. All these inhibitors reduced the corrosion rate of the steel with naphthonitrile showing the highest inhibitive efficiency and valeronitrile the lowest. All the inhibitors adsorbed on the steel as per the Temkin adsorption isotherm. The steel become less active on the addition of benzonitrile, 3-chlorobenzonitrile, 4-chlorobenzonitrile, 4-methylbenzonitrile and naphthonitrile to the acid while valeronitrile and 2-chlorobenzonitrile made the steel more active. Naphthonitrile reduced the rate of the hydrogen evolution reaction most efficiently. Derivatives of benzonitrile inhibited hydrogen absorption most effectively.  相似文献   

13.
在机械研磨(MM400)无溶剂条件下,用连二亚硫酸钠(保险粉)在1h内可以将各种芳香硝基化合物以中等到近定量的产率(79%~95%)还原成相应的胺。该转化在室温下以较高的化学选择性高效完成,反应的后处理及分离纯化操作简单。所有产物通过熔点、红外及核磁共振氢谱进行了表征。  相似文献   

14.
Oviposition by the leafhopperAmrasca devastans (Distant) on its susceptible host plant, cotton (Gossypium hirsutum var. PS-10), was inhibited by the volatiles of certain plants and by the vapors of some chemicals occurring in various plants when these were presented at a distance from the ovipositional substrate. The effectiveness of the volatiles of the plants for inhibiting the oviposition decreased in the order: eucalyptus > coriander=castor=tomato > lime,Ocimum being without effect. Among the volatile plant chemicals tested, the inhibitory effects decreased in the order: citral=carvacrol > citronellol=farnesol = geraniol=eucalyptus oil > neem oil=Cymbopogan oil. These chemicals served as volatile antiovipositants and did not reduce the arrival/stay of the insects on the host plants. Carvacrol had a slight toxic effect on the nymphs, but none of the volatiles was toxic to the adults.Homoptera: Cicadellidae.  相似文献   

15.
增产胺的合成与应用   总被引:1,自引:0,他引:1  
朱思成  傅金民 《农药》1995,34(12):6-7
在相转移条件下合成了增产胺,产率达94%。田间实验表明,增产胺对大豆具有增加光合作用,促进生长,增花增英,大幅度提高单产的作用。大豆亩产增加31.4%;大豆的质量明显改善,蛋白质和脂肪含量分别提高15.34%和6.58%。  相似文献   

16.
废氨气(水)回收及精制技术的开发与应用   总被引:2,自引:0,他引:2  
介绍处理化工生产过程中驰放地氨气(水)的工艺流程,技术特点,工程投资与效益分析。  相似文献   

17.
钟勤  钟万  钟国清  张艳 《精细化工》2011,28(5):471-474
以L-丙氨酸或L-亮氨酸及水杨醛、乙酸锌为原料,通过无溶剂一步法合成了氨基酸水杨醛席夫碱锌(Ⅱ)配合物[ZnL(H2O)].nH2O(L=sal-ala,sal-leu),用EDTA滴定法、元素分析、红外光谱、X射线粉末衍射、热分析等手段对配合物的组成和结构进行了表征。结果表明,锌分别与席夫碱配体中的亚氨基氮、羧基氧、酚羟基氧以及水分子中的氧形成了配位数为4的配合物,其热分解包括失水、配体的氧化分解过程,最后完全分解为氧化锌。  相似文献   

18.
The structural and biosynthetic diversity of allelochemicals in plants is thought to arise from selection for additive toxicity as a consequence of toxin mixture or for enhanced toxicity as a result of synergism. In order to understand how insects cope with this type of plant defense, we tested the effects of some allelochemicals in host plants of the black swallowtail Papilio polyxenes on the xanthotoxin-metabolic activity of CYP6B1, the principal enzyme responsible for the detoxification of furanocoumarins in this caterpillar. Additionally, the effects of some synthetic compounds not normally encountered by P. polyxenes on CYP6B1 were tested. These studies demonstrate that the integrity of furanocoumarin structure is important for competitive binding to the active site of CYP6B1, even though the carbonyl group on the pyranone ring apparently does not affect its inhibitory capacity, as in the case of furanochromones. Angular furanocoumarins are generally less phototoxic to many organisms than linear furanocoumarins due to their reduced capacity for cross-linking DNA strands, yet they are more toxic than linear furanocoumarins to black swallowtail larvae. This enhanced toxicity in vivo may be due to the ability of angular furanocoumarins to bind to the active site of CYP6B1 without being rapidly metabolized. This binding reduces the availability of CYP6B1 to metabolize other linear furanocoumarins. The structure-activity relationships for methylenedioxyphenyl compounds, flavonoids, imidazole, and imidazole derivatives are also discussed in light of their capacity to inhibit the xanthotoxin-metabolic activity of CYP6B1.  相似文献   

19.
钯催化下BER对羰基化合物和苯乙烯的竞争还原   总被引:1,自引:1,他引:0  
陈静  谌英武 《化学试剂》1993,15(5):268-269,279
用KBH4与717^#阴离子交换树脂反应制备了聚合物支载的硼氢化试剂(BER)。在二氯化钯催化下用BER对多种含羰基的化合物分别与苯乙烯的混合液(摩尔比1:1)进行了还原。且对BER还原羰基化合物和苯乙烯的竞争还原规律作了初步探讨。  相似文献   

20.
The parasitoid wasp Encarsia smithi is an important agent in the classical biological control of two species of invasive spiny whiteflies, Aleurocanthus spiniferus and Aleurocanthus camelliae. To evaluate the performance of parasitism indexed by genetic diversity, a highly polymorphic genetic marker is required. In this report, nine microsatellite loci are described for E. smithi. The microsatellite loci were obtained through the construction of an enriched library and exhibited polymorphisms (2–6 alleles per locus) and high levels of expected heterozygosities (0.203–0.780, average 0.537). Linkage disequilibrium and null alleles were not detected in these microsatellite loci. The isolated microsatellite markers may be useful to estimate the genetic diversity of E. smithi.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号