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1.
The eggs of Argas (Argas) reflexus (Fab.) were exposed to 0.05% colchicine on 9th, 15th or 23rd–25th days of embryonic development at 25°C and 30% RH. The eggs on the 15th and 23rd–25th days of development were the most sensitive to colchicine. In these experiments 6.9% and 9.4% embryos died, respectively. The largest number of disturbances of egg hatch (11.5%) were observed after exposure of the eggs to colchicine on 23rd–25th days of embryogenesis. 相似文献
2.
In two glasshouse studies Sesbania accessions were compared with a susceptible tomato cultivar as hosts to Meloidogyne javanica. Inoculating the growth medium with either infective juveniles or egg masses resulted in significant differences in root galling and egg mass production. The accessions could be grouped into moderate and poor hosts. Growth of roots was also depressed by the infestation. In a field study on a nematode infested site, significant variation in root galling was observed. Infestation was lower in plants growing on ridges than those on flat land. The studies indicate that continued cultivation of Sesbania may lead to a build up in soil root-knot nematode populations. 相似文献
3.
采用失重法及扫描电镜法研究了2-(3'-羟基苯基)-4,5-二(2’羟基苯基)咪唑(HHIP)在1MHCl溶液中对低碳铜的缓蚀作用,并对其缓蚀机理进行了探讨.研究结果表明:在1M HC1溶液中,该缓蚀剂对低碳钢的缓蚀效率可达到90%以上,最佳缓蚀效率达到95.12%,当缓蚀剂浓度为1mmol/L、实验温度为30℃,吸附成膜时间4h,缓蚀效率达最大值,此后基本不变.通过理论计算和分析该缓蚀剂在低碳铜的表面的吸附符合Langmuir吸附,且吉布斯自由能显示为自发过程. 相似文献
4.
In this study we investigated the effect of an ethanolic extract of propolis, with and without CAPE, and some of its components on cyclooxygenase (COX) activity. Propolis (0.00003-0.03%) significantly and concentration-dependently inhibited COX activity from lung homogenate of saline- or LPS-treated rats. Same results were obtained with CAPE (0.1-100 microM). COX activity from lung homogenate of saline- or LPS-treated rats was also inhibited by galangin (0.1-100 microM), although the inhibition induced by the lowest concentration was not significant. Caffeic, ferulic, cinnamic and chlorogenic acids and pinocembrin, (0.1-100 microM) did not affect COX activity. The inhibition curves showed that CAPE and propolis were equipotent inhibitors, whereas galangin was significantly (P<0.001) less potent than propolis and CAPE. In order to better investigate the role of CAPE, we tested the action of an ethanolic extract of propolis (0.00003-0.03%) without CAPE. This extract significantly and concentration-dependently inhibited COX activity from lung homogenate of saline- or LPS-treated rats, however, it resulted to be approximately 10 times less potent than the extract containing CAPE. The analysis of the inhibition curves of the extract with and without CAPE showed a significant (P<0.001) difference. These results suggest that both CAPE and galangin contribute to the overall activity of propolis, CAPE being more effective. 相似文献
6.
采用普查与定点调查相结合的方法,对太阳坪村果园主要病虫害种类及危害情况进行了系统调查。结果表明,危害太阳坪村水果生产的虫害主要有35种;病害主要有13种。其中危害较严重的病虫害为天牛、食心虫、褐腐病、烟煤病、黑斑病等。并对太阳坪村果园管理经营所存在的问题和防治对策进行了分析。调查结果为进一步制定绿色防控和经营措施,保障太阳坪村果树种植业的持续健康发展具有重要意义。 相似文献
7.
Two-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis and Fraxinus mandshurica were treated in open-top chambers with elevated CO 2 concentrations (700 μL·L −1, 500 μL·L −1) and ambient CO 2 concentrations (350 μL·L −1) in Changbai Mountain from June to Sept. in 1999 and 2001. The net photosynthetic rate, dark respiration rate, ribulose-1,5-bisphosphate
carboxlase (RuBPcase) activity, and chlorophyll content were analyzed. The results indicated the RuBPcase activity of the
three species seedlings increased at elevated CO 2 concentrations. The elevated CO 2 concentrations stimulated the net photosynthetic rates of three tree species except P. sylvestriformis grown under 500 μL·L −1 CO 2 concentration. The dark respiration rates of P. koraiensis and P. sylvestriformis increased under concentration of 700 μL·L −1 CO 2, out that of F. mandshurica decreased under both concentrations 700 μL·L −1 and 500 μL·L −1 CO 2. The seedlings of F. mandshurica decreased in chlorophyll contents at elevated CO 2 concentrations.
Foundation item: This paper was supported by the National Natural Science Foundation of China (No. 30070158). Knowledge Innovation Item of
Chinese Academy of Sciences (KZCX2-406) and “Hundred Scientists” Project of Chinese Academy of Sciences.
Biography: Zhou Yu-mei (1973-) Ph. Doctor, Assistant Research fellow Institute of Applied Ecology. Chinese Academy of Sciences. Shenyang
110016. P.R. China.
Responsible editor: Song Funan 相似文献
8.
以开顶箱的方式研究了长白山两年生红松、长白赤松、水曲柳幼苗,经过从1999年9月到2001年9月两个生长季高浓度CO2处理后,在700、500 L·L-1高浓度CO2和大气CO2条件下的净光合、暗呼吸速率,RuBP羧化酶活性及叶绿素含量变化。结果表明:红松、长白赤松和水曲柳幼苗在高浓度CO2下RuBP羧化酶活性增加;除500 L·L-1 CO2下的长白赤松幼苗外,高浓度CO2促进净光合速率;700 L·L-1 CO2使红松和长白赤松的暗呼吸速率升高,而水曲柳的暗呼吸在700、500 L·L-1CO2下降低。高浓度使水曲柳幼苗的叶绿素含量降低。 相似文献
9.
Topical application of cythion to the house cricket Gryllodes sigillatus affected the reproductive potential of both male and female. Control female mated with control male laid a maximum of 450 eggs and 95% of them hatched, whereas high concentration treated female mated with high concentration treated male laid 102 eggs and only 22% of them hatched. Regarding production and hatching of eggs, males were more significantly affected (p<0.01 and 0.001) by the treatment than the females (p<0.05 and 0.01). But when weights of eggs and newly hatched instars were considered, the effect (p<0.01) was same on both and sex has no value.
Zusammenfassung Eine topikale Anwendung von Cythion beiGryllodes sigillatus bewirkte eine Verringerung des Reproduktionspotentials bei beiden Geschlechtern. Kontroll-Weibchen, gepaart mit Kontroll-Männchen legtenmaximal 450 Eier, wovon 95% schlüpften. Dagegen produzierten Wiebchen, die mit hoher Cythion-Konzentration behandelt waren nach Paarung mit ebenfalls behandelten Männchen nur 102 Eier mit einer Schlüpfquote von nur 22%. Bezüglich Produktion und Eischlupfquote zeigte die Behandlung der Männchen deutlichere Wirkungen als die der Weibchen. Bei Betrachtung des Eigewichts und des Gewichts der jungen Larven ergaben sich jedoch gleich hohe Wirkungen, unabhängig vom Geschlecht.
With one table 相似文献
10.
The n-hexane and ethyl acetate extracts of whole plants of Dysophylla stellata significantly inhibited edema when applied topically at doses of 0.5 and 1 mg/ear in TPA-induced ear edema assay in mice. Further, both the extracts were evaluated for COX-1 and COX-2 inhibitory activities and showed 85.42 and 57.38%; and 71.79 and 89.27% inhibition at 50 µg/ml, respectively. Chromones ( 1 and 2) present in these extracts could be responsible for their COX-1 and COX-2 inhibitory and anti-inflammatory activities. The ethyl acetate extract showed antioxidant activity in DPPH and ABTS radical scavenging assay where as n-hexane extract found to be inactive. 相似文献
11.
Marigolds ( Tagetes erecta and T. patula) or sea ambrosia ( Ambrosia maritima) as intercropped plants with soybean ( Glycine max) cv. Giza 21 infected with Meloidogyne incognita, the root-knot nematode, significantly ( P0.05 and 0.01) reduced nematode numbers on soybean as indicated by the percentage reduction of galls, developmental stages and egg masses in roots and juveniles (J2) in soil. Marigolds significantly ( P0.05 or 0.01), in most cases, increased plant growth parameters of soybean, but sea ambrosia had an adverse effect on plant growth parameters. Addition of chopped green leaves of sea ambrosia to the soil planted to soybean significantly ( P0.05 and/or 0.01) reduced M. incognita reproduction and development. Sea ambrosia also had an adverse effect on soybean plant growth. 相似文献
12.
Abstract An extensive literature is available on browsing preference for certain tree species. However, useful predictive tools for estimating the impact of deer on forests production and biodiversity can still be improved. A step in that direction is not only to rank preference among tree species but also to quantify the relative risk of being browsed. The foraging selectivity of moose was evaluated using three different statistical methods developed to study habitat utilization. The general pattern for the three methods was consistent. From the results, groups of forage species were clustered and a quantitative index of selectivity was calculated for the groups. The selectivity index showed that rowan ( Sorbus aucuparia), willow ( Salix ssp.) and aspen ( Populus tremula) had a 14 times higher probability of being browsed than a group consisting of Scots pine ( Pinus sylvestris) and downy birch ( Betula pubescens), while juniper ( Juniperus communis) and silver birch ( Betula pendula) had a 3.5 times higher probability than Scots pine and downy birch. Since the most preferred species were the least abundant, one should be cautious about the generality of the index between areas, as it may indicate that preference depends on plant species composition. The method used can easily be applied in forest management. Information on quantitative selectivity indices may improve the possibility of managing moose in accordance with acceptable browsing damage. 相似文献
13.
Biochemical models of photosynthesis suggest that rising temperatures will increase rates of net carbon dioxide assimilation and enhance plant responses to increasing atmospheric concentrations of CO(2). We tested this hypothesis by evaluating acclimation and ontogenetic drift in net photosynthesis in seedlings of five boreal tree species grown at 370 and 580 &mgr;mol mol(-1) CO(2) in combination with day/night temperatures of 18/12, 21/15, 24/18, 27/21, and 30/24 degrees C. Leaf-area-based rates of net photosynthesis increased between 13 and 36% among species in plants grown and measured in elevated CO(2) compared to ambient CO(2). These CO(2)-induced increases in net photosynthesis were greater for slower-growing Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., and Larix laricina (Du Roi) K. Koch than for faster-growing Populus tremuloides Michx. and Betula papyrifera Marsh., paralleling longer-term growth differences between CO(2) treatments. Measures at common CO(2) concentrations revealed that net photosynthesis was down-regulated in plants grown at elevated CO(2). In situ leaf gas exchange rates varied minimally across temperature treatments and, contrary to predictions, increasing growth temperatures did not enhance the response of net photosynthesis to elevated CO(2) in four of the five species. Overall, the species exhibited declines in specific leaf area and leaf nitrogen concentration, and increases in total nonstructural carbohydrates in response to CO(2) enrichment. Consequently, the elevated CO(2) treatment enhanced rates of net photosynthesis much more when expressed on a leaf area basis (25%) than when expressed on a leaf mass basis (10%). In all species, rates of leaf net CO(2) exchange exhibited modest declines with increasing plant size through ontogeny. Among the conifers, enhancements of photosynthetic rates in elevated CO(2) were sustained through time across a wide range of plant sizes. In contrast, for Populus tremuloides and B. papyrifera, mass-based photosynthetic rates did not differ between CO(2) treatments. Overall, net photosynthetic rates were highly correlated with relative growth rate as it varied among species and treatment combinations through time. We conclude that interspecific variation may be a more important determinant of photosynthetic response to CO(2) than temperature. 相似文献
15.
A study was carried out to evaluate the growth parameters and nutritive qualities of Moringa oleifera, Millettia griffoniana and Pterocarpus santalinoides. The main objective of the study was to assess the potential of the MPTS in supplementing the feed of ruminant animals during
the dry season when grasses are scarce and their quality generally fall short of animal requirements. Leaf samples were randomly
collected from the trees for estimation of the proximate composition, neutral detergent fibre, acid detergent fibre and gas
production using the in vitro technique. Samples were collected three times to represent seasonal variations as follows: November:
Early Dry; February: Mid Dry and April: Late Dry seasons. Gas production was recorded at 3, 6, 9, 12, 15, 18, 21, 24, 48,
72 and 96 h of incubation. Mortality rate was less than 5%. M. oleifera recorded the best overall growth respectively followed by P. santalinoides and M. griffoniana. P. santalinoides and M. oleifera retained more leaves in the dry season than M. griffoniana. The dry matter (DM) and ether extract (EE) contents of the MPTS were significantly ( P < 0.05) affected by seasons and plant species while there were significant ( P < 0.05) species effects on the CP and ADF values. The gas production values and the fermentation parameters indicated the
presence of potentially degradable nutrients in the MPTS, which underscores the importance of the tree species as sources
of nutrient for ruminant animals during the dry season. 相似文献
16.
The diploid A. glutinosa (L.) Gaertn. is widespread throughout the European continent, except in the Iberian and Balkan Peninsulas where tetraploid populations have been discovered. We focused on the tetraploid species described as A. rohlenae Vít, Douda and Mandák that occupies the western part of the Balkan Peninsula, where it has likely completely replaced the diploid species. While the distribution range of the diploid A. glutinosa s. str. is well known, the exact distribution range of the tetraploid A. rohlenae is unknown. Here, we report the first exact distribution of the tetraploid A. rohlenae and the anticipated hybrid zones in which it is in contact with diploid populations using flow cytometry and morphometrics. Tetraploids are located primarily in the mountainous parts of the study area and towards the lowlands are gradually being replaced by diploids, forming a contact zone. We compare the main morphological characteristics of both species. Due to the geographical proximity of the study species, the morphological differences between them are clear outside the contact zones. However, within the contact zones, we recorded hybridisations that obscure the morphological differences between species, probably due to the presence of triploid hybrids.
相似文献
17.
The dimeric catechins dehydrotheasinensin A (2) and theacitrin C (3) were prepared from the oxidation of (−)-epigallocatechin-3-O-gallate (EGCG, 1), and their antioxidant activity was investigated using a chemiluminescence (CL) method in vitro. Both compounds showed significant inhibitory effects on reactive oxygen species (O 2−, H 2O 2 and •OH) and DNA oxidative damage, with 2 being more potent than 3 and EGCG itself. 相似文献
18.
This short report as a part of a broad work (Eur. J. For. Path. 15, 1985a) describes the isolation, the biological activity and the measurement of concentration of p-hydroxy acetophenone and its O-gluco-side (picein) by gas chromatography. p-hydroxy acetophenone was found to be phytotoxic to the 2-year-old saplings at a conc. of 500 ppm. The gas chromatographic measurement of p-hydroxy aceto-phenone (p-HAP) and its O-glucoside (after enzymic hydrolysis) in the current year's shoot parts showed the ratio p-HAP: p-HAP-O-glucoside always larger than 1 in the affected trees and less than 1 in the healthy trees. 相似文献
19.
以β-蒎烯为原料,先经氧化反应合成诺蒎酮,诺蒎酮与水杨醛进一步经羟醛缩合反应合成了3-(2'-羟基亚苄基)诺蒎酮,通过单因素和正交试验优化了缩合反应的工艺条件。结果表明:缩合反应的优化工艺条件为:诺蒎酮1.43 g,以30 m L叔丁醇为溶剂,2.5 g叔丁醇钾为催化剂,n(诺蒎酮)∶n(水杨醛)为1.0∶1.2,回流反应2 h,产物得率为79.46%。采用MS、IR、NMR、X射线单晶衍射等对3-(2'-羟基亚苄基)诺蒎酮的结构进行了表征,确认了化合物的结构,该化合物的晶体属单斜晶系,P212121空间群。对3-(2'-羟基亚苄基)诺蒎酮的酸碱指示性能进行了研究,结果表明:该化合物滴定0.257 4 mol/L盐酸标准溶液时,指示颜色为橘黄色,测定的盐酸浓度为0.259 6 mol/L,RSD为0.089%,滴定的灵敏度高、偏差小,效果优于酚酞指示剂。 相似文献
20.
研究了迹斑绿刺蛾幼虫对3种红树植物的取食选择性与叶片内含物含量的相关性。结果表明:处理1、2中迹斑绿刺蛾幼虫对无瓣海桑的取食量基本一致,均为7 cm2/头以上,且没有明显差异,其次为秋茄,取食量为3.99 cm2/头,不取食桐花叶片,说明无瓣海桑是迹斑绿刺蛾幼虫较理想的食物。内含物含量方面,可溶性糖含量最高的为桐花和秋茄,最低的为无瓣海桑,可溶性蛋白、游离氨基酸、总酚含量最高的为无瓣海桑,单宁含量最高的为桐花。相关分析表明,幼虫取食与叶片可溶性糖含量具有较好负相关性,与可溶性蛋白质、总酚含量具有较好的正相关,与游离氨基酸含量成较低正相关、与单宁含量呈较低负相关,说明叶片营养物质含量影响害虫取食的选择性,而次生性物质含量的变化又与虫害相互作用。 相似文献
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