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 421 毫秒
1.
The endurance of the antibacterial properties of compounded papers containing wasted green tea leaves needs to be examined before considering these papers for long-term use. Hence, compounded papers containing 60 wt% wasted green tea leaves were irradiated for 1–200 h using a xenon lamp to examine the effect of irradiation on antibacterial properties of the paper. Irradiation for 20 h (cumulative ultraviolet dose at 365 nm, 6.67 × 106 J/m2) or longer was found to greatly increase the antibacterial activity of the paper to a level at which no bacterial cell was confirmed to be viable. The paper was also covered with various glass filters and irradiated for 1 h. Irradiation exclusively with visible rays did not significantly affect the antibacterial activity of the paper, whereas irradiation exclusively with ultraviolet rays, even for a short time, greatly increased the antibacterial activity.  相似文献   

2.
Composite paper containing waste tea leaves was prepared to investigate the effective utilization of waste tea leaves as deodorant material. Paper containing waste green tea leaves did not have increased deodorizing ability compared with controls either against acidic odors such as hydrogen sulfide and acetic acid gases or against neutral odors such as formaldehyde and acetaldehyde gases. In contrast, the paper had excellent deodorizing ability against basic odors such as ammonia and trimethylamine gases. It was observed during additional tests conducted on paper samples containing 60 wt% waste leaves of oolong tea, black tea, pu-erh tea, or hojicha, that all the samples reduced the ammonia concentration to below 1 ppm, which is the threshold concentration for olfactory recognition, within 30 min. Further, paper containing waste green tea leaves was found to decrease the odor residual rate to 5.1% in 30 min even for a waste tea leaf content of 10 wt%. The excellent deodorizing ability of the paper could be attributed to the chemical reactions between odorous substances and the catechins found in tea leaves. After the deodorization of ammonia, paper containing waste green tea leaves was found to have increased antibacterial activity against Staphylococcus aureus.  相似文献   

3.
Ranchers need alternative livestock feeds when herbaceous forages become limiting in summer. Our objectives were to determine: (1) leaf and stem biomass components, (2) nutritive value [in vitro dry matter digestibility (IVDMD), total nonstructural carbohydrate (TNC), N, and N digestibility] of leaves for animal browse, (3) concentration of the secondary metabolites robinin and mimosine, and (4) in vitro leaf and bark toxicity for black locust (Robinia pseudoacacia L.) and mimosa (Albizia julibrissin Durz.), respectively, pollarded at 50 cm in Arkansas, USA. Black locust exceeded mimosa for every yield component (leaf mass tree−1, leaves shoot−1, shoots tree−1, shoot mass tree−1, stem basal area, and biomass tree−1) except mass leaf−1. Projected yields were 1,900 and 1,600 kg leaves ha−1 for black locust and mimosa, respectively, assuming a population of 12,300 trees ha−1. Mimosa leaves had greater IVDMD, TNC, and N digestibility than black locust. Mimosa leaves exceeded the nutritional N requirements of growing cattle (Bos taurus L.) and goats (Capra hircus L.), but protein supplementation would be needed for growing goats grazing black locust leaves. Tissue concentrations of secondary metabolites robinin and mimosine were below detectable limits in black locust and mimosa, respectively. The extract of black locust bark, but not leaves, was toxic to bioassayed African green monkey (Cercopithecus aethiops L.) cells. Either black locust or mimosa could provide moderate quantities of high quality, rotationally grazed forage for goats during summer months when herbaceous forage may in short supply.  相似文献   

4.
Polyphenols occurring in cocoa, coffee and tea can have a role in the prevention of cariogenic processes, due to their antibacterial action. Cocoa polyphenol pentamers significantly reduce biofilm formation and acid production by Streptococcus mutans and S. sanguinis. In the same way, trigonelline, caffeine and chlorogenic acid occurring in green and roasted coffee interfere with S. mutans adsorption to saliva-coated hydroxyapatite beads. Studies carried out on green, oolong and black tea indicate that tea polyphenols exert an anti-caries effect via an anti-microbial mode-of-action, and galloyl esters of (−)-epicatechin, (−)-epigallocatechin and (−)-gallocatechin show increasing antibacterial activities. The anti-cariogenic effects against α-haemolytic streptococci showed by polyphenols from cocoa, coffee, and tea suggest further studies to a possible application of these beverages in the prevention of pathogenesis of dental caries.  相似文献   

5.
To estimate the importance of leaching of dissolved organic matter (DOM) as a pathway through which organic matter is supplied to stream ecosystems, we examined the amount of leachate over time and chemical properties of DOM leached from leaves in different conditions. The samples used were green leaves, yellow senescent leaves, and leaf litter of Salix gracilistyla Miq., which is the dominant riparian plant species in the middle reaches of rivers in western Japan. We analyzed dissolved organic carbon (DOC), total sugar, and polyphenol in the leachate of leaf samples collected from a fluvial bar in the middle reaches of the Ohtagawa River in Hiroshima Prefecture, Japan. Considerable leaching of DOC from senescent leaves [37.3 mg g−1 dry weight (dw) leaf] and leaf litter (8.1 mg g−1 dw leaf) occurred within 24 h after immersion. In contrast, DOC leached from green leaves was negligible until 1 week after leaf immersion. Carbon loss of leaves by leaching within 24 h after leaf immersion was estimated to be less than 8%, suggesting that leaching of DOC from S. gracilistyla leaves is a minor pathway through which organic matter is supplied to stream ecosystems. DOM leached from the leaves included sugar and polyphenol, which were among the major chemical forms of DOM leached from the leaves (based on the molecular mass). In a laboratory experiment in which the difference in the stability of DOM between the chemical forms was examined, sugar decomposed more rapidly than polyphenol.  相似文献   

6.
The leaves of Senna racemosa yielded the piperidine alkaloid cassine and an inositol methyl ether. Antimicrobial screening of the compounds revealed antibacterial activity of cassine with minimum inhibitory concentrations of 2.5 mg/ml for Staphylococcus aureus and Bacillus subtilis and 5.0 mg/ml for Candida albicans.  相似文献   

7.
Protoplasts were isolated from the leaves of sterile plants ofPopulus euphratica Oliv. by using 1% Cellulase “Onozuka” RS and 0.25% Pectolyase Y-23 in 0.6m of mannitol solution. Protoplasts were cultured in modified Murashige and Skoog's (MS) medium which contained no ammonium ions but was supplemented with BAP (6-benzylaminopurine), 2,4-D (2,4- dichlorophenoxy-acetic acid), and 1% sucrose at the cell density of 9×104/ml. Cell divisions occurred in every culture medium, especially in the medium containing 0.5 mg/l of BAP and 0.1 mg/l of 2,4-D, in which callus was successfully induced by successive culture through cell cluster formation. Shoots were regenerated from the callus, and their growth was enhanced on 1/2 MS medium containing 0.8 mg/l of BAP. Finally, shoots were rooted and plantlets were regenerated on 1/2 MS medium without a hormone. A part of this paper was presented at the 106th Annual Meeting of the Jpn. For. Soc. (1995).  相似文献   

8.
Two Rotstop® preparations, one containing a Phlebiopsis gigantea strain from Finland (Rotstop F) and the other one from Sweden (Rotstop S), were used in different concentrations to treat thinning stumps of Picea abies against spore infections by Heterobasidion spp. in southern Sweden. Trees were cut on three sites during the summer of 2004, and 285 stumps were treated manually ensuring 100% coverage. Spore concentrations in the treatment suspensions were ca 5 × 106 and 10 × 106 spores/l, and approximately 10 ml of suspension was applied per 100 cm2 of stump surface. An additional 31 stumps on one of the sites were treated mechanically with Rotstop S; in this treatment the spore concentration was high, about 20 × 106 spores/l, but the coverage was incomplete. Three months later there was a significant reduction in frequency and relative areas of Heterobasidion spp. infections on stumps with manual treatment compared with the untreated stumps. However, there was no significant difference between the preparations or the concentration of active ingredient in terms of their reduction of Heterobasidion infection. Mechanical treatment with incomplete coverage failed to control infection. Therefore, in conditions of moderate Heterobasidion spore load in the environment there seems to be no reason to use higher concentrations of P. gigantea in the treatment of spruce stumps.  相似文献   

9.
以野生唐古特白刺的茎段、叶片为外植体,研究了NaClO对外植体的消毒效果和激素2,4-D、NAA和6-BA对愈伤组织诱导及愈伤组织形态的影响,并利用疏松型愈伤组织建立了白刺悬浮细胞系,对其生长特征进行了分析。结果表明:对茎段和叶片用2%的NaClO消毒10 min最适宜,时间过长或过短均会影响成活率;3种激素对愈伤组织的相对生长量和形态均有影响,其中,2,4-D是主要影响因子,且茎段诱导出的愈伤组织相对生长量比叶片的高;根据愈伤组织的生长速度和形态,适宜用浅黄色疏松型愈伤组织构建唐古特白刺悬浮细胞系,最佳试验组合为MS+2,4-D 1.5 mg·L-1+NAA 0.2 mg·L-1+6-BA 0.4 mg·L-1,最佳继代接种量为7.5 mL母液,生长曲线呈"S"型,培养第7天细胞分裂指数达最大值(5.1%),培养第3天细胞活力最强(吸光值为0.69),存活率在细胞生长延迟期和稳定期较对数期下降略快,但均保持在84% 93%间。  相似文献   

10.
The chromium adsorption ability of leaves from 34 conifer species were examined. Among them, deciduous conifer species, such asLarix, Ginkgo, Metasequia, andTaxodium, showed high ability to adsorb chromium ions. Factors affecting chromium adsorption were studied using larch (Larix leptolepis) leaves to determine the optimum adsorption conditions. The factors included solution pH, contact time, temperature, and the initial concentration of chromium ions. Maximum adsorption for Cr3+ was observed at pH 5, and maximum Cr6+ adsorption occurred at pH 3. The amount of Cr6+ adsorbed on the adsorbent increased rapidly during the first 4 h, then gradually increased, and finally reached equilibrium in 16 h. The adsorption rate of Cr3+ was somewhat slower than that of Cr6+. The adsorption isotherm for Cr6+ adsorption was composed of two straight lines, suggesting that the adsorbent could not practically reduce the concentration of Cr6+ in solution below 1.6 mg Cr/L Column experiments using larch leaf packing suggested that the practical operation could be controlled by monitoring the effluent pH.  相似文献   

11.
In vitro germination of conidia of Cylindrocladium quinqueseptatum Boedijn & Reitsma, a cause of leaf blight of Eucalyptus spp., began after 4.5 h of incubation and attained approx. 95 % within 8 h; germination was optimal at 25°C. Conidial germination on the intact leaves of 2-month-old E. grandis occurred after 3 h of incubation. Formation of appressorium over the epidermal cells was recorded first on the abaxial surface of leaves at 6 h and later on the adaxial surface. Formation of appressorium over the stomata was found only very rarely and most leaf penetrations occurred directly through epidermal cells.  相似文献   

12.
A field study was conducted for six years (1981–1986) on sandy loam soil on intercropping hedgerows of Leucaena leucocephala (Lam) de Wit. with three field crops viz. maize (Zea mays L), black gram (Vigna mungo L) and cluster bean (Cyamopsis tetragonoloba L Taub.). In treatments 1 and 2 Leucaena hedges were planted as pure crops at close (25 cm × 75 cm) and wide (25 cm × 375 cm) spacings. In treatments 3, 4 and 5 the three field crops were intercropped between the hedgerows of Leucaena at the wide spacing, and in treatments 6, 7 and 8 the field crops were raised as pure crops. Leucaena was topped to 75 cm each time it attained a height of 175 cm. The pure crop of Leucaena at close spacing produced an average, over the six years, of 34 t ha−1a−1 of green fodder and 9.4 t ha−1a−1 of air dry fuelwood. The Leucaena at wide spacing produced 18.9 t ha−1a−1 of green fodder and 6.3 t ha−1a−1 of fuelwood. Intercropping with field crops decreased the yield of green fodder and fuelwood. The yield of all the field crops was less when raised as intercrops than as pure crops. Mean maximum net returns were obtained from intercrops of Leucaena and cluster bean (Rs 3540 ha−1a−1) which were significantly higher than the returns from pure crop of Leucaena at wide spacing but similar to the returns from pure crops of cluster bean. Leucaena with maize (Rs 3273 ha−1a−1) and black gram (Rs 3125 ha−1a−1) gave significantly higher net returns over pure crops of Leucaena at wide spacing, maize and black gram. ICRISAT = International Crops Research Institute for the Semi-Arid Tropics- Hyderabad, India. CIAT = Centro International de Agricultura Tropical - Cali - Columbia  相似文献   

13.
树脂吸附法分离高纯茶多酚新工艺研究   总被引:4,自引:1,他引:4  
研究了树脂吸附法分离纯化茶多酚的绿色工艺。浸提低品位茶叶得到的浸提液,乘热粗沙沙滤,调pH值至1.5,使色素、咖啡因和大分子物质得到预分离,然后细沙沙滤、上AB-8树脂进行吸附,依次用蒸馏水和pH值为2-4的5%的乙醇溶液洗脱处理,洗脱剂为质量分数60%的乙醇,洗脱液喷雾干燥得到茶多酚产品,纯度可达90.22%。  相似文献   

14.
In a laboratory screening of 12 isolates of entomopathogenic fungi against nymphs of the mulberry whitefly (Pealius mori Takahashi), Beauveria bassiana (Balsamo-Crivelli) Vuillemin CKB-048 was the most virulent, causing 87 ± 3% mortality at 1 × 106 conidia/ml. Infection was confirmed by growth of the fungus from cadavers and by scanning electron microscopy of treated nymphs. Beauveria bassiana CKB-048 was formulated as a wettable powder (1 × 109 conidia/g) and tested in two mulberry (Morus alba Linn) plantations in central and northeastern Thailand. In both locations, two spray applications of B. bassiana CKB-048 at 3.75 × 1012 to 6.25 × 1012 conidia/ha and at 14 day intervals provided good control of whitefly nymphs; control with B. bassiana CKB-048 was comparable to that with the pesticide buprofezin at 250 g of active ingredient/ha. In addition, no mortality of silkworm larvae occurred when the larvae were fed with mulberry leaves sprayed with B. bassiana CKB-048 7, 14, or 21 days earlier.  相似文献   

15.
银杏大蚕蛾的生物学和防治技术研究   总被引:6,自引:0,他引:6       下载免费PDF全文
银杏大蚕蛾在湖北一年发生一代。幼虫5龄;4、5龄幼虫有绿色型和黑色型。幼虫取食38种植物,天敌有53种。本文还叙述了该虫发生与环境的关系。防治试验表明:喷洒2.5%溴氰菊酯5000倍液、2×10~8孢子/ml白僵菌液、25%苏脲一号500倍液、1×10~8PIB/mlDjNPV虫尸液效果均很好。  相似文献   

16.
Pathogenicity of Lecanicillium muscarium, against Eretmocerus sp. nr. furuhashii (Hymenoptera: Aphelinidae), was investigated under laboratory conditions to determine if the fungal infection of the whitefly host can effect the survival, longevity and fecundity of female parasitoid. The results indicated that the number of parasitized larvae surviving a L. muscarium treatment after 6 days of oviposition decreased with increasing concentrations of L. muscarium and in later stages of development (12 days post oviposition) were not affected by fungal application. There were no significant differences on adult parasitoid survivorship after 7 days among all treatments. Maximum survivorship (73.33%) was observed for control and it was minimum (60%) at 1 × 108 conidia/ml. L. muscarium showed a non significant effect on longevity and next offsprings of female parasitoids. The percentage emergence of parasitoids from the whitefly nymphs produced by the females emerged from treated pupae was almost similar. Maximum emergence (69.77%) was observed at 1 × 106 conidia/ml and it was lowest (61.02%) at conidial concentration of 1 × 108 conidia/ml. Maximum longevity of adult Eretmocerus sp. emerging from whitefly nymphs when treated after 12 days of postoviposition was observed for 1 × 105 conidia/ml having a mean value of 5 days whereas the lowest longevity was 4.9 days observed at 1 × 108 conidia/ml. The results mentioned above indicate that the interaction among biocontrol agents is positive to a greater extent with minimum risk hazards.  相似文献   

17.
A new cyclohexanone glucoside (II) and a known cyclohexenone glucoside roseoside [I, (6S, 9S)-6-hydroxy-6-(9--D-glucopyranosyloxy-trans-7-butenyl)-1,5,5-trimethyl-1-cyclohexenone] were isolated from an ethanol extract of shirakamba (Betula platyphylla Sukatchev var.japonica Hara) leaves. The structure ofII was determined to be (6S, 9R)-6-hydroxy-6-(9-O--D-glucopyranosyloxy-trans-7-butenyl)-1, 5,5-trimethyl-1-cyclohexanone by1H-NMR and13C-NMR spectroscopic analyses. It was named dihydroroseoside.  相似文献   

18.
An improved method for selection of large electro-fused protoplasts ofPopulus alba by a micromanipulator was developed. The conditions for electric cell fusion treatment were optimized. For the best result, protoplasts with a cell density of 5 × 105/mL were treated with an alternate current (1 MHz, 200 V/cm) and pulsed with a direct current (2 kV/cm) for 100μs in 2.5 mM CaCl2 and 0.55 M mannitol. The electo-fused protoplasts were cultured in NH4NO3-free Murashige and Skoog’s medium containing 0.6 M of mannitol, 0.09 M sucrose, 1μM of 2,4-dichlorophenoxyacetic acid and 0.1μM of benzyladenine, the same medium used for protoplast culture, but at a very low cell density of 5–10 × 102/mL in a well of a 96-well culture plate. When cell aggregates derived from individual fused protoplasts were transferred to fresh medium with 0, 0.3 or 0.6 M mannitol, large colonies developed. In the shoot differentiation medium, the reaction of the calluses derived from large fused protoplasts towards the growth regulators differed from the non-fused ones. In medium containing 1μM each of naphthalene acetic acid andN-(2-chloro-4-pyridyl)-N′-phenylurea, growth of callus from electro-fused ones was not reduced by much compared to the control, but shoot differentiation was inhibited. Gibberellic acid (0.1–10μM) was beneficial to shoot regeneration; however, irregularly shaped leaves appeared at high gibberellic acid concentrations. Shoots regenerated were rooted in Murashige and Skoog’s medium containing 4μM of indole-3-butyric acid. Some plantlets obtained had a varied morphology. Based on the characteristics of growth, some cells derived from electro-fused protoplasts appear to be physiologically different from the non-fused one.  相似文献   

19.
Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > TithoniaEuphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

20.
Sugi (Cryptomeria japonica D. Don) is one of the most important planted trees in Taiwan. The normal heartwood of sugi has a red to pinkish rose color. Unfortunately, this pleasant appearance is susceptible to discoloration after environmental exposures. This discoloration is a serious defect that decreases the value of sugi products. The objective of this study was to investigate the effects of environmental factors such as moisture, oxygen, and lights of different wavelengths on the discoloration of sugi. The results show that under the combined effects of light and oxygen the color of heartwood changes from red (or rosepink) to bluish green. The color further darkens and eventually turns to black with the presence of moisture. As for the effect of light wavelengths on the discoloration of sugi heartwood, it was found that the red color was enhanced after being irradiated with light of wavelengths above 600 nm. Botha * andb * values increased significantly as a result of such exposure.  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