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为实现杜仲叶中生物活性成分和杜仲胶的高效提取分离,采用连续热水浸提、碱提取、酶水解和石油醚提取杜仲叶,分别得到了杜仲精粉、杜仲多糖(水溶性多糖和碱提多糖)及杜仲胶。考察了料液比和温度对活性成分提取得率的影响,探讨了酶解时间和酶种类对杜仲叶残渣水解的影响,最后对杜仲精粉、水溶性多糖和碱提多糖的铁离子还原能力和DPPH自由基(DPPH·)清除活性进行了测定,并对杜仲胶相对分子质量进行了测定。研究结果表明:料液比为1∶10(g∶mL),温度为80℃时,总黄酮和绿原酸的提取得率最大分别为50.08和6.83 mg/g。杜仲水溶性多糖、碱提多糖、杜仲精粉均具有较好的抗氧化能力,其中杜仲精粉抗氧化活性最高, 5 g/L时杜仲精粉的铁离子还原能力为4.01 mmol/L, 300 mg/L时DPPH·的清除率为94.46%,与Vc相当。杜仲叶水提残渣酶解48 h时,葡聚糖和木聚糖水解率最大,分别为86.77%和15.62%。杜仲叶中水溶性多糖的得率为13.2%,杜仲胶得率为1.86%,碱提多糖得率为9.8%,杜仲精粉得率为8.0%。杜仲胶的M_w和M_n分别为330 398和84 526,远大于水溶性多糖和碱提多糖的相对分子质量,但相对分子质量分布指数为3.91,分散程度明显低于杜仲多糖。 相似文献
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4种木质纤维素预处理方法的比较 总被引：3，自引：0，他引：3
采用4种方法对玉米秸秆预处理,研究了不同预处理方法对酶水解性能和可发酵性糖得率的影响,分析了预处理物料主要成分,预水解液中糖组成、碳水化合物降解产物及木质素降解产物含量.100 g玉米秸秆经稀酸、稀酸磨浆、中性蒸汽爆破和稀酸蒸汽爆破预处理、洗涤后,物料中纤维素由37.17g分别降为33.96、33.54、32.63和32.88 g,木聚糖由22.84 g分别降为2.77、2.47、3.56和2.05 g,木质素由18.76 g分别降为17.63、17.42、16.90和17.25 g.稀酸蒸汽爆破预处理物料在底物质量浓度100 g/L、纤维素酶用量20 FPIU/g(以纤维素计,下同)、β-葡萄糖苷酶用量3 IU/g下酶水解48 h,纤维素水解得率为75.91％.玉米秸秆经稀酸蒸汽爆破预处理、纤维素酶水解后可发酵性糖得率为44.93％(以玉米秸秆为基准). 相似文献
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以锯木屑为原料,采用蒸汽爆破进行预处理,然后酸催化提取糠醛.探讨了预处理温度、爆破压力、预处理时间及液料比等因素对糠醛得率的影响.采用响应面法建立二次回归模型,并对预处理工艺进行了优化.研究结果表明:预处理能有效的促进锯木屑的降解,提高糠醛的得率.在预处理温度为216℃、爆破压力1.8 MPa、预处理时间6min、液料比3∶1(mL∶g)时,糠醛的得率(79.13％)比相同条件下未进行蒸汽爆破预处理的试样(55.35％)提高了23.78个百分点. 相似文献
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超临界二氧化碳萃取杜仲果实中桃叶珊瑚苷工艺研究 总被引：3，自引：2，他引：1
采用超临界CO2流体萃取技术选择适合的夹带剂,进行了从杜仲果实中提取桃叶珊瑚苷的工艺研究.运用L16(45)正交表,较系统地探讨了各因素对提取效果的影响,提取液以Epstahl试剂显色用分光光度法进行分析.研究表明:与传统的溶剂提取法相比,超临界CO2萃取法具有操作简单、活性成分保存好、后续分离易于进行等特点;在萃取中以75 %的乙醇为夹带剂,当萃取压力26 MPa、萃取温度55 ℃、分离温度30 ℃、萃取时间120 min、夹带剂用量与原料比6∶1(mL∶g)的条件下,效果最佳,桃叶珊蝴苷得率1.921 %. 相似文献
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This study investigated the dynamic modulus of elasticity (DMOE) of wood panels of Fraxinus mandshurica, Pinus koraiensis, and Juglans mandshurica using the natural frequency measurement system of fast Fourier transform (FFT). The results were compared with the static
modulus of elasticity (E
S) tested by a mechanical test machine. The results show a significant correlation between E
S, transverse vibration DMOE (E
F), and longitudinal vibration DMOE (E
L). For all of these species, the correlation between E
S, E
F and E
L is more significant than the individual species, which indicated that the FFT method is universal. The correlations between
E
S and sample’s density (ρ) are significant, but the correlation coefficient of E
S and ρ is lower than those between E
F, E
L and E
S. The E
S of wood is more accurately tested by the analysis based on FFT measurement than by the estimation based on density.
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Translated from Scientia Silvae Sinicae, 2005, 41(6): 126–131 [译自: 林业科学, 2005, 41(6): 126–131] 相似文献
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落叶松水浸液对胡桃楸幼苗生长的影响 总被引：3，自引：0，他引：3
YANG Li-xue 《林业研究》2005,16(4):285-288
A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations （100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1） were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species. 相似文献
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Wu Xingyin Zhang JinghuaForest Pest Control Quarantine Station of Archeng City of Heilongjiang ProvinceXiang Cunti Li Guisheng '''' Shao Zhongwen Liu Xiaoguang Ma LiyaNortheast Forestry UniversityZhang Xianwen Li Zhuo Xie Guicai Dang WenqiangArcheng Forestry Bureau of Heilongjiang Province 《林业研究》1991,2(2):7-16
The poplar bacterial canker caused by Erwinia sp is a serious disease spreading inmost parts of Northeast China,where poplars are cultivalted.The disease seriously infects thosepoplars belonging to section Aigeiros or the intersection hybrids of section Tacamahaca and section Aigeiros and their clones.Five fine poplar cultivars resistant to the bacterial canker have been ob-tained by screening tests.They are Lz_2(Populus simonii×nigra var.italica),A_(15)(P.×sp.)613(P.×sp.),A_(102)and A_(98)(P.simonii×sp.)T following chemicals are obviously effective,such as:50％DT germicide ,40％ XF-136 and 10％ C.C.M.A.or 12.5％ ramphencol and 50,000 ppm/mlvalidamycin,with which the stems or roots can be watered. 相似文献
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利用PCR－RFLP鉴定体系和SDS－PAGE表达蛋白的分析方法，分析了来自我国不同森林立地带（寒温带，中温带，暖温带，北亚热带，中亚热带，南亚热带，高原亚热带，热带）自然保护区森林土壤中分离的72株苏云金芽孢杆菌的cry 1，cry 2，cry 3，cry 4，cry 5，cry 8，cry 9，cry 10，cry 11，cry 1I杀虫晶体蛋白基因类型，表达蛋白和杀虫活性的生物测定。研究表明：同时含有cry 1，cry 2，cry 1I3类 有21株菌，6株菌含有cry 1，cry 2类基因，4株菌含有cry 1和cry 1I基因，只含有cry 1基因的1株，cry 2基因的4株，36株菌不含所鉴定的10类基因。同时证明：绝大多数含有cry1基因的菌株表达了130kD蛋白，含有cry2基因的菌株表达了60kD的蛋白。对不同农，林害虫棉铃虫，杨扇舟蛾，舞毒蛾，马尾松毛虫，黄粉甲，榆兰叶甲，落叶松叶蜂等幼虫的杀虫活性进行了生物测定。进一步证明了苏云金芽孢杆菌cry基因，表达蛋白及杀虫活性三者的相关性。为生产和科研提供了生物治虫，抗虫育种的苏云金芽孢杆菌cry基因资源。 相似文献
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In sahelian countries, parklands are very important for human populations from an economic point of view. Unfortunately, they are currently being threatened by pests such as Loranthaceae which are stem parasites. In Burkina Faso, six species of Loranthaceae have been identified and located geographically: Agelanthus dodoneifolius (DC.) Polh. & Wiens, Englerina leucardii (Engl.) Balle, Globimetula cupulata (DC.) Van Tieghem, Tapinanthus bangwensis (Engl. & K. Krause) Danser, T. globiferus (A. Rich.) Van Tieghem and T. ophiodes (Sprague) Danser. Agelanthus dodoneifolius is by far the most widespread in the country whereas Globimetula cupulata is strictly located in the southeast. A list of their hosts has been established showing: 154 species dispatched in 96 genera and 42 families. Among them, the most frequently parasitized families are the Caesalpiniaceae, the Combretaceae and the Mimosaceae. A biological cycle scheme showing the main phenological stages common to the six Loranthaceae observed in Burkina Faso is reported. Based on a review of the damage caused by Loranthaceae, pruning, chemical treatments, genetic selection of resistant individuals and biological control are suggested as possible control methods.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Four regions of chloroplast DNA were sequenced as a prospective genetic marker to identify Japanese representatives of Cyclobalanopsis: Quercus acuta, Q. sessilifolia, Q. salicina, Q. myrsinaefolia, Q. glauca, and Q. gilva. We found that Q. gilva was distinguished from other species based on both the trnL-trnF and trnT-trnL intergenic spacers. The evidence shows good coincidence with the fact that Q. gilva has several peculiar morphological features distinguishable from those of other species. There was no difference in trnL intron and matK. Both trnT-trnL and trnL-trnF intergenic spacers are capable of being used as genetic markers to identify Q. gilva among Cyclobalanopsis species.Part of this paper was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 3–5, 1998 相似文献
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Floristic composition and soil characteristics of tropical freshwater forested wetlands of Veracruz on the coastal plain of the Gulf of Mexico 总被引：1，自引：0，他引：1
We studied the influence of geomorphological setting and soil properties on the vegetation structure, composition and diversity of five forested coastal wetlands in Veracruz on the Gulf of Mexico. These swamps are located on floodplains and in dune depressions. We recorded 109 woody and herbaceous species. The most frequent species were the trees Pachira aquatica, Annona glabra, Diospyros digyna and Ficus insipida subsp. insipida, the lianas Dalbergia brownei and Hippocratea celastroides and the hemi-epiphyte Syngonium podophyllum. The Shannon-H diversity index varied from 2.659 to 3.373, density from 1750 to 2289 stems ha−1 and basal area from 32.7 to 76.42 m2 ha−1. The classification analysis defined two groups: one corresponded to forested wetlands along the floodplain (Apompal, Cienaga, Chica) and the other included Mancha and Salado, in dune depressions. PCA ordination of soil parameters during the rainy season explained 67.0% and during the dry season 69.1% of the total variance. In the rainy season Mancha and Salado samples remain close together because they have lower Mg, Na, K, % Total C and % Total N values. Apompal and Chica samples remain close to each other because of their high levels of % Total C, % Total N, Mg, Na and high soil water content. Cienaga samples are separated from the others because of high values of P, Ca and Eh as well as high water levels. In general, soil parameter ordination during the dry season showed that redox potential, P, water level and water content decreased in the forested wetlands and Na values increased in Chica. The soil textures identified were clay, sandy clay loam, sandy loam and clay loam; clay texture dominated alluvial processes in the floodplain (e.g., Cienaga). The forested wetlands in the floodplains had similar vegetation and the same happened in the dune depressions but soil characteristics were more variable in both cases. Plant diversity in floodplains tends to be relatively high, and the presence of adjacent tropical forests probably increases its richness, except in cases in which there are stressing factors, such as salinity. The forested wetlands studied showed dominant floristic elements, which extend north into Florida such as A. glabra and Ficus aurea. Other dominant elements such as P. aquatica are also found in Central and South America. The forested wetlands studied are subjected to continuous deforestation to transform the land into farming or ranching activities, this being a common practice throughout the distribution range of these forests. 相似文献
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Shirugumbi Hanamanthagouda Manohar Poornananda Madhava Naik Nagella Praveen Hosakatte Niranjana Murthy 《林业研究》2009,20(3):268-270
The gymnemic acid contents in various organs of Gymnema sylvestre were investigated by High Performance Liquid Chromatography (HPLC) method. The results shows that the content of gymnemic
acid in various organs, obviously different, was 54.29, 31.66, 28.82, 27.67, 25.39, 20.56 and 1.31 mg·g−1 DW in shoot tips, flowers, nodes, leaves, internodes, roots and seeds, respectively. The highest gymnemic acid content (54.29
mg·g−1 DW) was found in shoot tip, 1.96 fold higher than that in leaves (27.67 mg·g−1 DW). Maximum quantity of gymnemic acid (35.39 mg·g−1 DW) was observed in the young leaves, which was 1.52 times higher than that in old leaves (23.07 mg·g−1 DW). The content of gymnemic acid in young, middle and old internodes was 26.47, 25.77 and 23.94 mg·g−1 DW, respectively, all lower than that in leaves (27.67 mg·g−1 DW), whereas the content of gymnemic acid in young, middle and old nodes was 27.96, 28.81 and 29.66 mg·g−1 DW, respectively, all higher than that in leaves. The study provides the scientific evidences for the rational development
and utilization of Gymnema sylvestre resources, since over exploitation of natural stands has caused depletion of these plants in nature.
Foundation project: This work was supported by University Grants Commission, New Delhi (No. 33-88/2007 (SR)) 相似文献