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971.
洪雅县退耕竹林碳储量时空格局 总被引:2,自引:0,他引:2
建立退耕还林重点示范县洪雅县竹林碳储量多元线性回归遥感模型,基于碳储量遥感模型估算出四川省洪雅县退耕还林以前(1994年)、退耕还林后第4年(2004年)和退耕还林后第7年(2007年)的竹林碳储量,利用地理信息系统软件对竹林碳储量的时空格局变化进行定量分析。结果表明:13年间(1994—2007年)洪雅县竹林碳储量和面积均呈现逐年上升趋势,前期(1994—2004年)增速大于后期(2004—2007年);竹林碳储量和面积分布规律相似,都呈现出向低海拔、平缓坡和各坡向发展的趋势,其中2004年>25°坡度区域竹林碳储量和面积变化最明显,2004年>25°坡度区域竹林碳储量增加量占总增加量的79.53%,竹林面积增加量占总增加量的78.18%,表明退耕还林工程的实施是区域竹林碳储量与面积增加的驱动力;竹林碳密度呈现先降后升总体略微降低的特点,1994年碳密度最高为33.76tC·hm-2,2004年下降为33.25tC·hm-2,2007年又恢复到33.67tC·hm-2;利用克里金插值(Kriging)对模型进行优化可在一定程度上提高预测精度。 相似文献
972.
973.
Quercetin-3-O-β-D-glucuronide, isolated from Polygonum perfoliatum L., was evaluated by antiviral efficacy against influenza A virus and anti-inflammatory activity in vivo in mouse, and it was used for quality evaluation of P. perfoliatum L.. In vivo study, oral administration of quercetin-3-O-β-D-glucuronide significantly suppressed ear edema induced by dimethyl benzene and peritoneal permeability induced by acetic acid in mice, and quercetin-3-O-β-D-glucuronide also showed to possess inhibitory activity against influenza A virus (FLUAV). In the present study, additionally, a rapid, simple and sensitive method for quantitative analysis of quercetin-3-O-β-D-glucuronide in P. perfoliatum L. was developed using high performance liquid chromatography (HPLC) coupled with photodiode array detection. The separation was carried out on a Lichrosher-C18 column (250 mm × 4.6 mm, 5 μm) together with a C18 guard column at isocratic elution systems of methanol (A) and 0.05% aqueous phosphoric acid (B) (43:57, v/v) with detection wavelength at 258 nm and column temperature at 30 °C. The method was validated for linearity, repeatability, limit of quantification (LOQ), precision and robustness. The contents of quercetin-3-O-β-D-glucuronide in 28 samples from different regions of China were between 0.06% and 2.09%. The developed analytical method was applied to investigate P. perfoliatum L. and for quality control of the herb. 相似文献
974.
Wafo P Kamdem RS Ali Z Anjum S Begum A Oluyemisi OO Khan SN Ngadjui BT Etoa XF Choudhary MI 《Fitoterapia》2011,82(4):642-646
A new diterpenoid, 15-angeloyloxy-16,17-epoxy-19-kauronic acid (1), along with five known metabolites, 16-kauren-19-oic acid (2), 6′-hydroxy-2′,3′,4,4′-tetramethoxychalcone (3), isosakuranetin (4), acacetin (5), and kaempferide (6) was isolated from the organic extracts of the roots of Chromoleana odorata. Their structures were determined by spectroscopic evidences. The structures of 1 and 2 were further confirmed by single-crystal X-ray diffraction studies. Compound 2 exhibited significant α-glucosidase inhibitory and antibacterial activities against Escherichia coli and Bacillus subtilis. 相似文献
975.
The present study was aimed to investigate the possible interaction of the standardized extract of Acorus calamus (AC) with Cytochrome P450 enzyme, quantitative determination of the α-asarone in the AC rhizome was performed by RP-HPLC method. In vitro interaction of the plant extract was evaluated by CYP450-carbon monoxide complex (CYP450-CO) assay. Effect on individual isoforms such as CYP3A4 and CYP2D6 isozymes were analyzed through fluorescence product formation and respective IC50 values were determined. CYP450-CO assay showed moderate interaction potential. Extract showed higher IC50 values (46.84 ± 1.83-32.99 ± 2.21 μg/ml) comparing to the standard inhibitors and lower IC50 value than α-asarone (65.16 ± 2.37-42.15 ± 2.45 μg/ml). 相似文献
976.
César Pérez-CruzadoFernando Muñoz-Sáez Fernando BasurcoGuillermo Riesco Roque Rodríguez-Soalleiro 《Forest Ecology and Management》2011,262(6):1067-1077
Empirical, statistically based models were used to describe the growth and development of Eucalyptus nitens plantations for a range of site productivities and the standard biomass and pulp silvicultural regime currently applied in Northern Spain. The results obtained, along with data gathered from a network of 68 plots, 48 trees felled for biomass estimations and 73 trees sampled for foliar area estimation were used to parameterize the 3-PG model for this species in Northern Spain. Most parameters associated with allometric relationships and partitioning (i.e. bark and branch fraction, basic density, age modifier and mortality) were derived from local data, and the remaining parameters were obtained from published studies on E. nitens or default values previously used for E. globulus. The parameterized model was validated with data from three trials measured from age 3 years until age 8-14 years, and performed better than the empirical model in terms of total stand under bark volume, mean diameter at breast height, basal area and foliar biomass. The process-based model was then used to forecast changes in plantations subjected to a clearwood regime, initializing the model at age 3 years, considering 3 prunings, 2 thinnings and lengthening the rotation to 18 years. This integrated regime was able to provide biomass for bioenergy, pulp or fibreboard wood and also solid wood, with thinning operations assisting the financial viability, and was a potentially good alternative for productive sites. 相似文献
977.
新形势下林业制图既要图面整洁、美观大方,又要高效、简单,手工制图已不符合现代林业发展要求,正逐渐被淘汰。笔者对应用CorelDrawX3绘制林业工程作业设计图的方法和技巧,包括图框绘制、小班勾绘、着色、求积以及绘图成果打印等进行了详细介绍,容易掌握、色彩丰富、制图效率高。CorelDrawX3是绘制林业工程设计图的实用... 相似文献
978.
979.
CS3是CFA(产肠毒素型大肠杆菌引起腹泻时产生两类毒性因子之一)阳性株的保护性抗原。临床研究结果表明,以CS3作为疫苗可有效地防止由相关细菌导致的腹泻(董自正等, 相似文献
980.
太行山山前平原冬小麦生长季硝态氮的淋失研究 总被引:1,自引:0,他引:1
试验研究太行山山前平原冬小麦生长季NO3- N淋失结果表明 ,该区现有灌溉施肥制度冬小麦生长季存在NO3- N的淋失 ,且主要发生在底墒水和返青水灌溉时期。整个冬小麦生长季施N水平为 1 0 0kg hm2 、2 0 0kg hm2 和 4 0 0kg hm2 时 ,通过 1 80cm土层界面的NO3- N淋失量分别为 0 1kg hm2 、2 2 1kg hm2 和 1 1 0 1kg hm2 。 相似文献