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991.
干旱胁迫对白桦实生幼苗叶片蛋白质的影响   总被引:9,自引:0,他引:9  
The studies on leave protein of Betula platyphylla seedlings by the methods of SDS-PAGE electrophoresis and dimensional gel electrophoresis was concerned. The result indicated that some new proteins such as 29kD pI4.3, 29kD pI4.2, 14kD pI5.3 and 11.5kD pI5.16 protein point were induced by soil drought stress, and some protein disappeared,for instance four protein between 12.4 - 11.5kD pI5.8 - 6.44 in seedlings leaves of B. platyphylla during soil drought stress.  相似文献   
992.
在全面调查普洱市七叶莲野生资源地理分布基础上,采用主成分分析法研究七叶莲野生资源地理分布与气候、地形之间的关系,并对海拔与七叶莲枝叶总皂甙含量做相关性分析。调查结果表明:七叶莲野生资源在普洱全市均有分布,在喀斯特地貌区域分布尤为集中,其水平分布范围为99°20′11″E~101°55′04″E,22°18′20″N~24°17′58″N,垂直分布范围为海拔500~1900 m。经主成分分析表明,影响七叶莲地理分布的主要水热指标的排序为湿度因子>热量因子>降水因子;相关分析结果表明,七叶莲所分布的海拔与其林木枝叶总皂甙的含量具负相关关系,其相关系数为-0.948,最高海拔(1460 m)与最低海拔(1006 m)的七叶莲枝叶总皂甙含量比为1.0∶1.5。  相似文献   
993.
三种薇菜产品营养成分的分析与比较   总被引:2,自引:1,他引:2  
以南薇菜干、北薇菜干、水煮薇菜为原料,对它们的水分、灰分、粗蛋白、粗纤维、粗脂肪、胡萝卜素、Vc、K、Na、Ca、Mg、Fe、Cu、Se等营养成分进行了分析。结果表明:水煮薇菜含水量最高达到85.7%,两种薇菜干的水分含量差异不显著,但与水煮薇菜水分含量有极显著差异。南北薇菜干灰分和K含量差异显著,水煮薇菜含量最低与两种菜干均有极显著差异;水煮薇菜的粗脂肪和胡萝卜素含量最低与南薇菜干都有极显著差异,南北薇菜干间只有粗脂肪含量差异显著。三种菜样间Ca含量都有极显著差异,但Fe含量差异都不显著。粗蛋白、粗纤维、Vc、Na、Mg、Se、Cu南北薇菜干间无显著差异,水煮薇菜含量最低与两种菜干都有极显著差异。  相似文献   
994.
This paper took the upper-lower wide belt sander B229 with four-feet wide belts, manufactured in China, as the study target. By means of framework dynamic design, we study its vibration characteristics by commencing from the place having horizontal defects and used experimental modal analysis (EMA) and power spectrum density (PSD) to observe the sanding parts and the whole machine, respectively. In the modal test, we mainly adopted the cross spots testing method to get the frequency response function of the fixed spots to every excitation vibration spot, then applied the SISO frequency response function and the frequency response function fitting method to identify and complete parameter recognition, respectively. The typical frequency response function chart of the whole machine and its sanding parts, as well as its second-order mode charts of contacting roller, were obtained. Through PSD analysis, we can get the amplitude-frequency spectrum and drive frequency. Translated from Scientia Silvae Sinicae, 2005, 41(6): 132–137 [译自: 林业科学]  相似文献   
995.
The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)3] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)3 was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)3 was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281  相似文献   
996.
In order to study the influence of wood microstructure on wood dyeing, eleven parameters of wood microstructure and 5 parameters of wood dyeing effects for 34 pieces of wood boards from 5 trees of Chinese white poplar (Populus tomentosa) were determined and the multiple regression analysis between the factors of wood microstructures and the parameters of wood dyeing effects were made. The regression results show that each variable of wood dyeing effects has higher relationship with wood microstructures, and multiple correlation coefficients between each variable of wood dyeing effects and wood microstructures are 0.483 6~0.799 8. The main factors of wood microstructures influencing wood dyeing of Chinese white poplar are proportion of wood ray, proportion of vessel and proportion of wood fiber according to comparing the standardized regression coefficients of multiple regression equation.  相似文献   
997.
Isik  Fikret  Toplu  Ferit 《New Forests》2004,27(2):175-187
Natural black poplar (Populus nigra L.) clones sampled from river courses were tested in the arid southeast region of Turkey, using a randomized complete block field design with four replications. Clones were laid out in row plots of eight ramets each. Height and apical dominance were assessed at age one year; diameter, survival, bole straightness and branchiness were measured at age two years. Clones differed significantly in survival, growth and quality traits. The results showed that promising clones exist in natural populations. Two commercial clones out of four did not grow as fast as the top new selection clones. For bole straightness, three commercial clones had significantly lower grading scores than the top best 14 clones. Principal components analysis indicated that growth, apical dominance and branching are the most important traits distinguishing black poplar clones. Diameter had a moderate correlation (0.34) with bole straightness. Relationships between geographic variables (elevation, latitude and longitude) with growth and stem quality traits were weak. Considerable genetic variation was observed among clones for all the traits. Genetic differences among the clones accounted for 27% (survival, bole straightness) to 39% (height) of the total variance. Broad-sense individual heritability ranged from 0.27 (survival) to 0.37 (apical dominance). Clonal mean heritabilities were higher than individual heritabilities and ranged from 0.60 (survival) to 0.82 (diameter), implying considerable gain could be realized via selective improvement methods.  相似文献   
998.
Salix discolor Mühl. (Sd) and Salix viminalis L. (Sv) were planted under short-rotation intensive culture (SRIC) on three unirrigated abandoned farmland sites with different drainage conditions, one well-drained (S1) and the other two poorly-drained (S2, S3). One dose of dried and granulated sludge equivalent to 150 (T1) kg of “available” N ha−1 was applied to some plots in the spring of the second season while others were left unfertilized (T0). The aims of the experiment were (i) to investigate plant response (growth and productivity) to plantation site conditions and sludge application; (ii) study nutrient status by foliar analysis. Over three seasons, growth in height and aboveground biomass were greater for S. viminalis than for S. discolor on all sites. S. viminalis planted on poorly-drained site 2 had the highest biomass yield (45.28 t ha−1). Both species showed best height and diameter growth on poorly-drained sites. For both species, best performances were obtained on wastewater sludge fertilized plots. Comparative foliar analysis suggested that unfertilized sandy soil (S1) and low foliar nitrogen concentration and content were limiting factors in the performance of the two species. Soil nitrate concentration increased as a result of sludge application. Heavy metal accumulation from sludge does not represent a risk to the environment. It was concluded that S. viminalis had the best productivity on clay sites, and that a moderate dose of dried and pelleted sludge (150 kg of “available” N ha−1) may be a good fertilizer during the establishment of willows in SRIC, and may reduce nitrate leaching.  相似文献   
999.
苏云金杆菌杀虫晶体蛋白基因转化美洲黑杨的研究   总被引:46,自引:3,他引:46  
陈颖  田颖川 《林业科学》1995,31(2):97-103
本研究首先建立了美洲黑杨叶片外植体的再生系统,并利用Horsch等人1985年发明的叶盘法,将分别带有嵌合基因NPTII和1.8kb或2.1kb Bt.基因的土壤杆菌LBA4404与美洲黑杨叶片共培养。采用30mg/l和50mg/l两种浓度的卡那霉素筛选转子,约28天左右的时间,有不定芽从外植体切口处形成。两种卡那霉素浓度下共形成275个伸长芽,存活了187株。这187株分别进入卡那霉素30mg/  相似文献   
1000.
Financial appraisal of agroforestry is not different in kind from appraisals applied to pure forestry. Existing techniques for valuing non-market effects may also be applied. Effects on hydrological and carbon fluxes might be less favourable than those of pure forests. In the confusing field of biodiversity valuation too, only limited and specific claims can be made for agroforestry. Amenity valuation techniques developed for trees and woodlands encounter additional problems of interpretation in an agroforestry context. Agroforestry may offer a quantifiable value in short-term sustainability, and might meet recent economic definitions of long-term sustainable development, without encountering the full dangers to future generations embodied in conversion of natural to human capital.  相似文献   
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