多组分植被方向反射系数的解析计算模型

基于植被介质中的辐射传输理论和几何光学原理,提出了一个计算非随机、多组分植被多波段、多角度反射光谱的综合解析模型.此模型以作者以前建立的叶冠层模型和多组分模型为基础,通过对任意空间取向植被组分对冠层“热点”效应贡献的定量计算及在多次散射系数的估算中考虑冠层所有组分的作用,全面、深入地概括了植被冠层的多种组分以及它们的几何结构和光学性质的空间变化对植被多角度反射光谱的影响。模拟与实测结果的比较得出:模型基本上能抓住多组分植被反射光谱的角度分布特征,模拟出叶冠层模型所不能得到的自然植被方向反射系数和冠层“热点”效应的非对称性分布.模型的模拟结果表明,冠层“热点”效应在冠层组分的平均倾角约20°时达最大,然后随平均倾角的增大,“热点”效应明显减弱.     

油杉木材物理力学性质研究

对油杉Keteleeria fortunei木材的物理与力学性质进行测定与比较,结果表明,油杉木材的气干密度为0.576 g·cm~(-3),全干密度为0.544 g·cm~(-3),属中密度木材。油杉木材的气干径向、弦向和体积干缩系数分别为4.408%、3.272%和7.892%,气干差异干缩为1.347,油杉木材具有不易开裂和变形的特征。油杉木材的抗弯强度、顺纹抗压强度分别为92.701、57.217 Mpa,端面、弦面和径面硬度分别为4635.9、3420.8和3606.8 N,其抗弯强度、顺纹抗压强度和硬度均属中等。50年生油杉木材的物理力学性质优于22年生马尾松Pinus massoniana、湿地松Pinus elliottii和28年生杉木Cunninghamia lanceolata、秃杉Taiwania cryptomerioides。     

亮剑——蛋白质组学在中国

在“十一五”结束之年, 应《中国科学: 生命科学》编辑部邀请, 组织此次中国蛋白质组学专刊, 回顾我国蛋白质组学发展历程, 展示我国蛋白质组学最新成果, 同时为我国生命科学“十二五”的发展提供借鉴.

蛋白质组学是一门新兴但发展迅速的学科. 1994年, 蛋白质组概念的提出加速了蛋白质组学的凝聚和发展, 国际上主要发达国家和地区自此纷纷加大对蛋白质组学的支持力度, 蛋白质组学成为各强国科技角力新的“战场”; 至1997年, 国际蛋白质组研究已呈现蓬勃发展的势头. 我国在政府的大力支持下, 紧随其后, 较早开展了蛋白质组研究, 并迎头赶上. 过去的十余年间, 我国的蛋白质组学研究经历了最初的草创(仅少数几家单位的零星队伍), 到迅速发展、壮大, 继而走向世界, 并终于进入国际蛋白质组学研究领先行列的发展历程. ......     

香椿人工林和天然林木材纤维形态和化学成分比较研究

通过对香椿人工林和天然林木材纤维形态和化学成分的比较分析,揭示了香椿人工林木材纤维形态的特征及径向变化规律,以及人工林和天然林木材纤维形态和化学成分的差异。结果表明,香椿人工林的工艺成熟期为10年左右,其木材纤维长度和长宽比小于天然林,宽度大于天然林;纤维素、戊聚糖和木素含量均稍高于天然林;灰分和抽出物含量均低于天然林。香椿木材可作为林产工业纤维材料使用。     

17年生邓恩桉两个种源木材密度与干缩性研究

通过对邓恩桉两个种源木材基本密度和在湿、气、全干状态下的径、弦向尺寸的测定,研究了不同树干位置的基本密度和干缩率的变异规律,并运用加工工艺中减小木材皱缩和开裂措施(蒸汽调湿处理方法)探索皱缩开裂缺陷的恢复性能。结果表明:1)邓恩桉种源100(0.5265 g/cm³)的木材基本密度小于种源98(0.5360 g/cm³);2)木材基本密度在树干纵向呈波浪式变化,在横向边材显著大于心材;3)木材干缩率在纵向随高度的增加而减小,在横向边材大于心材,且弦向干缩率均为径向的1~3倍;4)经喷蒸调湿处理后,木材开裂程度减轻,且径向和弦向皱缩恢复率分别为0.4%、3.3%;5)木材基本密度与气干弦向干缩率存在极显著负相关(r=-0.313),并建立了气干干缩率与全干干缩率的回归模型。     

肿瘤新生血管及分子靶向治疗新策略

肿瘤血管靶向治疗是基于肿瘤新生血管与正常血管的不同,药物专一识别并阻断肿瘤新生血管,使肿瘤细胞“饿死”,而不影响正常细胞。从1971年Folkman提出“饿死肿瘤”的假说到2004年第一个血管靶向药物上市,记载着30多年领域发展的传奇经历。当今,肿瘤血管已成为生物医学和临床研究的热点,新的发现层出不穷。该文重点介绍肿瘤血管新靶点、新机制、新药物与未来发展。     

青海湖流域矮嵩草草甸土壤有机碳密度分布特征

通过对青海湖流域不同退化程度矮嵩草草甸土壤容重和有机碳含量的测定,确定了其土壤有机碳密度。结果表明:不同退化程度下矮嵩草草甸土壤有机碳含量和变化特征各有不同。从未退化-重度退化,0—100 cm土壤剖面平均有机碳含量分别为(25.17±4.73)g/kg,(17.51±3.06)g/kg,(20.79±1.30)g/kg和(14.53±1.20)g/kg,即未退化中度退化轻度退化重度退化;0—20 cm土壤平均有机碳含量从(64.47±11.70)g/kg减少为(14.52±1.52)g/kg,减少了77.48%。土壤剖面有机碳密度变化趋势与其有机碳含量变化趋势一致。0—100 cm土壤剖面有机碳密度分别为(18.16±4.12)kg/m3,(14.24±3.52)kg/m3,(18.64±2.82)kg/m3和(13.27±2.28)kg/m3,即中度退化未退化轻度退化重度退化;土壤有机碳集中分布在0—40 cm深度,从未退化到严重退化,该深度有机碳密度分别为(32.06±6.41)kg/m3,(25.10±4.20)kg/m3,(22.68±3.17)kg/m3和(17.10±2.77)kg/m3,比整个剖面有机碳密度高出76.53%,76.25%,21.68%和28.88%。不考虑其他因素,以空间尺度代替时间尺度,这一结果说明矮嵩草草甸的退化导致土壤逐渐释放有机碳,其作为储存碳的功能在减弱,必须加强对矮嵩草草甸生态系统的保护,以防止其碳库变为碳源。     

亚热带不同演替树种米槠和马尾松细根性状对比研究

选择福建省三明市中亚热带演替前期树种马尾松和演替后期树种米槠两种人工林为研究对象,采用土芯法研究两个树种细根(直径2mm)的生物量及其垂直分布、形态以及分支结构等细根性状特征。结果表明:(1)0—80cm土层米槠的细根生物量密度(0.21±0.06)kg/m3、根表面积密度(3.15±1.25)m2/m3和根长密度(2202.84±517.03)m/m3分别为马尾松的1.6、1.2倍和2.2倍,并且3个指标均随土层深度增加而降低,但演替前期树种马尾松细根在土层间分布更均匀,而演替后期树种米槠细根更富集于表层。(2)马尾松细根的直径(0.86±0.04)mm、比表面积(191±32)cm2/g分别是米槠的1.4倍和1.3倍;米槠细根的比根长(10.73±0.46)m/g、组织密度(0.49±0.06)g/cm3分别是马尾松的1.4倍和2.0倍,马尾松细根的较大直径和低组织密度的形态结构能够迅速生长占领土壤空间和适应干旱环境,而米槠细根的较小直径、高比根长和较高的组织密度使其具有较强养分竞争能力和应对取食压力;(3)米槠的比根尖密度(4288±63)个/g、比分叉密度(1164±155)个/g均为马尾松的2.2倍,米槠细根的高分支系统能够迅速利用富养斑块。结论表明处于不同演替阶段的树种细根性状具有明显差异,可能反映了不同的资源获取策略。     

陆地棉-野生比克氏棉杂种红花种质系的育成

采用种间杂交新技术,得到了陆地棉×野生比克氏棉的F_1不育株,在嫁接教养及短日凉爽条件下培育,雌雄恢复了低育性,通过3次回交及对早期剧烈分离世代的选择之后,首次育成了兼具双亲特征,即既有比克氏棉的红花紫花斑及细强纤维,又有陆地棉的株型、熟期、白绒、高衣分和结铃性的稳定的杂种选系,命名为“HB红花系”,这是一种前所未有的新型种质资源,具有新品种选育及遗传研究的重要价值.     

基因重组人白细胞介素-3在猴中的药代动力学

猕猴静脉注射¹²⁵Ⅰ标记基因重组人白细胞介素-3(30μg/kg)后RHPLC测定血浆浓度曲线,快速和末端半衰期分别为(0.15± 0.13)和(2.21± 0.59)h.皮下注射30,90和180μg/kg消除半衰期2.0～3.8 h,AUC基本上随皮下注射(SC)剂量而增大,CL_s相近 吸收受注射部位浓度限制.生物利用度0.71.药物在体内迅速降解.组织分布泌尿系统浓度最高,胆肠道、淋巴、骨髓和脾等与血浆相近,脑最低尿分析提示肾是降解器官之一     

Argentinean native wood species: Physical and mechanical characterization of some Prosopis species and Acacia aroma (Leguminosae; Mimosoideae)

One of the problems in marketing the wood of Prosopis and Acacia is the lack of standardization of its qualities. The aim of this paper was to obtain a preliminary detection of some properties of the wood of four species of the genus Prosopis and one species from Acacia grown in Argentina. To accomplish this objective, the content of extractives and some physical and mechanical characteristics were analyzed.The density ρ₁₂ of all the species indicates that these woods range from heavy to very heavy (?0.69 g/cm³). The total volumetric shrinkage values are low, less than 10%, for all species. The parallel compression strength and the shear strength for all the species indicate a very resistant wood (?46.93 MPa and ?18.35 MPa, respectively). Brinell hardness was higher than 5 kg/mm² in all cases. The species with less content of extractives is P. ruscifolia (approximately 9% of anhydrous mass) whereas A. aroma was the one with the greatest content (approximately 25% of anhydrous mass in the heartwood).     

杉木人工林木材力学性质与纤维形态关系的研究

应用正交试验设计方法对不同林龄、立地条件和林分密下杉木人林木材力学性质,纤维形态的测定结果为基础,采用多元线性回归方法,对杉木人工林木材力学性质与纤维形态的关系进行相关分析和回归分析,结果表明：杉木人工林木材顺纹抗压强度,抗弯强度等十一项力学性质指标与纤维长度,纤维宽度、壁厚、腔径、壁腔比之间存在极显著的相关关系。     

热带速生耐旱树种榆绿木的研究

榆绿木(Anogeissus acuminata var.lanceolata)在我国为一新纪录种,发现于云南省思茅县小橄榄坝为中心的狭窄河谷地带。本文对榆绿木的生态习性、生长特性和自然更新状况作了详细的分析,并对其材质和材性进行测定。榆绿木的气干容重为0.896 g/cm~3;顺纹抗压和抗弯强度之和高达1775 kg f/cm~2;静曲弹性模量203000 kg f/cm~2;冲击韧性达1.385kq f. m/Cm~2,是具有高强度、高韧性的工业用材。可作建筑、车辆、农具、体育运动器材及军工等用材。速生、耐旱,是一种有前途的干热河谷造林树种,还可作鞣料林和能源薪炭林栽培,具有很高的生态和经济价值。本文还对这一树种目前所面临的威胁作了分析,为合理开发利用及保护榆绿木森林资源提出了建议。     

人工林刨花楠木材主要特性的径向变异及其对气象因子的响应

为了给刨花楠材质预测、轮伐期选择及木材合理高效利用提供理论基础,本研究以17年生刨花楠人工林为对象,采用木材性质快速测定仪(SilviScan-3^TM)获得木材性质参数,研究人工林刨花楠解剖特性、木材密度与弹性模量的径向变异规律及其对气象因子的响应,重点分析生长轮宽度、年龄与各材性性质参数之间的相关性.结果表明: 刨花楠不同材性性状的径向变异规律不同,7～11生长轮为其变异曲线的转折点;木材密度和纤维壁腔比与生长轮宽度的相关性不显著,生长速度和生长轮年龄对大部分材性性状具有重要影响;不同气象因子对不同材性性状影响程度不尽相同,相对湿度是影响刨花楠材性的主要生态因子;各材性性状中,微纤丝角和弹性模量对气象因子的响应更敏感.     

Long-term Coordination of Timber Production and Consumption Using a Dynamic Material and Energy Flow Analysis

A dynamic model for wood and energy flows is used to analyze regional timber management. The model combines a sitequality-dependent forest-growth module with modules for the timber industry, timber products use, waste management, and energy supply. The model is calibrated with data of a Swiss lowland region for the period of 1900–1997. Scenarios are developed for the period until 2100 in order to discuss possible future roles of domestic timber.
Model simulations show that, with present strategies, timber overproduction will further increase in the twenty-first century because of an increase in forest site quality in the second half of the twentieth century, among other reasons. The increase in building gross floor area of the region by a factor of 5 during the twentieth century coincides with a reduction of timber use in building construction by a factor of 4.5, from 90 kg/m2 to 20 kg/m2. Increasing timber density in buildings could address overproduction; however, a strategy of timber construction could not be accomplished with domestic timber alone. A balance of production and consumption on the present level could also be achieved in a scenario in which the present building stock is gradually exchanged during the twenty-first century with buildings that exclusively use a combination of solar panels on roofs and domestic firewood and used wood as heat-energy sources. These replacement buildings would have density typical of late twentieth-century buildings, and they would need to perform on a low-energy standard of not more than 130 MJ/m2/yr.     

牡竹属三竹种的秆形质量与材性比较

通过牡竹属(Dendrocalamus) 3个竹笋品质佳的竹种（勃氏甜龙竹(D.brandisii)、马来麻竹(D. asper)、花吊丝竹(D. minor var. amoenus)）竹材形态质量及材性比较的研究,结果表明：种间立竹枝下高、相对全高差异显著或极显著,勃氏甜龙竹相对枝下高最小,立竹胸径、全高、枝下高、尖削度值、壁厚率均为最大;竹秆含水率随立竹年龄增大而下降,3年立竹竹秆含水率花吊丝竹>勃氏甜龙竹>马来麻竹,种间差异极显著;相对材积勃氏甜龙竹（1771.35cm 3 cm-1）>马来麻竹（1166.66 cm3 cm-1）>花吊丝竹（659.78 cm3 cm-1）,种间差异极显著;竹材密度随立竹年龄增大而提高,3a立竹竹材密度花吊丝竹（0.914 g.cm-3）>勃氏甜龙竹(0.812 g.cm-3)>马来麻竹（0.749 g.cm-3）,种间差异显著。综合分析勃氏甜龙竹、马来麻竹可作为优良的笋材兼用竹种,花吊丝竹宜作为笋用、观赏竹种推广应用。     

Fruit properties during the harvest period of eleven Indian jujube (Ziziphus mauritiana Lamk.) cultivars

The geometric attributes and physical, mechanical, and chemical properties were determined for 11 Indian jujube (Ziziphus mauritiana Lamk.) cultivars grown in Saudi Arabia including Zaytoni, Kashmiri, Komethry, Um-Sulaem with spines, Toffahy, Um-Sulaem without spines, Abdel-Sattar, Pu-Yun, Pu-Pineau, seedy ber, and buddling ber. The geometric mean diameter, surface area, sphericity, and shape index of the fruits ranged from 20.61 to 42.48 mm, 1339.58–5666.92 mm², 71.39–96.80%, and 110.25–275.18%, respectively. The fruit physical properties, i e fruit weight, fruit volume, stone weight, flesh weight, true fruit density, and pulp-stone ratio varied from 4.71 to 39.02 g, 4.78 to 42.75 cm3, 0.11 to 2.35 g, 4.61 to 36.67 g,0.913 to 1.055 g/cm3, and 7.90 to 43.11, respectively. In addition, the mean color value of L*, a* and b* for the fruits ranged from 64.48 to 96.33, 2.65–4.05, and 6.32–84.36, respectively. The mechanical properties, including elastic range, bioyield force, modulus of elasticity, plastic range, and rupture force ranged from 2.31 to 8.86 mm, 21.64–325.77 N, 14.15–124.09 N/s, 0.83–3.45 mm, 56.42–364.21 N, and 107.77–480.91 N/s, respectively. The greatest rupture force belonged to the Pu-Pineau cultivar and the smallest belonged to the Um-Sulaem without spines cultivar at the horizontal orientation of both cultivars. The fruit chemical analysis values for total soluble solids, titratable acidity, total soluble solids/titratable acidity ratio, and vitamin C ranged from 13.43 to 23.55%, 0.48–1.27%, 14.24–39.85%, and 55.27–164.47 mg/100 g, respectively. The relevant data obtained for the 11 varieties of Indian jujube are valuable for developing and designing machines for processing operations, transportation, separating, packing, sorting, and harvesting. Additionally, the findings revealed considerable variation in chemical content, physical and mechanical characteristics among the tested cultivars.     

香椿优树子代早期生长差异分析及初步选择

来自12个种源的70个香椿(Toona sinensis)优树子代在福建省永春县和华安县进行造林测定试验,调查2年生香椿优树子代测定林生长情况。结果表明,华安2年生香椿优树子代树高1.10～2.80 m,地径1.24～3.72 cm,永春2年生香椿优树子代树高0.91～2.71 m,地径1.18～3.68 cm,华安和永春两个试验点内不同香椿家系的树高和地径差异达到极显著水平(P<0.01)。华安试验点树高和地径的变异系数分别为20.22%和23.68%,初步选出6个早期生长表现优秀的家系,平均树高和地径分别为2.55 m和3.44 cm,平均遗传增益分别为23.70%和30.16%;永春试验点树高和地径的变异系数分别为26.44%和26.48%,初步选出19个早期生长表现优秀的家系,平均树高和地径分别为2.52 m和3.34 cm,平均遗传增益分别为25.07%和24.96%。通过树高和地径的聚类分析与生长比较,70个参试家系可分为优、良、中、差和极差5个类别。综合2个试验点生长表现,初步认定4号、23号、53号和65号等4个家系为优良家系。     

Windthrow damage in <Emphasis Type="Italic">Picea abies</Emphasis> is associated with physical and chemical stem wood properties

On 26 December 1999, the windstorm “Lothar” hit large parts of western and central Europe. In Switzerland, windthrow losses reached 12.7 Mio m³ of timber, corresponding to 2.8 times the annual national timber harvest. Although these exceptional losses were due to extreme peak velocities, recent changes in tree nutrition may have increased forest susceptibility. Previous controlled environment experiments revealed that wood density (associated with wood stiffness) tends to increase in elevated CO₂, and to decrease when N-availability is enhanced (e.g., by soluble N-deposition). Such changes in wood quality could theoretically influence the risk of wind damage. We used the “Lothar” windstorm as a “natural experiment” to explore links between damage and wood properties. In 104 windthrow sites across the Swiss Plateau, more than 1,600 wood cores from (1) broken, (2) uprooted and (3) still standing (not damaged) spruce trees (Picea abies) were collected in February and March 2000. Wood properties, treering width and chemistry of the wood samples were analysed. Broken trees showed wider treerings in the decade 1990–99 compared to non-broken trees (either uprooted or undamaged trees). Broken trees also showed lower non-structural carbohydrate (NSC) concentration in sapwood, reflecting active structural carbohydrate sinks associated with fast growth. There was also a trend for higher tissue N-concentrations in broken trees. No significant differences between damage types were found in wood density and wood shrinkage during desiccation. We conclude that stem breakage risk of P. abies is associated with a stimulation of growth in the past decade and with changes in tree nutritional status. However, the risk for windthrow of whole spruce trees (uprooted but not broken) was not related to the studied wood parameters.