Abstract:详细调查和对比分析了子午岭(富县)天然林地和人工林地土壤水分状况和植被状况,发现天然林地水分亏缺不严重,只在浅层形成了轻度亏缺,并在雨季后能得到及时的恢复;同时这种亏缺并没有影响到天然植被的发育与演替。人工林地土壤水分则亏缺明显,深层亏缺尤为严重,土壤含水量最低平均达到5.90%,已接近凋萎湿度,且这种水分亏缺严重影响了人工林的生存和发展,部分林地已出现了明显的衰退迹象。在此基础上,说明了天然林地土壤水分状况明显优于人工林地的原因是天然林在林分结构上形成了典型的“乔-灌-草”复层稳定的空间层片结构,具有很强的自我调节能力,使天然林在物种的组成成分上逐渐向喜干物种方向发展,以适应气候旱化的总趋势;而人工林则因其结构简单,物种单一,自我调节能力差,在连续干旱的条件下因植被对土壤水分的过度消耗,形成了严重程度不一的土壤干化层。同时,从天然植被的自然水分状况入手,提出了“林地稳定土壤持水量”的概念,来界定土壤干化现象:依据土壤水分的亏缺现状初步将干化程度分为轻度干层(8%～10%)、中度干层(6%～8%)和严重干层(<6%)3个等级;依据土壤水分的补偿深度又将其划分为临时性干层和持续性干层。研究认为,当前人工林地的土壤水分出现严重亏缺而形成土壤干化层是人为不合理经营造成人工林群落林分结构不完善的结果,如果人为干预适当,能创造出类似于天然植被的生存条件,人工植被完全有可能得到正常的生存和发展。

Abstract:As the distance from the river course in the lower reaches of Tarim River at different planes prolonged and thus made the water table become deep,the MDA content and SOD activity of \%Tamarix ramosissima\% leaves increased with deepened water table showin

Abstract:In the sand regions of the Minqianxian County,the coverage of desert plants remarkably varies with year-by-year rainfall fluctuation in which the vegetations degenerate.Kraurosis takes place on the top parts of upper Nitraria tangutorum,Haloxylon ammodend

Abstract:小叶杨是黄土高原主要水土保持树种之一,但营造坡位和方式的不同,其生长的空间差异显著。研究表明,坡下部小叶杨平均地径、胸径、枝下高和冠幅等参数都明显优于坡中部和上部,以沟谷地带的小叶杨生长为基点,则坡下部、中部和上部的小叶杨的树高和胸径生长潜力分别为沟谷地带小叶杨的77.53%、34.88%、31.88%和75.59%、39.51%、33.36%;小叶杨(+沙棘)混交林,其林分的平均树高、地径、胸径及冠幅等生长参数都明显高于纯小叶杨林,混交小叶杨林比纯小叶杨林有更好的稳定性。小叶杨林地土壤水分变化规律:坡下>坡中>坡上,随坡位升高,其差值逐步增大;混交比纯林模式对深层土壤水分的消耗更大;在100～500cm土层的小叶杨林地普遍存在低于凋萎湿度的土壤干层,即使通过雨季降水的补充也难以恢复。

Abstract:Tamarix ramosissima Ledeb., Haloxylon ammodendron (C.A.Mey) and Teaumuria soongorica (Pall.) Maxim.,three primitive and xeric desert shrubs growing and dominating in the southern boundary of the Garbantunggut desert,were tracked with The LI-6400 system by

Abstract:The two-way indicator species analysis and the correspondence analysis were adopted to classify and rank the forae naturally recuperating on 33 sample sites distributed in Ansai county standing in the hilly and gully regions of the loess plateau.The resul

Abstract:The study was conducted in the loess plateau to explore the relations between plant and insect communities in vegetation rehabilitation and evaluate the rationalities of the combinations of artificial and naturally-regenerating vegetations,thus providing

Abstract:通过野外调查与实验室分析相结合的方法,对关帝山山地寒温性针叶林下更新幼苗数量与土壤pH值、氨态氮、有效磷、速效钾进行了调查和分析测定,对华北落叶松和云杉林下更新幼苗数量与土壤因子的关系进行相关分析,并对林下更新与其主要影响因子之间的对应关系进行了分析。结果表明,在调查分析的土壤营养状况范围内,华北落叶松林下更新幼苗数量与土壤pH值、氨态氮含量呈负相关,与有效磷、速效钾含量呈正相关,4个因子对华北落叶松幼苗更新的影响强度为:土壤pH值>氨态氮>速效钾>有效磷,土壤pH值和氨态氮是影响其林下更新的主要因子,华北落叶松的适宜林下更新的土壤pH值为6.5～6.7,土壤氨态氮含量为9.3～11.5mg·L-1;云杉林下更新幼苗数量与林下土壤pH值呈负相关,与氨态氮、有效磷、速效钾含量均呈正相关,4个因子对云杉林下更新的影响强度为:有效磷>速效钾>氨态氮>土壤pH值,有效磷和速效钾是影响林下更新的主要因子,云杉更新适宜的有效磷含量为14.0～16.0mg·L-1,速效钾含量为119～153mg·L-1。在此基础上就今后研究应解决的主要问题提出了建议。

Abstract:用植物冠层半球影像系统分析测定了黄土高原腹地子下岭林区4个小同龄级油松林的，冠层特征和林下光立地系数，并应用α多样性指数对不同龄级人工油松林群落的生物多样性进行了初步研究。结果显示，该地区人工油松林叶面积指数(LAI)在林木生长20a以后达到稳定值；平均叶倾角(MLA)但40a内变化不大；冠型参数(ELADP)的数值作40a内呈U型波动；综合光立地系数(GSF)、直射光立地系数(DSF)、散射光直：地系数(ISF)等参数显示，该地区人工油松林在发育过程中，林下光照明显下降．40a林下光照条件各项指标仅约为10a林的1／3。群落内的生物多样性指数有随年份增长而降低的趋势。

Abstract:The properties of the soils and the constituents of the Lycium barbarum fruits from the four major regions of medlar production were measured or determined to study the effects of different soil properties on the contents of polysaccharide and total sugar

Abstract:The pit-membrane remnants in the perforation plate of the vessels in the secondary xylem of Euptelea pleiospermum were examined,which showed that there existed rich and diverse types of pit-membrane remnants including nearly complete pit membrane,and comp

Abstract:运用光学和电子显微镜对银杏雄配子体发育进行了研究。结果显示，花粉粒进入贮粉室后，通过侧向萌发产生吸器状花粉管。精原细胞在发育过程中依次产生生毛体、液泡状结构和纤维颗粒体。生毛体由一个电子致密的核心和由此向周围发散出的辐射状中心粒组成；液泡状结构为染色较深、质地均匀，看不到膜结构包被的圆球形，其周围细胞器丰富，DAPI染色证实液泡状结构中含有遗传物质。纤维颗粒体染色很深，外形小规则。临近受精前，精原细胞纵向分裂形成2个半球形的精细胞，成熟精核直径约40μm，而受精时与卵核融合的精核直径约20μm，说明精核在受精前体积浓缩。精核以变形虫式运动穿过较小的颈卵器口，进入卵细胞与卵核融合。在受精前的一些精细胞中可观察到其核内出现一个直径约20～30μm染色较深的球形区域，推测精核浓缩前遗传物质先浓缩到一个区域，然后精核浓缩。

Abstract:Optical microscopy and transmission electron microscopy was adopted to in vitro study the effects of the stylar S-RNase of different pear varieties on the germinations,and pollen-tube growths and ultra-structures of autogamous (compatible) and xenogamou (

Abstract:报道了酞酸酯类化合物DBP对拟南芥离体培养叶片超微结构的影响。在DBP(1.0mg·L-1)处理第3天即观察到拟南芥叶片叶绿体的超微结构受到破坏。不同浓度的DBP长期处理植株(40d)出现叶片白化、节间短缩等异常现象。在0.01mg·L-1DBP处理40d植株的叶细胞中,叶绿体出现解体,破碎部分呈颗粒状,散落其间,但细胞结构完整;0.1mg·L-1DBP处理后引起叶绿体的进一步解体,叶绿体中类囊体基粒和片层结构解体,细胞出现空洞现象,其它细胞器很少观察到;1.0mg·L-1DBP和2.0mg·L-1DBP处理植株叶片叶绿体中类囊体基粒和片层结构破碎,叶绿体结构也解体,细胞中其它细胞器数目极少。

Abstract:Expression analysis of wheat TaMlo-A1c gene,which was related to powdery mildew resistance in wheat,was carried out by semi-QRT-PCR,using wheat Actin gene as a control.The results showed that TaMlo-A1c gene was expressed in leaves,stem and root,no express

Abstract:从生物信息学角度，利用http://www.us.expasy.org、http://www.ch.embnet.org和NCBI的核酸/蛋白质结构特征在线分析工具，对棉花蔗糖合成酶（SuSy,sucrose synthase E.C.2.4.1.13）基因及其推导的氨基酸序列进行结构特征和功能域预测分析，探讨了棉花蔗糖合成酶的亲/疏水性、信号肽、跨膜拓扑结构、卷曲螺旋结构及功能域。结果表明该酶具有2个卷曲螺旋区段；20-30和190-215氨基酸区域，没有信号肽，是一个非跨膜的亲水性稳定蛋白，包含两个功能结构域7-555（Sucrosc-synth）和568-747（Glycose-transf-1），分别行使蔗糖合成功能，糖基化合物（UDP、ADP、GDP或CMP）转移功能。

Abstract:Binary phyto-vector pBIcal of calreticulin was first constructed to probe the feasibility to use phyto-secretion to express recombinant proteins,the cholera toxin B subunit gene was then transferred into the vector,and expression vector pBIcal-ctb was fin

Abstract:克隆枯草芽孢杆菌纤溶酶(Bacillussubtilisfibrinolyticenzyme,BSFE)基因及其前导肽序列。通过农杆菌EHA105介导转化,获得转基因烟草植株。其BSFE的表达水平为叶片42.97±28.59U·g-1FW、茎15.14±10.57U·g-1FW和根25.55±14.71U·g-1FW。其内源BSFE信号肽可在转基因烟草中行使蛋白转运功能,使BSFE具有分泌表达特性。这一系统可用于建立利用植物组织分泌表达外源蛋白的系统模型。

Abstract:The objective is to clone the gene encoding the recombinant human granulocyte colony-stimulating factor in Anabaena sp.PCC 7120 for preparing oral drug.On the principle of codon degeneracy,the codons of the first four amino acids of G-CSF were altered by

Abstract:The study conducted PCR amplification of the designed primers to obtain green-fluorescent protein gene,and the PCR products,after being enzyme digested,were connected with TuMv virus-expressing vector to produce the positive clones for which PCR identific

Abstract:Polyacrylamide gel electrophoresis was adopted to investigate the variation patterns of allozyme bands of four enzymatic systems in six species of Ranunculus Linn.and then the dimorphic data about the allozyme bands were analyzed by correlation analysis a

Abstract:RAPD markers were used to estimate the genetic diversity of the genus Lonicera Linn.and to assess the genetic relationships among 23 species in Gansu Province.Nine primers that produced clear and reproducible bands were screened from 34 arbitrary primers

Abstract:Haynaldia villosa is one of the important parental materials to improve the quality of common wheat.The whole coding sequence of a new HMW-GS (high molecular weight glutenin subunit) gene ( hayvi G 1) was obtained by PCR amplification from Hayaldia villos

Abstract:Yedan 22,a common maize type,and Gaoyou 115,a high-oil maize type,were used to study the protein and protein component,albumin,globin,gliadin and glutelin contents and the total amino acid content and the contents of individual amino acids in the grains o

Abstract:对水母雪莲细胞悬浮培养过程中细胞生长、黄酮积累和底物消耗的动力学过程进行了研究.经15 d液体培养可获得最大生物量干重和黄酮产量分别为17.2 g·L-1和607.8 mg·L-1,通过调控基本培养基种类和有机添加物可提高雪莲细胞的生长和黄酮积累.获得的水母雪莲细胞培养物具有明显的抗氧化活性,其抗氧化活性与雪莲细胞中的黄酮含量相关.

Abstract:The physiological and biochemical indexes were studied in cucumber seedlings grafted on wild cucumber ( Sicyos angulatus L.) rootstocks,black seed pumpkin rootstocks and self-rooted cucumbers.The results showed that the activities of SOD,POD,CAT and the c

Abstract:505 vegetable materials of Brassica campestris ,such as Chinese cabbage,no-heading Chinese-cabbage and purple Tsai-tai,were field observed and identified,and 90 materials of their representative types (30 materials per type) were sampled to investigate th

Abstract:不同化学试剂组合对四季花龙眼枝梢生长和成花座果研究表明,不同时期成熟的枝梢对四季花龙眼成花座果无重大的影响;乙烯利、多效唑和赤霉素三者共同作用可促进成花座果;当枝梢充分成熟时,树冠喷施乙烯利250mg·L-1+多效唑450mg·L-1,谢花3/4时再喷施赤霉素50mg·L-1,可以有效抑制四季花龙眼植株新梢的萌发,促使植株100%成花,并且花穗和果穗性状的综合表现最好。

Abstract:The classification, composition and characteristics of pteridophyte flora in the Loess Plateau were investigated.The results revealed that the pteridophytes in the Loess Plateau consisted of 184 species and 3 varieties,53 genera and 26 families.Of the pte

Abstract:The early-maturity nectarine varieties,Huaguang and Shuguang,were used to study such factors as growth regulator concentrations and combinations,culture mediums,stage of embryo development,and low temperature that affected the regeneration of their embryo

Abstract:通过丛生芽直接增殖和愈伤组织再分化两条途径建立紫茎泽兰的无性系,可为进一步研究紫茎泽兰入侵的分子生态机制提供植物材料。结果表明:MS+BA2.0mg·L-1+NAA0.05mg·L-1为丛生芽增殖的最适培养基,MS+BA0.1mg·L-1+NAA0.1mg·L-1和MS+BA2.0mg·L-1+NAA0.2mg·L-1分别适于叶片愈伤组织的诱导和分化,而1/2MS+IAA0.1mg·L-1对生根最有利。

Abstract:为了研究菜豆种子超干贮藏的适宜含水量及其机理，采用人工老化法对不同含水量的菜豆种子在老化过程中的活力变化与生理特性进行了研究。通过对含水量为3．4％～9．0％老化菜豆种子的发芽率、脱氢酶和酸性磷酸酶活性以及丙二醛含量等指标的检测，结果表明菜豆种子含水量(MC)降至3．8％，能显著提高抗老化劣变的能力。在同等老化处理(50C、20d)后，未超干种子(MC=6．9％～9．0％)发芽率已大幅度下降，而超干种子(MC=3．8％～3．4％)的发芽率仍保持一个很高的水平。与未超干种子相比，超干种子脱氢酶和酸性磷酸酶活性明显升高，而丙二醛含量则显著降低。不同含水量菜豆种子POD同工酶谱不同。

Abstract:赤霉素(GA3)和脱落酸(ABA)是果实组织中的两个重要激素,本试验用SymmetryC18色谱柱(4.6mm×150mm),以乙腈和1.8%乙酸[V(CH3CN)∶V(1.8%CH3COOH)=1∶1]为流动相,流速为0.5mL·min-1,Wa-ters2487UV-检测器,在检测波长254nm,柱温25℃的条件下,同时分离并测定了银凤桃中的GA3和ABA。GA3和ABA的分离效果理想,回收率分别达到100.1%和99.8%,该方法测量灵敏度达10-2ng·g-1,精密度RSD%<0.1。

Abstract:The suspension cultures on the callus obtained from tender leaves of the Wuyuan tea were conducted on a shaking table and in a fermenter and then effects of different adding modes and shearing forces of ZtNH_2-HCl,the synthetic precursor of theanine,on th

Abstract:采用ISO9842:2003玫瑰油标准,对陕西商州引种的保加利亚主栽玫瑰品种“Kazanluk”(RosadamascenaMiller)精油进行分析。结果表明,该玫瑰精油香气具有天然玫瑰花香,香气细腻、柔和、飘逸。油为液体,淡黄色,相对密度(20/20℃)0.8599,折光指数(20℃)1.4592,旋光度(20℃)-4.3°,冻点20.6℃,酯值11.9,这些物理指标达到了标准要求。大量主香成分相对含量:乙醇0.5%,香茅醇45.5%,橙花醇4.5%,香叶醇7.6%,苯乙醇2.9%,十七烷烃1.13%,十九烷烃15.5%,二十一烷烃5.0%。这些成分含量与原产地保加利亚玫瑰油成分范围有一定差异,但与摩洛哥同类玫瑰油标准相符,可以作为商品油在国际市场销售。

Abstract:In the biodiversity studies,pattern of plant species diversity along elevational gradient is one of the basic issues.But there is no consistent agreement until now.We reviewed plant diversity patterns for 19 mountains in China,and compared their patterns

Abstract:Reactive oxygen has a dual function that it damages cells at high concentrations and protects cells at low concentrations.Under photo-oxidative stress,the highly energetic reactions in photosynthesis,along with sufficient oxygen supply,makes chloroplasts