Abstract:Soil pot and hydroponic experiments were conducted to compare root morphological features and root exudation characteristics of difference soybean [ Glycine max (L ) Merrill] varieties The results indicated that genetic variation existed among the tested cultivars Under low phosphorus condition, a soybean cultivar, Nanxiong 36 , had relatively higher phosphorus efficiency than the other cultivars used Under phosphorus deficiency, root shoot ratio,tap root length, root total absorbing area and active absorbing area of soybean did not show a clear pattern of variation, hence these parameters should not be considered as specific indices of phosphorus efficiency At low phosphorus availability, soybean exuded higher amount of total acid and H + than at high phosphorus availability At low phosphorus level both total acid and H +exuded by variety Nanxiong 36 were significantly higher than the other cultivars At low phosphorus level the quantity of oxalic acid exuded by soybean roots was in general higher than those at high phosphorus level The quantity of oxalic acid and lactic acid exuded by Nanxiong 36 was relatively higher, which might imply that this cultivar has the genetic potential in solubilizing unavailable phosphorus in the soil, and hence has higher phosphorus efficiency

Abstract:研究了广州白云山风景名胜区森林群落的物种多样性，利用Simpson指数和Shannon-Wiener指数，按群落类型计算了各群落的总体多样性指数和均匀度，不同层次和不同径级的多样性指数和均匀度，各群落的Simpson多样性指数为4.5379-9.3591，均匀度为0.1782-0.4288,Shannon-Wiener多样性指数为2.7672-3.6691，均匀度为0.6637-0.8119，其数值下鼎湖山和粤北南岭国家级自然保护区天然林的相关研究接近，但物种丰富度则较低，多样性指数值的高低与各群落所受干扰程度有关，受干扰程度最小的“荷木＋中华锥－九节”群落，其Shannon-Wiener多样性指数最高，同时各群落的幼苗层均具较高的多样性指数，显示出群落有较强的天然更新潜力。

Abstract:用样方取样法对粤北小红栲 (Castanopsiscarlesii)林进行调查 ,并对粤北小红栲林结构特征进行了研究 结果表明 ,粤北小红栲林的植物种类繁杂 ,在 6 30 0m2 的样方面积中有维管束植物 184种 ,隶属于 5 9科 12 3属 优势科为壳斗科、樟科、茶科等 ;植物区系具有明显的热带亚热带性质 ;区系的地理成分以泛热带分布和热带亚洲分布的属为主 ,是广东植物区系的重要组成部分 ,隶属于华南省中的粤北 -闽西南亚省 ,归属于东亚植物区华夏植物界 粤北小红栲林植物的生活型谱以中高位芽植物和小高位芽植物占优势 粤北小红栲林的成层现象明显 ,可划分为乔木层、灌木层、草本层 ,乔木层可再划分为 2个亚层 乔木、灌木的植物种类较多 ,草本植物和层间植物种类较少 粤北小红栲林的林分密度为 3144株·hm 2 ,林木的平均距离为 1.69m

Abstract:Based on the sustainable development idea and the eco economic theory, the social and economic conditions of Zhongshan city was analyzed and it was divided into 4 eco economic regions: the central town constructive region and the nature conservation region, the industrial eco developmental region, the opening agricultural region, and the eco environmental constructive region Sustainable developmental measures was proposed for the city in society, economy, resource and environment aspects

Abstract:根据贝塔朗菲系统自生长的微分方程 ,可建立表征土壤生态系统动态变化的动力学方程 :dx/dt =(f-s)x-bx2 ,t为时间 ,x为土壤微生物数量 ,f为其繁殖系数 ,s为死亡系数 ,b为饱和系数 .其解 (1)x=x0 e(f-s)t,(2 )x =(f -s) /b.方程 (1)表明 ,如s>f,则当t→∞时 ,x→ 0 ,表明土壤生态系统处于热力学分支 ,将向退化的方向发展 ;方程 (2 )表明 ,如f>s ,其临界点x =(f -s) /b ,如x>x ,则表明土壤生态系统处于耗散结构分支 ,将向进化的方向演替

Abstract:The substance FI 5 was isolated from the seeds of introduced neem trees ( Azadirachta indica A. Juss) planted in China by open column chromatography on silica gel. On the basis of spectroscopic analysis its structure was identified as azadirachtin. The result of no choice antifeedant experiment against the larvae of Pieris rapae showed that it had the most potential antifeedant activity.

Abstract:Rotentone was characterized by single crystal X ray analysis Crystal data: Orthorhombic, space group P 2 12 12 1, a =0 8417 8(1), b =1 986 9(3), c =2 361 8(4)nm, V = 3 950(1) nm 3, Z = 8 The crystal structure shows that there are two stereoisomerides of rotenone in solid state

Abstract:研究温湿度因素对斜纹夜蛾实验种群影响结果表明，在适温范围内，温度与各虫态发育率呈直线关系，卵，幼虫期，蛹（♀）蛹（♂）发育点温度分别为12.66,11.40,11.70,13.08℃，发育上限温度为40.53,36.99,36.10,38.47℃，湿度是影响幼虫取食的重要因子，斜纹夜蛾蛹质量（♀），蛹质量（♂），成虫产卵量受温湿度因子的综合作用。

Abstract:By regular gene cloning techniques, DNA component 6 of the representative isolate of BBTV (banan bunchy top virus) NS strain was cloned and sequenced. The sequence was compared with the sequence of DNA component 6 of Guangzhou Tianhe isolate (belong to NSP strain) reported. The results showed that the variance ratios of full sequence of the component 6,the ORF nucleotide sequence and its encoding amino acid sequence between the two isolates were 3 4%, 1.7% and 2.6% respectively.Results in the experiment showed that the differences of the component between the two representative isolates of the NSP and NS strains respectively were significant, and that further supported that there were NSP and NS strains of Guangdong BBTV. In addition, the variance ratios of the full sequences of the component, the ORF nucleotide sequences and its encoding CP amino acid sequences were 14.4%, 7 5% and 7 1% respectively between the Gaozhou isolate and the Australia isolate.

Abstract:Nitrate reductase (NR, EC 1.6.6.1) activity in wheat( Triticum aestivum L.) leaves changed rapidly and reversibly during light/dark transitions. Darkness decreased and light increased the activity of nitrate reductase. NR extracted from leaves in dark showed more sensitive to inhibition by Mg 2+ than that from lighted leaves. The NR from darkened leaves and lighted leaves showed marked different in the time course of nitrate reduction. These results indicated that the darkness treatment could change the modulation characteristics of nitrate reductase.

Abstract:The rooting abilities in different species of Eucalyptus are quite different. The stem anatomy and histochemistry of Eucalyptus species, i.e. Eucalyptus ABL No.12 W5 clone, E.urophylla MLA clone, E. exserta and E. citriodora , were studied. It was indicated that those stem cuttings of Eucalyptus species, which had relatively developed and relatively lignified rays, relatively high content and relatively extensive distribution of phenol substances, were easy to form root primordia and then easy to root.

Abstract:A pair of 23 bp primers, designed according to a conserved sequence of the APETALA1(AP1) gene which has an important function in floral development, were used to amplify a 648 bp fragment by polymerase chain reaction(PCR). The fragment was cloned into pUCm T vector, and then sequenced. A fragment in the middle of AP1 homologous gene named ZM AP1 gene was obtained. The result of sequence analysis indicated that there were two introns of 152 bp and 386 bp in the fragment, and the exons encoded 36 amino acids. The ZM AP1 gene has been registered in GenBank with the accession number AF356541. After the deduced amino acid sequence of the fragment was submitted to GenBank and blast with AP1 homologous gene of other plants, it was found that the homology reached 66%-88%. This result suggested that ZM AP1 gene might have the same function as other AP1 homologous gene.

Abstract:从单胃动物的粪便垃圾堆中分离出一种可分泌植酸酶的青霉 .进一步的研究表明这种青霉培养液最佳的淀粉含量为 40g·L-1.青霉生长与其分泌植酸酶之间存在矛盾 .青霉生长旺盛时产酶少 ,测出的酶活性低 .青霉生长缓慢时产酶多 ,测出的酶活性高 .植酸酶大量分泌前伴随着培养液pH值的急剧下降

Abstract:利用胡萝卜下胚轴愈伤组织，以HgCl2为选择剂，通过多步正筛选法，获得了抗性变异细胞系，抗性鉴定结果表明，在不同HgCl2浓度的培养基上，抗性系的愈佃组织存活率和鲜质量增殖率均显高过亲本系，抗性系的细胞膜透性也发生了变化，对抗性系和亲本系愈伤组织进行再分化的结果表明，在连续3－4代的分化培养之后，愈伤组织都能再生绿苗，提出了该项研究在预防和治理重金属污染方面的重要意义。

Abstract:以中花介蓝为材料，研究了不同保鲜剂对其保鲜效果和营养品质的影响，经表表明：在低温和自发气调的贮存方式,自制保鲜剂的保鲜效果最好,在30d的保鲜过程中，自制保鲜剂处理的芥蓝，可溶性蛋白含量，叶绿素含量，可溶性糖含量，维生素C含量下降都是最慢的。

Abstract:The effects of shading on plant growth and leaf microstructure of Thunbergia grandiflora (Rottl. et Willd.) Roxb. and T. Laurifolia Lindl. were studied. The results showed that the height of plant, length of internode ,chlorophyll content and the leaf tissue structure loose ratio ( SR ) increased, but chlorophyll a/chlorophyll b, thickness of leaf, palisade tissue and spongy tissue, the tissue structure tense ratio ( CTR ) decreased.

Abstract:In the approaches of constructing recombinant vaccines based on avian vasoactive intestinal peptide (VIP), human hepatitis B core antigen (HBcAg) cDNA was chosen as the carrier for the purpose of enhancing immunogenicity of goose VIP. The VIP cDNA sequence and the 1 st to 435 th bp sequence of HBc cDNA (coding for 1 st to 145 th amino acid residues of HBcAg) were respectively amplified and inserted into BamH I\ Pst I and Nhe I\ BamH I cloning sites of plasmid pRSET A to produce plasmid pHBc VIP containing the HBc VIP fusion gene, which would express a fusion protein with VIP positioned posterior to the 145 th amino acid residue of HBcAg. Then the 1 st to 225 th bp sequence of HBc cDNA amplified, and the sequence starting from 244 th bp of HBc cDNA to the end of VIP sequence of pHBc VIP was amplified, digested with EcoR I, ligated and then amplified were respectively inserted into the BamH I\ Pst I and the Pst I\ Hind III cloning sites of plasmid pBSKS +/- to construct plasmid pVIP HBc, which contains a fusion gene with VIP sequence inserted into the middle of HBc cDNA, and coding for a fusion protein with VIP sequence inserted into the 75 th and 83 rd amino acid residue positions of HBcAg.

Abstract:A cDNA fragment coding for VP5 and noncoding regions of three strains of IBDV were amplified by reverse transcription polymerase chain reaction (RT PCR) from the genomic dsRNA of CJ801, LX, HK46 respectively. The amplified cDNAs of three strains were cloned into the plasmid pBssk to generate recombinant plasmids, and to be used for sequencing. This experiment is the report about the sequence of VP5 and noncoding regions of CJ801 and LX. The VP5 of most strains consist of 145 AA and has only one hydrophilic region, whereas the VP5 of vvIBDV and variant strains consist of 149 AA and has two hydrophilic regions, which may contribute to virulence variation.

Abstract:采用 3× 2二因子析因设计 ,研究环境温度 (5～ 15、2 0～ 2 5、30～ 35℃ )、消化道排空期时数 (32和 48h)对消化道残留内容物含量的影响 .结果表明 ,环境温度显著影响绝食鸡消化道残留内容物干物质量 ,而且以低温 5～ 15℃时影响较大 ;排空期 32和 48h对胃、小肠、直肠和泄殖腔中内容物干物质含量差异不显著 ,而对盲肠内容物或整个消化道内容物总和有显著影响 .可见 ,在决策排空期时数时应考虑环境温度因素

Abstract:将SS，KMI，KMIII3个禽流感病毒的感染性胚液分别中2周龄及5周龄的SPF鸡，观察其症状及病理变化。结果显示：1，3个毒株均可引起攻毒鸡体温升高，部分出现水样淡黄色稀粪，但不能致死攻毒鸡，表明3个毒株均为非高致病力毒株，2，攻毒鸡除胰腺充血出血外，其他器官不见明显的肉眼病理变化，但组织病理病理学的变化较为明显和一致，主要为：脑及脊髓充血出血，神经元变性坏死，胶质细胞增生；心肌在出血，组织变性坏列, 腺充血出血，组织坏死，3个毒株对5周龄SPF鸡的病理变化无明显差异，但KMI毒株对2周龄SPF鸡的病理损害稍大于SS株。

Abstract:According to practical needs, a novel enterprise marketing decision support system (DSS) is devised by using the Internet/Intranet technology The paper mainly discusses the design and realizations of man machine interface, data base subsystem and model base subsystem of enterprise marketing DSS based on Intranet mode The design approach of this system is generally applicable to a certain extent, and is valuable reference for other DSS designs of government organs, universities or scientific research institutions

Abstract:利用人工神经网络神经元之间的非线性性，将BP神经网络理论应用于温室环境自动检测系统数学模型的建立中，讨论了网络结构的设计，学习算法等问题，温度检测结果的统计试验表明，与温度真实值比较平均误差是0.4℃，结果合乎温室环境检测要求，使用结果表明，系统采用修正数学模型的方法进行调试，减少了硬件调试的困难，方便检测系统在田间的安装与维护。

Abstract:When computer vision was applied to fruit detection, the background and sample of an image could be effectively segmented with the aid of boundary tracking technique. According to the appearance of some fruit, such as pear and apple, a modified boundary tracking method was proposed. In this method, a sample in an operation image that could be binary image or gray image was partitioned into 4 regions. To accelerate the boundary tracking, the priority of boundary tracking directions in each region was given by the appearance of the sample. Lastly, tests of boundary tracking using images of apples, pears, mango etc. were done. The results confirmed that the time of processing a 150 by 150 image of a pear was less than 1 s.

Abstract:Particleboard gives rise to wet stress in the course of manufacture and use owing to the change of moisture content. The result shows that the wet stress caused by wet effect is about 0.21 MPa, accounting for 13.4% of the average interface combination intensity reduction value. Qualitative and quantitative appraisal of wet stress is critically important to enhance the combination stability at interface.

Abstract:In this paper, the general biological characters of earthworm were first introduced in brief. Then the effective components of medication and nutrition from earthworm were reviewed in detail, especially for several kinds enzymes which have potential application in medication. These included earthworm fibrinolytic enzyme(EFE), Lumbrokinase and so on. The purification, characters and medical function of these enzymes were concerned. Finally a conclusion was reached that exploration of earthworm would play important roles for high tech agricultural development and environmental protection.

Abstract:肝细胞的分离技术是开展离体肝细胞培养及研究的前提 ,细胞的分离效果直接影响离体细胞的成活率、细胞纯度以及细胞分裂增殖的能力 以往多采用机械分离法和肝组织酶解分离法分离哺乳动物肝细胞[1,2 ] ,但这 2种方法均存在细胞破损较严重、肝细胞中混杂大量红细胞等缺点 ,对肝细胞的成活率及细胞纯度产生较大影响 本试验采用肝脏原位灌流法分离大鼠肝细胞 ,获得了较为理想的分离效果 1　材料与方法试验动物采用 30日龄ＳＤ大鼠 ,购自中山医科大学实验动物中心 培养基为ＲＰＭＩ 1640 (ＧＩＢＣＯ公司 ) ,胶原酶为Ｓｉｇ ｍａ产品 ,小牛血…

Abstract:近年来 ,我国荔枝种植业发展迅速 ,1999年产量达到了65万ｔ,成为荔枝生产最多的国家 .但是 ,由于荔枝采收期集中、采收时又正值高温季节、加之极不耐贮藏 ,因而常出现因果皮褐变和腐烂变质而导致较大的损耗 ,因此 ,在重视保鲜的同时 ,必须发展荔枝加工 ,这是世界水果生产发展的必然 .荔枝因其原料的特点 ,适合加工成澄清果汁 .澄清果汁加工通常利用澄清助剂 ,如皂土、硅藻土、明胶、硅溶胶、单宁、聚乙烯吡咯烷酮或它们的联合使用来达到澄清的目的[1] .近年来 ,有不少报道表明壳聚糖[2 ] 和蜂蜜[3 ] 是加工澄清果汁的良好澄清剂 .本研究的目…

Abstract:伏令夏橙 (ＣｉｔｒｕｓｓｉｎｅｎｓｉｓＯｓｂ)是我国重要的反季节鲜果之一 ,但采后螨害严重 笔者选择 0 3～ 0 6ｋＧｙ剂量辐照杀螨 ,并对杀螨后伏令夏橙果实营养成分和贮存期间生理效应的变化做了初步的研究 1　材料与方法辐照剂量 :0 (ＣＫ)、0 3、0 4、0 5、0 6ｋＧｙ .供试果实采于广东四会县 ＳＯＤ活性用ＮＢＴ法 ,以抑制氯化硝基四氮唑兰降解 5 0 %作为一个酶活单位 (Ｕ) ;ＰＯＤ活性用愈创木酚氧化比色法 ,以每分钟下降 0 0 1光密度值为 1个酶活单位 (Ｕ) ;果实失重率用重量法 ;果皮透性以相对电导率表示 Ｖｃ含量用2…

Abstract:桄榔 (南方草木状 )ＡｒｅｎｇａｗｅｓｔｅｒｈｏｕｔｉｉＧｒｉｆｆ.ｉｎＣａｌｃ.Ｊｏｕｒｎ .Ｎａｔ.Ｈｉｓｔ. 5 :474.1845Ａｒｅｎｇａｐｉｎｎａｔａｓｅｎｓｕｎｏｎ (Ｗｕｒｍｂ .)Ｍｅｒｒ.;中国植物志 13(1) :110 ,Ｐｌ.2 5 (1～ 6) ,1991;海南植物志 4:167,Ｐｌ.10 68,1977;广东植物志 2 :45 2 ,1991.分布 :海南、广西及云南南部至东南部 ,生于海拔 60 0ｍ以下的山地密林或疏林中 中南半岛及东南亚亦有分布 Ｈａｉｎａｎ(海南 ) :Ｙａｘｉａｎ(崖县 ) ,Ｆ .Ｃ .Ｈｏｗ(侯宽昭 ) 70 690 ;Ｌｅｄｏｎｇ(乐东 ) ,Ｌａｕ (刘心祈 …

Abstract:通常 ,我们设Ｒ代表实数域 ,Ｍｎ(Ｒ)代表所有ｎ×ｎ阶实数矩阵的集合 .假定Ａ =(αｉ) ｊ∈Ｍｎ(Ｒ) ,系数α ,β {1,2 ,… ,ｎ},我们用Ａ(α ,β)表示矩阵Ａ中处于α行和β列的子阶矩阵 ,特别地 ,Ａ中元素αｉｊ=Ａ({ｉ},{ｊ}) Ａｉｊ代表αｉｊ的代数余子式 ,即　　Ａｉｊ=(- 1) ｉ+ｊｄｅｔ(Ａ) ({1,… ,ｉ- 1,ｉ + 1,… ,ｎ},{1,… ,ｊ- 1,ｊ+ 1,… ,ｎ}) .Ａ的伴随矩阵定义为 :ａｄｊ(Ａ) =(Ａｉｊ) =Ａ11Ａ2 1…Ａｎ1Ａ12 Ａ2 2 …Ａｎ2…………Ａ1ｎ Ａ2ｎ …Ａｎｎ.　　定理[1] 　设Ａ =(αｉｊ)∈Ｍｎ(Ｒ)是一个实幂等矩阵 ,则Ａ…