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1.
数字或英文-甲基咪唑(689)-磷酸葡萄糖酸脱氢酶(139)30nm(444)BA(228)BC模型(346)O基因(352)RC1(461)t毒蛋白(733)a2+(319)DNA文库(61)1蛋白的周转(486)NA的复制(280)C(319)g2++POD(531)SSR(326)APK(205)APK级联(205)DA(667)g2+(319)CED基因(352)OD(531)(667)SⅠ复合物(444)SⅡ反应中心失活(486)NA干涉(719)CR(461)LF基因(755)NP(618)OD(531)(667)RK(461)-Rnase基因(755)teedman抯wax(547)基因型(755)中文一画一氧化氮(NO)(44)乙烯(216)乙酰化(689)中文二画二苯基苦基苯肼自由基(74)人工神经网络(429)中文三画大…  相似文献   

2.
本文运用广义Riccati变换和中值定理,讨论了广义Emden-Fowler方程(r(t)|z'(t)|~(α-1)z'(t))'+q(t)|x(σ(t))|~(β-1)x(σ(t))=0的振动性,其中z(t)=x(t)+p(t)x(τ(t)),β≥α0,得到了该方程存在振动解的充分条件,推广和改进了已有结果,并用实例给出了其应用.  相似文献   

3.
设A_(11)A_(12)B_(11)B_(12)…N_(11)N_(12)和A_(21)A_(21)B_(21)B_(21)…N_(21)N_(22)分别是亲本P_1和P_2的基因型;a_(11),a_(12),a_(21)和a_(22)是控制同一性状的一组具有显隐关系的等位基因(a=A,…,N)。假定这n组等位基因互不连锁,且一组等位基因与另一组等位基因间没有相互作用,那么公式  相似文献   

4.
主编(Editor in chief)李伯刚(LiBogang)执行主编(ExecutiveEditor in chief)王俨(WangYan)副主编(AssociateEditors)周正质(ZhouZhengzhi)张浙川(ZhangZhechuan)编委(MembersofEditorialBoard)孙汉董院士(SunHandong)张礼和院士(ZhangLihe)陈竺院士(ChenZhu)陈凯先院士(ChenKaixian)周俊院士(ZhouJun)林国强院士(LinGuoqiang)徐任生院士(XuRensheng)丁立生(DingLisheng)及元乔(JiYuanqiao)孔令义(KongLingyi)王锋鹏(WangFengpeng)车镇涛(CheChuntao)北中进(SusumuKitanaka)石任兵(ShiRenbing)刘忠荣(LiuZhongrong)吴天…  相似文献   

5.
本文从实际问题出发,结合已有的描述群落生态的数学模型,提出了一组描述马尾松毛虫(Dendrolimus pnnctalus,walker)、条毒蛾(Lymantria dissoluta,Swinhoe)、天敌和食料之间动态关系的数学模型: w(k+1=(a_1x(k+1)/(1+a_2x(k+1)/_z(k))+a_3w(k)/(1+a_4w(k)/y(k)) x(k+1)=b_1w(k)/(1+b_2w(k)/y(k))+b_3x(k)/(1+b_4x(k)/z(k))+ y(k+1)=c_1z(k)/[1+c_sz(k)+c_3y(k)][1+c_4w(k)+(k+1)] z(k+1)=d_1z(k)/[1+d_2z(k)][1+d_3x(k)+d_4w(k)] 对于这个模型的线性化形式,详细讨论了控制松毛虫的暴发所需的条件及其生态学机制。  相似文献   

6.
在[1]中讨论了一般形式的非线性共生模型的稳定性,其中N_1(t)和N_2(t)分别表示 dN_1(t)/dt=f(N_1(t),N_2(t))N_1(t), dN_2(t)/dt=g(N_1(t),N_2(t))N_2(t) (1) t时刻种群1和2的个体总数。这里我们把这个模型按自然方式推广到带年龄结构的两种群共生模型 (?)+μp+f(N_1(t),N_2(t))P_i=0, p(0,t)=integral from n=0 to m_i b_i(r)p(r,t)dr, p_i(r,0)=p_0(r), N(t)=integral from n=0 to m_i p_i(r,t)dr,i=1,2。 (2)  相似文献   

7.
作者索引     
作  者期 (页码 )  阿其拉图 (Aqilatu) 6(687)*安树青 (AN Shu-Qing) 1(5 7) 安树青 (AN Shu-Qing) 6(64 1) 白克智 (BAI Ke-Zhi) 5 (5 3 2 ) 白坤甲 (BAI Kun-Jia) 5 (616)*白图格吉扎布 (BAI T.Jay ) 6(687)*白文明 (BAI Wen-Ming) 1(3 5 )*白文明 (BAI Wen-Ming) 4(4 3 1) 包国章 (BAO Guo-Zhang) 6(746) 贲桂英 (BEN Gui-Ying) 5 (5 2 0 ) 别之龙 (BIE Zhi-Long) 3 (3 2 5 )  BROWN Sandra 6(65 6)*蔡永立 (CAI Yong-L i) 1(90 ) 曹永生 (CAO Yong-Sheng) 3 (3 5 1) 陈 雄 (CHEN Xiong) 6(7…  相似文献   

8.
用均三甲基苯磺酰氯(M8)作缩合剂,合成了二个六脱氧核糖核苷酸(d-_(MMTr)G_p~(Bz)A_p~(Bz)C_p~(An)G_p~(Bz)A_p~(Bz)G_p~(Bz)和d-_(MMTr)C_p~(An)G_p~(Bz)A_p~(Bz)A_p~(Bz)C_p~(An))*,脱去保护基后经双向同系层析测定核苷酸排列顺序,完全符合实验设计要求(d-G_pA_pC_pG_pA_pG和d-T_pC_pG_pA_pA_pC)。上述二个带保护基的六脱氧核糖核苷酸合成的每一步,都是采用溶剂抽提方法分离的,大大简化了分离的步骤和缩短了分离的时间,便于脱氧寡核苷酸的大量制备。此法也适用于其他带保护基寡核苷酸的制备,不论其三苯甲基衍生物基团在5′端或3′端(例如d-_pG_p~(Bz)A_(ODMTr)~(Bz))。  相似文献   

9.
萹蓄的化学成分研究   总被引:20,自引:0,他引:20  
从药用植物蓄 (Polygonumaviculare)全草的丙酮提取物中分离鉴定了 10个化合物 ,经波谱学鉴定为 :山奈酚 (kaempferol) (1) ,槲皮素 (quercetin) (2 ) ,胡桃宁 (juglanin) (3) ,黄芪甙 (astragalin) (4) ,蓄甙 (avicularin) (5 ) ,槲皮甙 (quercetrin) (6 ) ,杨梅树皮甙 (myricitrin) (7) ,desmanthin 1(8) ,loliolide(9)和丁香脂素 (syringaresinol) (10 )。其中 ,化合物 (8) ,(9) ,(10 )为首次从该植物中分离得到。  相似文献   

10.
以江西杉木林红壤为研究对象,开展野外长期氮(N)、磷(P)添加控制试验,设置对照(CK)、N(50kg N hm~(-2)a~(-1))、P(50kg P hm~(-2)a~(-1))、NP(50kg N hm~(-2)a~(-1)+50kg P hm~(-2)a~(-1))处理,分析N、P添加对土壤碳矿化速率(C_(min))、氮矿化速率(N_(min))和相关的β-1,4-葡萄糖苷酶(βG)和β-1,4-N-乙酰葡糖氨糖苷酶(NAG)动力学参数的影响。结果表明:(1)N添加明显降低了C_(min)和N_(min),比CK分别减少了25%和18%;N添加减小了NAG的潜在最大酶活性(V_(max))、半饱和常数(K_m)、催化效率(V_(max)/K_m),但差异不显著(P0.05);N添加显著增加了βG的V_(max)、K_m,但对V_(max)/K_m有抑制作用。(2)P输入(P、NP)较CK使NAG的V_(max)、K_m减小26%—60%;NP同时添加明显提高βG和NAG的V_(max)/K_m(P0.05),但P输入(P、NP)对C_(min)和N_(min)影响不显著(P0.05)。(3)C_(min)与土壤溶解性有机碳正相关,N_(min)与pH显著正相关,与土壤NH_4~+-N、NO_3~--N显著负相关;βG和NAG的V_(max)/K_m均与NH_4~+-N、NO_3~--N负相关(P0.05),K_m均与NH_4~+-N、NO_3~--N正相关(P0.05)。βG的V_(max)与NH_4~+-N、NO_3~--N正相关(P0.05),NAG的V_(max)与有机碳、全氮、全磷、有效磷负相关(P0.05)。研究结果表明,在亚热带杉木人工林中,N添加降低土壤pH,增加土壤有效氮含量,抑制βG和NAG的V_(max)/K_m,对土壤C_(min)和N_(min)产生抑制作用;而NP添加增加土壤有效磷含量,增加土壤βG和NAG的V_(max)/K_m。  相似文献   

11.
报道广东新发现一种隶属于旋花科(Convolvulaceae)的危害森林的大型藤本植物―金钟藤(Merremiaboisiana),并对其形态进行描述。  相似文献   

12.
Ray Neyland 《Brittonia》2001,53(1):108-115
Cuscuta is a parasitic angiosperm that has been considered alternatively either as a genus within Convolvulaceae or as a monogeneric family in its own right. Although typically placed in the Solanales,Cuscuta has also been positioned within the Polemoniales. Extreme reduction of morphological and anatomical characters, as well as chloroplast genome reductions and rearrangements, has made the phylogenetic placement ofCuscuta uncertain. Analysis of 26S rDNA sequences suggests thatCuscuta is a derived member of Convolvulaceae. Molecular results are discussed in relation to the morphological and anatomical characters of autotrophic members of Convolvulaceae.  相似文献   

13.
Ergoline alkaloids (syn. ergot alkaloids) are constituents of clavicipitaceous fungi (Ascomycota) and of one particular dicotyledonous plant family, the Convolvulaceae. While the biology of fungal ergoline alkaloids is rather well understood, the evolutionary and biosynthetic origin of ergoline alkaloids within the family Convolvulaceae is unknown. To investigate the possible origin of ergoline alkaloids from a plant-associated fungus, 12 endophytic fungi and one epibiotic fungus were isolated from an ergoline alkaloid-containing Convolvulaceae plant, Ipomoea asarifolia Roem. & Schult. Phylogenetic trees constructed from 18S rDNA genes as well as internal transcribed spacer (ITS) revealed that the epibiotic fungus belongs to the family Clavicipitaceae (Ascomycota) whereas none of the endophytic fungi does. In vitro and in vivo cultivation on intact plants gave no evidence that the endophytic fungi are responsible for the accumulation of ergoline alkaloids in I. asarifolia whereas the epibiotic clavicipitaceous fungus very likely is equipped with the genetic material to synthesize these compounds. This fungus resisted in vitro and in vivo cultivation and is seed transmitted. Several observations strongly indicate that this plant-associated fungus and its hitherto unidentified relatives occurring on different Convolvulaceae plants are responsible for the isolated occurrence of ergoline alkaloids in Convolvulaceae. This is the first report of an ergot alkaloid producing clavicipitaceous fungus associated with a dicotyledonous plant.Data deposition: The sequences reported in this paper have been deposited in the GenBank (accession numbers are given in the text and in Fig. 3) Dedicated to Dr. Dr. h. c. mult. Albert Hofmann, the great pioneer of ergot research, on the occasion of his 100th birthday  相似文献   

14.
Three dihydroxynortropanes, 2alpha,7beta-dihydroxynortropane, 2alpha,3beta-dihydroxynortropane, and 3alpha,7beta-dihydroxynortropane, were isolated from calystegine-producing plants in the families Convolvulaceae and Solanaceae. 2alpha,7beta-Dihydroxynortropane was isolated from six species in the Convolvulaceae whereas only Calystegia soldanella contained it and 2alpha,3beta-dihydroxynortropane. Although neither of these were detectable in three species tested in the Solanaceae, 3alpha,7beta-dihydroxynortropane was, however, isolated from Duboisia leichhardtii.  相似文献   

15.
16.
Candidatus Liberibacter solanacearum” (Proteobacteria) is an important pathogen of solanaceous crops (Solanales: Solanaceae) in North America and New Zealand, and is the putative causal agent of zebra chip disease of potato. This phloem-limited pathogen is transmitted to potato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). While some plants in the Convolvulaceae (Solanales) are also known hosts for B. cockerelli, previous efforts to detect Liberibacter in Convolvulaceae have been unsuccessful. Moreover, studies to determine whether Liberibacter can be acquired from these plants by B. cockerelli are lacking. The goal of this study was to determine whether horizontal transmission of Liberibacter occurs among potato psyllids on two species of Convolvulaceae, sweet potato (Ipomoea batatas) and field bindweed (Convolvulus arvensis), which grows abundantly in potato growing regions of the United States. Results indicated that uninfected psyllids acquired Liberibacter from both I. batatas and C. arvensis if infected psyllids were present on plants concurrently with the uninfected psyllids. Uninfected psyllids did not acquire Liberibacter from plants if the infected psyllids were removed from the plants before the uninfected psyllids were allowed access. In contrast with previous reports, PCR did detect the presence of Liberibacter DNA in some plants. However, visible amplicons were faint and did not correspond with acquisition of the pathogen by uninfected psyllids. None of the plants exhibited disease symptoms. Results indicate that horizontal transmission of Liberibacter among potato psyllids can occur on Convolvulaceae, and that the association between Liberibacter and Convolvulaceae merits additional attention.  相似文献   

17.
BACKGROUND AND AIMS: Convolvulaceae is the most advanced plant family (asterid clade) that produces seeds with physical dormancy (water-impermeable seed coat). There are several different opinions about the nature of the specialized structure ('water gap') in the seed coat through which water initially enters seeds of Convolvulaceae, but none of them has been documented clearly. The primary aim of the study was to identify the water gap in seeds of Ipomoea lacunosa (Convolvulaceae) and to describe its morphology, anatomy and function. METHODS: Light microscopy, scanning electron microscopy, tissue-sectioning, dye-tracking and blocking experiments were used to describe the morphology, anatomy and function of the water gap in seeds of I. lacunosa. KEY RESULTS: Dormancy-breaking treatments caused slits to form around the two bulges on the seed coat adjacent to the hilum, and dye entered the seed only via the disrupted bulges. Bulge anatomy differs from that of the rest of the seed coat. Sclereid cells of the bulges are more compacted and elongated than those in the hilum pad and in the rest of the seed coat away from the bulges. CONCLUSIONS: The transition area between elongated and square-shaped sclereid cells is the place where the water gap opens. Morphology/anatomy of the water gap in Convolvulaceae differs from that of taxa in the other 11 angiosperm plant families that produce seeds with physical dormancy for which it has been described.  相似文献   

18.
Previous findings on structural rearrangements in the chloroplast genome of Cuscuta (dodder), the only parasitic genus in the morning-glory family, Convolvulaceae, were attributed to its parasitic life style, but without proper comparison to related nonparasitic members of the family. Before molecular evolutionary questions regarding genome evolution can be answered, the phylogenetic problems within the family need to be resolved. However, the phylogenetic position of parasitic angiosperms and their precise relationship to nonparasitic relatives are difficult to infer. Problems are encountered with both morphological and molecular evidence. Molecular data have been used in numerous studies to elucidate relationships of parasitic taxa, despite accelerated rates of sequence evolution. To address the question of the position of the genus Cuscuta within Convolvulaceae, we generated a new molecular data set consisting of mitochondrial (atpA) and nuclear (RPB2) genes, and analyzed these data together with an existing chloroplast data matrix (rbcL, atpB, trnL-F, and psbE-J), to which an additional chloroplast gene (rpl2) was added. This data set was analyzed with an array of phylogenetic methods, including Bayesian analysis, maximum likelihood, and maximum parsimony. Further exploration of data was done by using methods of phylogeny hypothesis testing. At least two nonparasitic lineages are shown to diverge within the Convolvulaceae before Cuscuta. However, the exact sister group of Cuscuta could not be ascertained, even though many alternatives were rejected with confidence. Caution is therefore warranted when interpreting the causes of molecular evolution in Cuscuta. Detailed comparisons with nonparasitic Convolvulaceae are necessary before firm conclusions can be reached regarding the effects of the parasitic mode of life on patterns of molecular evolution in Cuscuta.  相似文献   

19.
Chemotaxonomy and geographical distribution of tropane alkaloids   总被引:5,自引:0,他引:5  
Griffin WJ  Lin GD 《Phytochemistry》2000,53(6):623-637
This review illustrates the distribution of tropane alkaloids within the families Solanaceae, Erythroxylaceae, Proteaceae, Euphorbiaceae, Rhizophoraceae, Convolvulaceae and Cruciferae. Whereas tropane alkaloids are characteristic of the genera Datura, Brugmansia (tree datura) and Duboisia of the Solanaceae, the distribution is more widespread with novel tropane derivatives in families not traditionally associated with these bases. The chemical nature of more recently discovered water-soluble calystegines and the di- and trimeric forms from the Convolvulaceae (e.g. schizanthines from Schizanthus spp.), truxillines from Bolivian coca leaves and moonines of Erythroxylum moonii are highlighted. Where possible and appropriate, links between the phytochemistry and taxonomy are discussed.  相似文献   

20.
In Vitro Cellular & Developmental Biology - Plant - Ipomoea turbinata Lagasca and Segura (Purple Moonflower) belongs to the largest flowering genus Ipomoea in the Convolvulaceae family. Ipomoea...  相似文献   

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