杜鹃属植物区系的研究

已知世界杜鹃属(Rhododendron)植物约967种（种下分类等级未计算在内）。本文基于植物区系学的观点,讨论了属内8个亚属：常绿杜鹃亚属、杜鹃亚属、马银花亚属、映山红亚属、羊踯躅亚属、云间杜鹃亚属、纯白杜鹃亚属、异蕊杜鹃亚属的系统位置、分布式样。分析了系统发育和地理分布上的时间、空间关系。认为常绿杜鹃亚属和杜鹃亚属是在本属植物起源后的早期阶段就沿不同途径迁徙、繁衍的两个演化枝。自第三纪以来,它们的性状发展多样,种系高度分化。在现存类群中最具原始性状的亚属是常绿杜鹃亚属,这个亚属的云锦杜鹃亚组Subsect.Fortunea,耳叶杜鹃亚组Subsect.Auriculata 保持较多原始性状。种的分布遍及欧洲、北美洲、亚洲、大洋洲(有1种),东亚种类最多,马来西亚次之。中国-喜马拉雅地区既是多度中心又是多样化中心,马来西亚仅是多度中心。大多数种为地方特有性分布,特有现象十分突出,东亚和马来西亚的特有种共约862种,占种总数的89%以上中国有6个亚属(Candidastrum,Mumeazalea不产)约562种,其中特有种约405种。分析第三纪的化石记录,杜鹃属在全球分布的时间、地点,杜鹃属保持原始或古老性状的类群的现代适生地,认为中国西南至中国中部最有可能是杜鹃属植物的起源地,始祖类群起源的时间会是在晚白垩纪至早第三纪。讨论了杜鹃属在第三纪至第四纪向北半球北部的传布,向亚洲西南、亚洲东南和向东亚的传布以及向大洋洲的传布。从杜鹃属在全球传布的现象和途径,看来现代分布格局形成的原因取决于三方面的因素：时间和窨历史对植物繁衍、传播有着重要制约作用,并受制于植物种系自身具有的遗传性和对环境强烈变化的反应能力。     

类胡萝卜素产生菌№5205的分类鉴定

从江苏省如东沿海滩涂淤泥中分离到 1株产类胡萝卜素的诺卡氏菌形放线菌№ 5 2 0 5 ,其基丝形成横隔并断裂成短杆状 ,细胞壁化学组分IV型 ,糖类型A ,含枝菌酸 ,磷酸类脂类型PII(PE) ,甲基萘醌主要成分为MK 8(H4 ) ,属于诺卡氏菌属 (Nocardia)。经形态、生理生化、化学分类特性等鉴定为藤黄诺卡氏菌桔橙变种 (Nocardialuteavar.aurantiacan .var .)。     

展毛翠雀的花性状表型选择

传粉者的选择作用是花表型性状进化的重要驱动力, 解析选择作用的强度是理解花进化的关键。通过表型操控实验和表型选择研究能够分析花性状与其适合度的关系, 探究花性状的表型选择作用。为揭示花性状变化对雌性适合度的影响, 本研究处理展毛翠雀(Delphinium kamaonense var. glabrescens)花萼片大小, 并进行表型选择分析。结果表明: 人为减小展毛翠雀花萼片显著降低了传粉者的访花频率, 但是并没有影响种子产量(种子数和结籽率), 说明展毛翠雀花萼片的大小不影响种子产量, 可能主要吸引传粉昆虫输出花粉。通过雌性适合度(种子数量)估计表型选择梯度, 发现花萼片大小(长和宽)没有受到显著的直接选择梯度。但是, 花距长受到显著的线性选差和选择梯度, 表明花距的延长能够增加种子产量。本研究表明展毛翠雀花性状受到选择的作用, 但萼片和花距有不同的功能, 分别影响传粉者访问频率和种子产量。     

Effects of Ozone Fumigation on Photosynthesis and Membrane Permeability in Leaves of Spring Barley, Meadow Fescue, and Winter Rape

Seedlings of spring barley, meadow fescue, and winter rape were fumigated with 180 μg kg⁻¹ of ozone for 12 d, and effect of O₃ on photosynthesis and cell membrane permeability of fumigated plants was determined. Electrolyte leakage and chlorophyll fluorescence were measured after 6, 9, and 12 d of fumigation, while net photosynthetic rate (P _N) and stomatal conductance (g _s) were measured 9 d after the start of ozone exposure. O₃ treatment did not change membrane permeability in fescue and barley leaves, while in rape a significant decrease in ion leakage was noted within the whole experiment. O₃ did not change the photochemical efficiency of photosystem 2 (PS2), i.e., F_v/F_m, and the initial fluorescence (F₀). The values of half-rise time (t_1/2) from F₀ to maximal fluorescence (F_m) decreased in fescue and barley after 6 and 9 d of fumigation. P _N decreased significantly in ozonated plants, in the three species. The greatest decrease in P _N was observed in ozonated barley plants (17 % of the control). The ozone-induced decrease in P _N was due to the closure of stomata. Rape was more resistant to ozone than fescue or barley. Apparently, the rape plants show a large adaptation to ozone and prevent loss of membrane integrity leading to ion leakage. This revised version was published online in August 2006 with corrections to the Cover Date.     

光照强度对曼陀罗和紫花曼陀罗生长发育的影响

以曼陀罗(Datura stramonium)及其变种紫花曼陀罗(Datura stramonium var. tatual)为研究材料, 采用光照培养箱对盆栽苗进行5个光照强度的处理, 研究其生长发育、叶片解剖结构、叶片及茎色素含量对不同光照强度的响应。结果表明: (1)在试验设置的光照强度范围内, 增强光照强度有利于曼陀罗和紫花曼陀罗的发育及茎、叶生物量的积累; 13 000和18 000 lx两个光照强度下两供试曼陀罗长势最好; 同等光照强度下紫花曼陀罗的株高、基茎粗、叶片数目、茎叶生物量大于曼陀罗, 但差异性不显著。(2)两供试曼陀罗叶片厚度、栅栏组织厚度、海绵组织厚度及气孔密度、气孔指数均随着试验光照强度的增强而增加; 紫花曼陀罗气孔密度及气孔指数明显高于曼陀罗。(3)两供试曼陀罗叶片中叶绿素含量均随试验设置光照强度的增强呈先升后降的趋势; 随试验设置光照强度的增强, 两供试曼陀罗茎中叶绿素a、b及类胡萝卜素含量变化趋势不一致; 茎中花色素苷、类黄酮及总酚含量的变化情况是: 两供试曼陀罗均与光照强度呈正相关, 但紫花曼陀罗比曼陀罗含量高, 这也是紫花曼陀罗花、茎等器官呈紫色的物质基础, 加上气孔密度和气孔指数较大等特性, 使紫花曼陀罗较曼陀罗适应性更强。     

Phylogeography of var gene repertoires reveals fine‐scale geospatial clustering of Plasmodium falciparum populations in a highly endemic area

Plasmodium falciparum malaria is a major global health problem that is being targeted for progressive elimination. Knowledge of local disease transmission patterns in endemic countries is critical to these elimination efforts. To investigate fine‐scale patterns of malaria transmission, we have compared repertoires of rapidly evolving var genes in a highly endemic area. A total of 3680 high‐quality DBLα‐sequences were obtained from 68 P. falciparum isolates from ten villages spread over two distinct catchment areas on the north coast of Papua New Guinea (PNG). Modelling of the extent of var gene diversity in the two parasite populations predicts more than twice as many var gene alleles circulating within each catchment (Mugil = 906; Wosera = 1094) than previously recognized in PNG (Amele = 369). In addition, there were limited levels of var gene sharing between populations, consistent with local parasite population structure. Phylogeographic analyses demonstrate that while neutrally evolving microsatellite markers identified population structure only at the catchment level, var gene repertoires reveal further fine‐scale geospatial clustering of parasite isolates. The clustering of parasite isolates by village in Mugil, but not in Wosera was consistent with the physical and cultural isolation of the human populations in the two catchments. The study highlights the microheterogeneity of P. falciparum transmission in highly endemic areas and demonstrates the potential of var genes as markers of local patterns of parasite population structure.     

华重楼内生菌抗菌肽的分离纯化及其特性

摘要：【目的】华重楼内生菌PCE45具有较强的抗菌活性,本文将对PCE45产生的抗菌物质进行分离纯化和性质分析报道。【方法】PCE45发酵液经硫酸铵盐析、丙酮沉淀、SephadexG75柱、DE52纤维素柱和SephadexG25凝胶柱纯化分离得到抗菌肽PCP-1。【结果】稳定性测试表明该抗菌肽对蛋白酶不敏感,对高温、强酸、强碱有较好的耐受性,可造成稻瘟病菌菌丝畸形并抑制孢子萌发。抑菌谱表明该抗菌肽对玉米弯胞病菌等真菌和大肠杆菌等细菌有较强的抑菌效果。质谱测得其分子量为1058.3D。氨基酸组成分析表明该     

川西亚高山林线岷江冷杉和红杉对气候变化的响应

为揭示川西亚高山林线优势树种岷江冷杉（Abies fargesii var.faxoniana）和红杉（Larix potaninii）径向生长对气候变化的响应差异。通过树木年轮生态学的方法,研究了岷江冷杉和红杉径向生长与年均温的分异现象、生长衰退以及应对严重干旱事件的抵抗力和恢复力稳定性,并结合限制岷江冷杉和红杉径向生长的主要气候因素进行了分析。结果表明：（1）温度是限制林线岷江冷杉径向生长的主要气候因素,而限制红杉径向生长的主要气候因素是降水;（2）岷江冷杉的径向生长与年平均温度的变化趋势一致,红杉在20世纪90年代后径向生长呈现出下降的趋势,与年均温的升高出现分异;（3）1800-2019年间,岷江冷杉出现生长衰退2次,红杉出现生长衰退5次,相同的时间内,红杉的衰退频率高于岷江冷杉;（4）岷江冷杉对严重干旱事件的恢复力相比升温前有所增强,抵抗力相比升温前下降明显,红杉对严重干旱事件的抵抗力和恢复力相比升温前均呈现出下降的趋势。可为川西亚高山林线的植被动态变化预测和历史区域气候重建提供参考。     

中国水仙NtAP1基因的克隆与表达分析

采用RT-PCR和RACE技术,从中国水仙(Narcissus tazetta var.chinensis)幼嫩花芽中分离得到1个与花发育相关的MADS-box基因,将其命名为NtAP1(GenBank登录号为JN704304)。该基因全长1 155bp,含有1个762bp的开放阅读框,编码253个氨基酸。系统进化分析表明,该基因属于AP1-like基因。半定量RT-PCR分析表明,该基因在水仙品种‘金盏银台’和‘玉玲珑’的花瓣、副冠、雄蕊和雌蕊中均有表达,且在雌蕊中的表达量最高。研究认为,该实验分离出的NtAP1基因在‘玉玲珑’重瓣的形成过程中没有发挥重要的作用。     

Epidemiology of wheat take-all as influenced by soil pH and temporal changes in inorganic soil N

Summary Soil pH, NH ₄ ⁺ and NO ₃ ⁻ concentrations in soil, and take-all root rot of winter wheat grown in the field were measured concurrently from sowing to anthesis in order to relate disease development to liming and N fertilization practices. Experimental variables included soil pH (5.5 and 6.0) and three N sources (NH₄NO₃, (NH₄)₂SO₄, NH₄Cl) banded with the seed at sowing in factorial combination with the same three N sources topdressed in the spring. Take-all severity was increased by increasing soil pH and by fertilization with NO ₃ ⁻ . Disease severity on crown roots increased exponentially following spring N fertilization and was affected more by soil pH and N-form than was severity on seminal roots. Grain yield ranged from 4.70 Mgha⁻¹ with spring NH₄NO₃ at soil pH 6.0 to 7.65 Mgha⁻¹ with spring NH₄Cl at soil pH 5.5. Sixty-six percent of the variability in grain yield was explained by the number of take-all infected crown roots per tiller at anthesis. Oregon Agric. Exp. Stn. technical paper no. 7707.