Genetic architecture of yield and components of yield in mustard (Brassica juncea (L.) Czern & Coss.)

Summary The relative ability of cross- and self-pollen to achieve fertilisation in Brassica was studied by making double pollinations using cross-pollen carrying a dominant seedling marker gene. With simultaneous self- and crosspollination 12–40% self-seed was set, but when cross-pollen was applied to the stigma four hours before self-pollen, only 2–4% self-seed was obtained. In two plants to which cross-pollen was applied at various time intervals after self-pollen there was a tendency for the percentage of self-seed to increase as the time interval increased. In a third plant this trend was not apparent, probably because of a greater degree of self-incompatibility. The competitive advantage of the first pollen to arrive on the stigma is discussed in relation to the strength of the self-incompatibility and the sib problem in F₁ hybrid brassicas.     

大鼠实验性脾虚证胃粘膜内分泌细胞变化的免疫组织化学研究

用正常成年雄性Wistar大鼠53只,体重100～150g,分为正常对照组、实验性脾虚组、自然恢复组和四君子汤治疗组。取胃,固定于Bouin液。制成石蜡切片,进行(1)HE染色;(2)免疫组织化学染色,按Sternberger PAP法显示胃泌素细胞(G细胞)、生长抑素细胞(D细胞)和5-HT细胞。根据细胞的免疫反应程度,将细胞分为强阳性、中等阳性和弱阳性三级,每例动物计数三种细胞各1,000个,并计算各级细胞占的百分比;(3)从正常对照组,脾虚组随机选择各5例动物,对D细胞和G细胞进行显微分光光度计的定量测定;(4)由四组动物随机选择各5例,进行G细胞和D细胞密度及G/D细胞比值的测定。本文的观察表明:(1)脾虚组胃粘膜未见明显的组织学变化;(2)内分泌细胞:与对照组相比,脾虚组G细胞和5-HT细胞中,弱阳性细胞增多,表明分泌活动增强;D细胞弱阳性和中等阳性细胞减少,强阳性细胞增多,表明分泌释放减弱,合成增强。与自然恢复组比较,治疗组G细胞和D细胞的分泌活动接近于对照组;5-HT细胞无明显的恢复;(3)显微分光光度计的测定结果与光镜观察一致,脾虚组G细胞胃泌素反应物的含量低于对照组,D细胞内生长抑素反应物的含量高于对照组;(4)脾虚组G细胞密度低于对照组(P<0.01),D细胞密度略高于对照组,G/D细胞比值也低于对照组(P<0.01)。本文结果提示,脾虚证这些内分泌细胞的分泌活动出现异常,可能是导致消化功能紊乱的原因之一。经四君子汤治疗后,内分泌细胞的分泌活动接近于对照组,说明此药对脾虚证有一定的治疗作用。     

不同来源的肾综合征出血热病毒对Vero细胞的致病变作用

前文报道,肾综合征出血热病毒76-118株能使Vero细胞产生病变。本文报道76-118株和另11株不同来源的肾综合征出血热病毒(H537、A9、H5、R178、HB55、R22、Z10,沟3、L99、A16和J10)对Vero细胞的致病变作用(CPE )。其中除沟3株外,大部分毒株在感染Vero细胞后的第一代即可见明显的CPE。CPE的特点与76-118株相似,主要是感染细胞粘聚、融合,形成网状结构。CPE能被特异性抗HFRS病毒血清和型特异性单克隆抗体所中和抑制,但不能被特异性抗呼肠孤病毒Ⅲ型免疫血清所中和抑制。HFRS病毒对Vero细胞的致病变作用,对进一步研究HFRS病毒的某些生物学特性及实验方法等均有重要意义。     

肾综合征出血热病毒糖蛋白的提纯和鉴定

以感染肾综合征出血热病毒(HFRSV)的Vero E6细胞为材料,用免疫亲和层析结合制备聚丙烯酰胺凝胶电泳(PAGE)从感染细胞中提纯了HFRSV两种糖蛋白。先用免疫亲和层析从感染细胞的粗制抗原中获得含有四种蛋白的混合液,用[~3H]-氨基葡萄糖在感染细胞中标记病毒糖蛋白,观察到[~3H]-氨基葡萄糖只结合入78K和57K的病毒蛋白。再用制备SDS-PAGE从HFRSV混合液中提纯78K和57K两种蛋白。实验证明这两种糖蛋白均具中和抗原决定簇,57K的糖蛋白尚具血凝活性,初步鉴定表明这两种糖蛋白相当于文献报道的HFRSV G_1和G_2。     

Pollination and Breeding System of Vellozia squamata (Liliales: Velloziaceae): A Species of the Brazilian Cerrados

The pollination biology and breeding system of Vellozia squamata (Velloziaceae), a species of cerrado vegetation in Central Brazil, were studied. V. squamata is unusual in being pollinated by a few, generalist bee species despite having very large flowers, and having a distinctive pulsed flowering phenology. The species is self-incompatible but with a late-acting, post-fertilization rejection mechanism.     

Composition of Orchid Scents Attracting Euglossine Bees

Fragrance composition of flowers from 101 plant species, especially orchids, were analyzed. Several compounds, including allo-aromadendrene, β-bourbonene, α-copaene, α-cubebene, 1,2-dimethoxybenzene, 1,3,5-trimethoxybenzene, epoxygeranyl acetate, 7,11-epoxymegastigma-5(6)-en-9-one, two γ-lactones, germacradienol, germacrene D, humulene, methoxy-phenyl-ethyl acetate, myrcene epoxide, sabinene, styrene, and undecatriene were detected for the first time in orchids. Fragrance composition of flowers pollinated by male euglossine bee species (perfume flowers) of four plant families are compared and contrasted with those of orchid species with other pollination systems. Melittophilous, but highly specialized orchids, produce fragrances rich in different sesquiterpenes and other rare compounds. In the species that are exclusively pollinated by fragrance-collecting male euglossine bees, the fragrances are primary attractants that serve both as an attractant and as a reward. The unusually intensely smelling flowers mostly produce esters and monoterpenes. The fragrances of euglossophilous flowers of the three plant families investigated are composed of nearly the same sets of chemical compounds, suggesting convergent evolution. Typically, euglossophilous plant species produce large amounts of few fragrant substances while melittophilous species often produce rare compounds in small amounts.     

Increased Neopterin Levels in Brains of Patients with Human Immunodeficiency Virus Type 1 Infection

Postmortem levels of native neopterin (D-erythro-neopterin) were measured in cerebral cortical samples from 44 human immunodeficiency virus type 1-infected and eight uninfected, nonneurological control patients. Cerebral cortical gray and white matter neopterin levels for the controls ranged from 0.5 to 7.2 pmol/mg of protein in contrast to neopterin levels in brains of the virus-infected patients, which frequently were more than threefold and occasionally more than 30-fold higher than mean control levels. Cortical neopterin levels did not correlate with severity of the acquired immunodeficiency syndrome dementia complex, but subcortical levels correlated with the presence of active human immunodeficiency virus type 1 infection, as reflected by pathological evidence of multinucleated giant cell encephalitis. Evidence of opportunistic cytomegalovirus infections in approximately 25% of the human immunodeficiency virus type 1-infected patients was associated with enhanced levels of neopterin in frontal cortex.     

Reproductive ecology of dioecious Siparuna (Monimiaceae) in Ecuador–a case of gall midge pollination

The reproductive ecology of the dioecious genus Siparuna , belonging to the primitive family Monimiaceae, was investigated in Ecuador. Thirteen species were studied, and species growing at high altitudes (above 500 m) were compared with species growing at lower altitudes. The genus has specialized flowers pollinated by Cecidomyiidae (Asynapta sp. and other genera) that lay eggs chiefly in male flowers since these are more easily accessible than female flowers due to their morphology. Several traits ensure that pollen transfer is accomplished: 1. long flowering of individuals and single flowers; 2. specific floral morphology (unisexuality, landing platform, restricted pore) allowing the flowers to be visited by Cecidomyiidae seeking egg-laying sites, and 3. a low number of ovules that have to be pollinated in each flower. The low number of ovules per flower results in a high pollen-ovule (P/O) ratio even though pollen production in male flowers is only moderate.
High altitude species had larger flowers, higher pollen-ovule ratios, fewer ovules per female flower, and longer periods of anthesis. Gender differences were seen in the longer functionality of female flowers; the larger numbers of male flowers produced; and the average diameter at breast height (DBH) biased for one of the two sexes depending on the species investigated, with no clear trend in the size distributions of individuals of both sexes. Sex ratios departed significantly from unity both to male and female bias but usually were in favour of males. There were no general differences in the ratio of functional male to female flowers at the time of observation nor in the sizes of male and female flowers. The evolution of unisexual flowers in Siparuna can be explained as a result of the differential predation by larvae: unimportant in male flowers, destructive if occurring in female flowers.     

Pollination Ecology and Endemic Trends in Pedicularis bracteosa var. atrosanguinea Pennell & Thompson (Scrophulariaceae) in North America

Abstract Pedicularis bracteosa var. atrosanguinea occurs locally in association with P. racemosa or P. groenlandica in the Olympic Mountains in Washington. Other plant species, e.g., Polygonum bistortoides, Lupinus argenteus var. parviflorus and Valeriana sitchensis compete for space and bumblebee pollinators within the study area. Pollinator sharing, resulting from such competition, may increase the frequency of unvisited flowers of P. bracteosa var. atrosanguinea. P. bracteosa var. atrosanguinea , with blood purple nectariferous flowers, is presumed to lack intense reflections of blue spectral components from its corollas in attracting bumblebees compared to those of P. racemosa and P. groenlandica . Six species of bumblebees ( Bombus ) and cuckoo bees ( Psithyrus ) pollinate P. bracteosa var. atrosanguinea . Of these, Bombus mixtus and B. occidentalis occur in higher frequencies and are the major pollinators of P. bracteosa var. atrosanguinea . Queen and larger worker bumblebees pollinate nototribically as they probe for nectar, while smaller worker bumblebees pollinate sternotribically while scraping pollen from anthers deeply hidden in the dome-shaped galea. Corbicular pollen loads of bumblebees collected in the study area contain Pedicularis pollen alone/in combination of Polygonum, Valeriana, Lupinus, Erigeron and Bidens , or exclusively of Polygonum or Valeriana. P. bracteosa var. atrosanguinea does not suffer seriously from deficient pollination but seedlings resulting from pollinated flowers may be subjected to natural selection pressure exerted by colonial plant species for space. P. bracteosa var. atrosanguinea does not propagate asexually but resumes aerial growth seasonally from the self-same underground root stocks. If seedlings are under continuous selection pressure for lack of space, P. bracteosa var. atrosanguinea is presumed to regenerate primarily by perennial root stocks. This behavior may favor endemism in P. bracteosa var. atrosanguinea .