Stamen dimorphism in Rhododendron ferrugineum (Ericaceae): development and function

The function of stamen dimorphism in the breeding system of the alpine shrub Rhododendron ferrugineum was studied in two populations in the French Alps. This species has pentameric flowers with two whorls of stamens: an inner whorl of five long stamens and an outer whorl of short stamens. We studied the development of stamens from buds to mature flowers (measurement of the filament, anther, and style lengths at five successive phenological stages) and compared the size and position of reproductive organs at maturity in control and partially emasculated flowers (removal of long-level stamens) to determine whether the presence of long-level stamens constitutes a constraint for the development of the short-level ones. Stamen dimorphism can be observed early in stamen development, from the bud stage of the year prior to flowering. At this early stage, meiosis had already occurred. Emasculation of the long-level stamens induced the short-level ones to grow longer than in normal conditions. We also performed seven pollination treatments on ten randomly chosen individuals in each population, and the number of seeds following each treatment was recorded. Results from these treatments showed that R. ferrugineum produced spontaneous selfed seeds in the absence of pollinators. However, no seed was produced when short-level stamens were emasculated and pollinators excluded, suggesting that long-level stamens are not responsible for selfing in the absence of pollinators and that reproductive assurance is promoted by short-level stamens.     

Stamen development in the Ericaceae. I. Anther wall, microsporogenesis, inversion, and appendages

Development of the introrse, tetrasporangiate, and normally dorsifixed and poricidal stamens has been studied at the gross morphological and cellular level in ten species of Ericaceae. Microsporogenesis, followed in four species, is normal, with cytokinesis simultaneous, forming tetrahedral tetrads. The tricolp(or)ate pollen is shed as permanent tetrads with each segment two-celled except in Enkianthus in which pollen grains are three-celled monads. Anther-wall development is similar in all four species initially, but no regular pattern of wall development could be recognized thereafter. The tapetum, of parietal origin, is binucleate, glandular, and mainly uniseriate. Viscin threads occur with the tetrads in the three rhododendroid species. A well-developed endothecium appears only in Enkianthus.Soon after stamen initiation, anthers of nine species invert at the eventual filament-anther junction to become introrse; in Enkianthus inversion occurs close to anthesis. Microsporogenesis starts during early inversion; greater cell elongation on the abaxial side of the young anther completes inversion by the late sporogenous-tissue stage. In Erica and, to a lesser extent Calluna, inversion results from greater abaxial than adaxial increase in cell number and length just above the filament-anther junction. The single vascular strand reflects the degree of inversion. Stamens of six species are appendaged; three have only awns, two only spurs, while one has both. Appendages arise from residual meristems after inversion is completed (or almost so) in all except Enkianthus. Awns develop at what will be the apex at maturity of each anther half. Their length and orientation vary among species. Only in Vaccinium do the awns become hollow (tubules). Spurs, varying in length, shape, and size, arise on the abaxial side from the filament, connective, or thecae.     

The Morphology of Pollen Tetrads and Viscin Threads in Some Tertiary,Rhododendron-Like Ericaceae

The morphology of pollen tetrads and viscin threads is described in fossil Ericaceae pollen from various Eocene/Oligocene/Miocene localities in Europe (Germany, Austria), North America (eastern U.S.A.), and Asia (eastern China). The typical characters of the tetrad configuration, the exine ornamentation and sculpturing, and especially the viscin thread morphology are extremely similar to or even indistinguishable from that in extant members of Rhododendron. All these pollen morphological features strongly suggest that all the investigated material can be assigned to a modern taxon of the Ericaceae: either to Rhododendroideae or even to Rhododendron itself.     

The Stamen Patterns of Cultivated Plums

Stamen numbers were counted from flowers of cultivated plumvarieties (P. domestica), seedling clones from crosses betweenvarieties, and six other Prunus species. Varieties have a widerrange of stamen number than the presumed parental species, P.spinosa and P. cerasifera, and extend from 15.3 to 33.0 stamens. Counts on varietal and seedling clones indicate genetical controlof stamen pattern; clones have uniform patterns, but differfrom one another. Annual climatic variations affect stamen number,with varieties reacting differently. There are relationshipsbetween stamen numbers and some economic characters. Stamenpatterns may be helpful as an additional diagnostic characterand for the identification of bud-sports.     

杜鹃花族花粉形态及其系统学意义

利用光学显微镜和扫描电子显微镜对杜鹃属（Rhododendron L.）和仿杜鹃属（Menzie-sia Smith.)26种植物的花粉形态进行了观察和比较研究,其中大部分种为首次报道。杜鹃属和仿杜鹃属的花粉均为四合花粉,呈正四面体排列。四合体为圆角三角形,连接紧密。杜鹃属四合体平均直径在30.29-62.45μm之间,仿杜鹃属四合体直径为26.38-32.19μm,单粒花粉为球形或近球形,具三沟孔。在四合体上,相邻花粉粒上的沟相接,有时可见粘丝存在。杜鹃属和二鹃属花粉大小和花粉粒外壁纹饰均不同,具有明显的属间差异。在扫描电镜下,杜鹃属亚属内组（或亚组）之间花粉粒具有不同的外壁纹饰,可为分类学研究提供孢粉学方面的证据,具有重要的分类学意义。花粉分析在杜鹃属内不能作为分亚属的主要特征,但可用于某些种的分类学研究。     

不同年龄乳腺癌基因分型的对比研究

目的:对不同年龄乳腺癌患者基因分型的分布特点进行分析,为乳腺癌的治疗和预后判断提供参考依据。方法:回顾性分析青年、中年、老年乳腺癌患者的临床资料,对其基因分型分布进行对比分析。结果:不同年龄(≤40岁、40岁-60岁、≥60岁)乳腺癌的基因分型分布比较有显著性差异,存在统计学意义(P0.05),年轻乳腺癌患者中≤35岁与35-40岁患者的基因分型的分布也存在显著性差异(P0.05)。结论:不同年龄乳腺癌人群的基因分型不同,需结合其他临床和病理指标综合评估患者病情及预后;老年乳腺癌患者基因分型的分布并不乐观,需强调早期诊断和治疗。     

The Specificity Of Processes Of Motivational Conditioning In The Human Mind

The methodological principle of the objectification of needs, which in activity theory explains the ontological development of motivation (Leont'ev, 1975), is in need of concrete psychological development to ascertain what influences and mental processes give rise to such objectification. In terms of biological motivation, this question is made easier by the existence of a detailed system of data, accumulated in conditioning studies, concerning the acquisition of the capacity to activate a person by neutral stimuli. A psychological interpretation of these data purports to explain the fact that the conditioned response phenomenon indicates not only a redirecting of unconditioned responses toward new stimuli but also the genesis, in response to this stimulus, of subjective relations orienting the person toward influences relevant to his needs. Such an interpretation therefore helps to concretize the concept of the objectification of biological needs (Vilyunas, 1986. Pp. 154-74).