植物有性生殖过程中的细胞程序性死亡

细胞程序性死亡(pmgrammed cell death,PCD)已成为当前生物学的研究热点之一,PCD是植物发育过程中的一种普遍现象,植物生殖器官中一些细胞的死亡对植物有性生殖具有重要作用,有性生殖过程中的植物细胞程序性死亡具有细胞类型特异性,即在特定时期,只有特定的细胞才会发生程序性死亡,本文介绍了植物有性生殖过程中各种类型的细胞在特定时期所发生的程序性死亡的形态和生化特征,这些PCD类型包括单性花的形成、性别决定、大小孢子的退化、花粉发育及绒毡层的解体、雌雄配子体的发育、花粉管的生长、胚胎发育过程中胚柄、胚乳以及糊粉层的消失等等。     

认识的信息加工过程对通信过程的超越：信息的有性繁殖刍议

笔者把人的认识过程理解为一种信息加工过程,但是这种认识的信息加工过程远此一般通信过程要复杂和高级得多。在认识的信息加工过程中内含着一种特殊的信息加工方式——信息的“有性繁殖”,这种特殊的信息加工方式对认识的发生、发展、进化起着至关重要的作用。     

Hormonal control of pheromone responsiveness in the male black cutwormAgrotis ipsilon

In Lepidoptera, reproduction is linked to chemical communication between conspecific partners. When exposed to the female sex pheromone, males respond by exhibiting typical sexual behaviour which leads to mating. Here we show that presence of the juvenile hormone producing gland (corpora allata) of the male black cutworm,Agrotis ipsilon, is necessary for pheromone responsiveness. Allatectomized males do not show any sexual behaviour, although their antennal olfactory system is functional. Allatectomized males implanted with active corpora allata recover full pheromone receptivity. It is suggested that reproductive processes are synchronized in males and females through endocrine control; timing of the mating activity could serve as an adaptive strategy linked to the migratory behaviour of this species.     

中学生数学能力方面性别差异的调查研究

通过调查问卷和能力测试等方法,探讨了中学生在教学能力上的性别差异,分析了造成这种差异的原因,并从心理、社会和教育等方面提出了两性补充教育、改进教学方法和提高教师素质等缩小差异的具体措施和建议。     

现实原则的女性思考及其意义——评《我承认我最怕天黑》

《我承认我最怕天黑》通过对女主人公与三个男人在意识与现实两个层面性关系的描写,阐明了女性所遵循的现实原则。在以无过错为基本内容的现实原则的指导下,女性产生了性的迷茫,这既是女性现实生活性状态的一种真实写照,也反衬出当今文学创作中性的泛化描写过于夸张甚至虚妄。     

新时期女性文学性别意识探微——李宇春走红现象的反思

面对强大的男权社会的对垒。女性性别意识在历史和残酷现实竞争中不经意蜕变雄化，性别迷失。文学是人学，在新时期女性文学的影象中，女性文学在女性主义高涨的浪潮里，同样返照着女性自救征途上无法避免的男性化倾向。其现状源于沉重的“第二性”历史和四面楚歌的残酷现实，而女性文学真正意义上的解放必然是摆脱男权意识和男性性别参照，认识自我，认识人类已有的文明和秩序，寻求与外部世界抗争和合作的勇气，寻找女性真正意义上的生命本体回归。     

当代大学生性心理现状及其健康教育

采用问卷形式对 10 0 0名在校大学生所存在的性心理障碍问题进行调查 .发现不同男女大学生存在的性心理障碍己到了不容乐观的程度 .性心理障碍带来的心理、生理上的失调 ,己严重影响了大学生的学习和生活 提出为大学生们克服性心理障碍的对策 .     

Sexual difference in gonadal development of embryonic chickens after treatment of polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are ubiquitous, persistent and lipophilic environmental endocrine disrupters that can be biomagnified in human and animals including birds and thus to affect reproductive functions. Poultry meat and eggs contain a great deal of fat and possibly concentrate higher PCBs and other environmental contaminants such as dichlorodiphenyl-trichloroethane (DDT). In order to identify the adverse effects of PCBs and possible sexual difference on chicken gonadal development, Aroclor 1254 was injected into fertilized Hyline chicken eggs before incubation. Four groups of eggs received yolk injection of either peanut oil as control, 1, 10 or 100 mg/egg of Aroclor 1254 as treatment group, respectively. After hatching the gonads were removed for histological examination. Testicular structure was apparently changed and exhibited dramatic decrease in area of the transverse sections (1 mg/egg, P＜0.01; 10 and 100 mg/egg, P＜0.001), diameter (10 and 100 mg/egg, P＜0.05) and relative area of the testicular tubules (10 mg/egg, P＜0.05; 100 mg/egg, P＜0.01). Most testicular tubules of the highest dose group degenerated and even disappeared. The differentiation of germ cells was retarded in all groups treated with Aroclor 1254. Some germ cells were irregular in shape, with vacuolated cytoplasm and hyperchromatism nucleus (pyknosis) in 1 and 10 mg/egg groups and almost all germ cells in 100 mg/egg group. In contrast, the area of the left ovarian transverse sections increased dramatically (10 and 100 mg/egg,P＜0.001), the ovarian cortex manifested a significant increment in thickness (1, 10 and 100 mg/egg, P＜0.001) and a higher number of oocytes was observed (1, 10 and 100 mg/egg, P＜0.001) in the female chickens treated with Aroclor 1254 compared with the control group. A few oocytes with vacuolated cytoplasm and hyperchromatic nucleus were also observed in ovarian cortex after PCBs exposure. These results showed that PCBs interfered with gonadal development with a sex-specific pattern and retarded differentiation of spermatogonia into spermatocytes but accelerated differentiation of oogonia into oocytes in the embryonic chickens.     

Mating behaviour in the bees,Dieunomia heteropoda and Nomia tetrazonata,with a review of courtship in Nomiinae (Hymenoptera: Halictidae)

Males of many bees in the subfamily Nomiinae (Halictidae) have numerous secondary sexual characters, which provide much systematic information. Similarly, the use of these structures by males during sexual behaviour may provide useful characters, but the courtship and copulatory behaviour of most of these bees is not known. Structures and behaviour used for courtship and mating are described for two species of nomiine bees, Dieunomia heteropoda and Nomia tetrazonata, along with brief observations of mating in a parasitic bee, Triepeolus verbesinae (Apidae: Nomadinae). A review of mating behaviour within the Nomiinae shows no obvious phyletic patterns, based upon present limited knowledge. The species-specific nature of the male secondary sexual characters suggests they may have evolved in the context of sexual selection, but behavioural data from populations of additional species are needed to evaluate the hypothesis adequately.     

Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

While expulsion of male ejaculates by the females after copulation has been reported for various animal groups, expulsion followed by consumption of the expelled ejaculate is a rare behaviour outside spermatophylax-producing orthopterans. Among Diptera, this behaviour has been reported for a few species of Piophilidae, Empididae and Ulidiidae. Here we report on its occurrence among Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae). We also attempt to characterize the mating system of E. eluta in order to facilitate future hypothesis testing to understand the behavioural factors leading to the evolution of this peculiar behaviour. For this, courtship sequences, copulation duration, frequency of ejaculate expulsion and subsequent consumption, and latency to ejaculate expulsion for both E. eluta and E. mazorca were recorded. The time of sexual maturation, the time window of sexual receptivity during the day, and the mating frequency and variance in mating success for males and females (degree of polygamy) were determined for E. eluta. Both E. eluta and E. mazorca males engaged in elaborate courtship sequences involving visual and tactile displays before copulation. Females of both species almost invariably expelled and consumed ejaculates after copulation. Female E. eluta, required a 6- to 9-day period feeding on protein and sugar before becoming sexually receptive. Reproductive activity occurred continuously over the day with an early morning and late afternoon peak. Both males and females could mate multiply, with multiple partners over a 2-h observational period. Sexual network analysis revealed that some males and females had greater mating success than others. Ejaculate consumption appears to be widespread in the genus Euxesta. It is possible that females obtain nutrients from this behaviour while exerting some control over egg fertilization.