松嫩平原碱化草甸朝鲜碱茅(Puccinellia chinampoensis)种群生殖分蘖株的生长规律

朝鲜碱茅(Puccinellia chinampoensis)是一种耐盐碱丛生型禾草,广泛分布于松嫩平原碱化草甸.采用每隔3d对朝鲜碱茅种群中处于抽穗初期的生殖分蘖株随机挂一次标签,于籽实蜡熟期同时进行大样本取样与测定的方法,定量分析了5次所标记的生殖分蘖株的数量性状的变化规律及生殖分蘖株的生长规律.结果表明,在朝鲜碱茅种群中,虽然抽穗时间只相隔3d,但生殖分蘖株的各数量性状均具有较大的表型可塑性,总的变化趋势是抽穗时间相隔越长,差异越大.其中,5次样本中的相邻平均花序生物量之间的差异均达到了显著水平.延长生殖生长16d,平均分蘖株高增加了23.16%,花序长增加了25.70%,分蘖株生物量增加了74.99%,花序生物量增加到2.63倍,生殖分配增加了93.25%.随着生殖生长时间的延长,朝鲜碱茅种群生殖分蘖株高、分蘖株生物量和花序生物量均呈指数增加,花序长和生殖分配呈直线增加,生殖生长比率呈先增加后降低的抛物线变化.不同时间进入生殖生长阶段的生殖分蘖株均具有相同的生长规律.其中,花序长均随分蘖株高的增加呈指数异速增长,花序生物量均随分蘖株生物量的增加呈直线同速增长.分蘖株的生殖生长越延长,对现实种群的贡献就越大,对未来种群的贡献更大.     

松嫩平原朝鲜碱茅无性系种群构件生物量结构及相关模型分析

从构件水平对松嫩平原碱化草甸朝鲜碱茅无性系种群各功能构件的生物量结构,各功能构件生物量与丛径之间的关系,以及各功能构件生物量之间的关系均建立相应的模型进行了定量分析。结果表明,在孕穗和果后营养两个生育期,朝鲜碱茅无性系种群各功能构件生物量及所占总生物量的比率具有相同的规律;各功能构件生物量与丛径之间的定量关系在孕穗期以直线函数模型相关性最大,在果后营养期以幂函数模型相关性最大;各功能构件生物量之间的定量关系除光合构件与支持构件在孕穗期以直线函数模型相关性最大外,其他各构件生物量之间在两个生长期均以幂函数模型相关性最大。     

松嫩平原碱化草甸朝鲜碱茅无性系冬眠构件的结构及生长分析

采用大样本随机挖取单个无性系的调查和测定方法,分析了松嫩平原碱化草甸朝鲜碱茅无性系冬眠构件的结构及其生长规律。结果表明,在生长季末期,朝鲜碱茅无性系冬眠构件是由冬眠苗和冬眠芽组成,其中,冬眠苗平均为72.27个±48.29个,冬眠芽为45.87个±26.27个。朝鲜碱茅无性系冬眠构件各组分具有相同的形成规律。冬眠苗数、冬眠芽数、冬眠构件总数均随着丛径、丛面积和亲株数量的增加呈幂函数异速生长。     

濒危植物朝鲜崖柏克隆种群可塑性及其对土壤条件的响应

朝鲜崖柏为长白山植物区系特有树种,是国家Ⅱ级重点保护的珍稀濒危植物。通过调查长白山区天然分布朝鲜崖柏种群的生境条件和克隆构件的形态学指标,分析了朝鲜崖柏克隆种群特征,并基于构件理论,采用灰色关联及通径分析方法,对种群构件与土壤因子的关系进行研究。结果表明:1)朝鲜崖柏克隆种群具有较强的表型可塑性,分布于暗针叶林下的朝鲜崖柏克隆种群分株间隔子长、地上扩张域、分株间距高于朝鲜崖柏纯林群落,种群构件变异性较高。2)朝鲜崖柏克隆生长格局介于密集型和游击型之间,具有快速克隆扩张能力和明显的斑块状。在土壤贫瘠的纯林群落内,种群更趋近于密集型分布;在土壤条件较好的暗针叶林下,更趋于游击型分布。3)朝鲜崖柏克隆种群生长对土壤异质性的响应具有特殊性,土壤水分是影响朝鲜崖柏种群扩张的最关键因子,土壤p H值、土壤腐殖酸、土壤速效磷、土壤速效钾是影响朝鲜崖柏克隆种群构件较重要的因子。4)土壤养分直接影响克隆植物构件特征及生态适应对策,各克隆分株构件受土壤养分影响的排序为速效磷速效钾有机质全氮。     

外来入侵植物牛膝菊种群构件生物量结构

牛膝菊原产南美洲,为沈阳地区爆发式入侵种．本文从构件水平研究了牛膝菊种群各构件生物量结构特征和各构件生物量间的关系模型,并进行了定量分析．结果表明,牛膝菊种群各构件生物量之间关系为茎〉叶〉花序〉根．各构件生物量在个体生物量中所占比率表现为茎〉叶〉根〉花序．牛膝菊种群茎生物量和叶生物量与植株高度、根生物量、花序生物量之间都呈显著的正相关关系,均可用幂函数模型较好地表达．     

外来入侵植物牛膝菊种群构件生物量结构

牛膝菊原产南美洲,为沈阳地区爆发式入侵种.本文从构件水平研究了牛膝菊种群各构件生物量结构特征和各构件生物量间的关系模型,并进行了定量分析.结果表明,牛膝菊种群各构件生物量之间关系为茎＞叶＞花序＞根.各构件生物量在个体生物量中所占比率表现为茎＞叶＞根＞花序.牛膝菊种群茎生物量和叶生物量与植株高度、根生物量、花序生物量之间都呈显著的正相关关系,均可用幂函数模型较好地表达.     

放牧退化群落中冷蒿种群生物量资源分配的变化

对放牧退化群落中冷蒿种群生物量及生物量资源分配的变化进行了研究.结果表明,在放牧干扰下,随着放牧退化程度的增加,冷蒿种群叶、茎、根的生物量及总生物量增加.其中根的重量增加幅度较大,但生殖构件(花序、果实)的生物量在轻度退化群落中增加,中度退化群落中迅速减少,重度退化群落中未发现生殖构件.随着放牧退化程度增加,冷蒿种群生物量的资源分配发生变化,对根的分配增加,对茎、叶的分配减少,根冠比增加;对无性繁殖的分配增加,对有性生殖的分配减少.在重度退化群落,冷蒿有性生殖严重受阻,繁殖格局发生变化.从资源分配的动态来看,随着放牧退化程度的增加,生长初期至盛期,冷蒿种群资源优先分配给地上部分,尤其是光合器官叶;而生长盛期至末期,资源优先分配给有性生殖或贮藏器官.繁殖格局的转变是冷蒿种群耐牧,在重度退化下成为建群种的关键.资源分配格局的时空变化,使生长、维持和繁殖等方面的分配达到和谐,是冷蒿种群在重度退化下成为建群种的物质基础.     

松嫩平原碱化草甸星星草种群营养养繁殖及有性生殖的数量特征

根据对星星草单优群落独立株丛的大样本取样和对正常花序随机取样的调查与测定,分析了松嫩平原碱化草甸星星草种群的营养繁殖及有性生殖特征,结果表明,星星种群诸营养繁殖数量性状之间有明显的规律性,丛植株数、丛地上生物量、丛生殖株数及丛生殖株重分别随丛径呈指数形式增加,星星草种群的圆锥花大多为９－１６个,花序上各节位上的小穗数量呈γ密度函数分布,随着节位的增高,各节位上的小花６娄量呈Ｌｏｇｉｓｔｉｃ曲线形式     

松嫩平原碱化草甸朝鲜碱茅种子散布机制的分析

采用顺序远离母株取样的方法,定量分析了松嫩平原碱化草甸朝鲜碱茅（Ｐｕｃｃｉｎｅｌｌｉａｃｈｉｎａｍ ｐｏｅｎｓｉｓ Ｏｈｗ ｉ）的种子散布机制。结果表明,在８个方向中仅西南方向表现为近母株散布距离,其它７个方向均表现为远母株散布距离的种子散布机制。经相关性分析,朝鲜碱茅向不同的方向散布的种子数量与种子散布时期顺风向的风速和风向频率呈正相关,反映了朝鲜碱茅是借助于风媒介实现了远母株距离扩展潜在生态位空间的种群对策。朝鲜碱茅向母株周围散布的种子呈连续分布格局的散布半径平均为１７５ ｃｍ 。     

缙云山2种禾草种群生殖配置的比较研究

利用样方法对生长于重庆缙云山不同生境条件下的2种禾草--白茅[Imperata cylindrica (L.) Beauv.]和淡竹叶(Lophatherum gracile Brongn.)的生物量配置格局进行了研究.结果表明,白茅种群在整个生长期内各构件生物量配置格局变化不大,其中对根状茎的配置比例最高,达到70.18%,有性生殖的生物量分配比例为4.51%,没有秆构件;淡竹叶种群在生长季内生物量配置格局发生较大变化,营养生长期、花期和黄熟期根构件的生物量分别占总生物量的77.33%、36.39%和48.66%,叶构件则为19.35%、45.42%和27.17%,有性生殖的生物量分配比例为11.11%.与白茅相比,淡竹叶种群秆构件明显.二者在生物量配置格局上存在显著差异,反映了二者对各自生活环境的适应特征.     

棕背树蜥不同组织三种同工酶之间的差异研究

文章采用垂直板聚丙烯酰胺凝胶电泳方法,研究了分布在广东韶关地区的棕背树蜥(CalotesemmaGray)的肝脏、肌肉、心脏、脑、生殖腺五种组织酯酶(EST)、淀粉酶(AMY)和过氧化氢酶(CAT)三种同工酶,研究结果,酯酶(EST)同工酶有两条共有的酶带,Rf8除了肝脏不具备外,心脏、肌肉、脑和性腺共有,体现肝脏的特异性,性腺酶带有明显的性别差异;淀粉酶(AMY)同工酶有一条共同酶带,肝脏酶带最为复杂,其次是生殖腺和雌体心脏,五种组织中有三种组织出现雌雄差异;过氧化氢酶(CAT)有两条共有的酶带,肝脏和生殖腺的酶带复杂,而且出现明显的性别差异性,心脏、肌肉和脑酶带相似,呈现不同组织的同源性.上述果表明三种同工酶在不同的组织表现出明显的同源性和差异性,雌雄个体间同一种酶表现出性别差异。     

Age-related aspects of male rats sexual behavior with different senescence rates

Social and sexual behavior of males Wistar and senescence-accelerated OXYS rats was studied. The experimental model excluding direct interaction between partners showed that the exploratory activity decreased with aging in rats of both strains, but social motivation didn't change. No interstrain differences in intensity of sexual motivation in the presence of an inaccessible receptive female were observed in 4-month rats. The level of sexual motivation of 12-month Wistar rats didn't differ from that of 4-month animals. However, in 12-month OXYS males, sexual motivation was decreased as compared to both 4- and 12-month Wistar rats. The same regularities were found under conditions of direct interaction with a partner. Behavioral changes in 12-month OXYS rats were considered as genetically determinate abnormality at the initial stage of sexual behavior, i.e., sexual motivation. The results suggest the accelerated senescence of the reproductive system of OXYS rats.     

Sex and vegetables in the Hippocratic gynaecological treatises

The compilers of the Hippocratic gynaecological treatises often recommend sexual intercourse as part of treatments for women's diseases. In addition, they often prescribe the use of ingredients that are obvious phallic symbols. This paper argues that the use of sexual therapy in the Hippocratic gynaecological treatises was more extended than previously considered. The Hippocratic sexual therapies involve a series of vegetable ingredients that were sexually connoted in antiquity, but have since lost their sexual connotations. In order to understand the sexual signification of products such as myrtle and barley, one must turn to other ancient texts, and most particularly to Attic comedies. These comedies serve here as a semiotic guide in decoding the Hippocratic gynaecological recipes. However, the sexual connotations attached to animal and vegetable ingredients in these two genres have deeper cultural and religious roots; both genres exploited the cultural material at their disposal.     

Subthalamic lesions eliminate sexual behavior in the male rat

Electrical stimulation of parts of the subthalamus and mesencephalon produces coordinated stepping movements, and for this reason these areas are sometimes referred to as the subthalamic and mesencephalic "locomotor" regions. In this study we contrast the sexual behavioral effect of electrolytic destruction of these two regions in the male rat. Lesions of the mesencephalic locomotor region had no significant effect on male sexual behavior. In contrast, subthalamic lesions centered on the caudal zona incerta just dorsal to the subthalamic nucleus eliminated sexual behavior in 6 of 15 males. The sexual behavior of the remaining males was affected to a lesser degree, for the most part in accord with the extent of destruction to this "critical zone." Subthalamic lesions produced no obvious impairment in locomotion, posture, limb use, muscle tone or sensorimotor orientation. Even so, the fact that electrical stimulation of the subthalamus elicits coordinated stepping suggests that the region is linked with systems directly concerned with movement and locomotion. These links could be particularly important in the process by which sexual motivation is translated into sexual behavior.     

Long-term paternity skew and the opportunity for selection in a mammal with reversed sexual size dimorphism

Most mammalian groups are characterized by male-biased sexual size dimorphism, in which size-dependent male-male competition and reproductive skew are tightly linked. By comparison, little is known about the opportunity for sexual selection in mammalian systems without male-biased dimorphism, where the traits under sexual selection might be less obvious. We examined 10 years of parentage data in a colony of greater horseshoe bats (Rhinolophus ferrumequinum) to determine the magnitude of male reproductive skew and the opportunity for sexual selection in a mammal in which females are the larger sex. Annual paternity success was weakly skewed but consistent patterns led to strong longitudinal paternity skew among breeders. Just three males accounted for a third of all paternity assignments, representing at least a fifth of all colony offspring born in a decade. Paternity success was in part determined by age but was not influenced by dispersal status. Our results show that paternity skew and the opportunity for sexual selection in a species with reversed sexual size dimorphism can approach levels reported for classical examples of species with polygyny and male-biased dimorphism, even where the traits under sexual selection are not known.     

Environmental heterogeneity,genotype-by-environment interactions and the reliability of sexual traits as indicators of mate quality

Exaggerated sexual displays are often supposed to indicate the indirect benefits females may receive from sexual reproduction with displaying males, but empirical evidence for positive relationships between the genetic quality and sexual trait quality is scant. The explanation for this might lie in the fact that mixing of reproductive individuals whose development has been influenced by genotype-by-environment interactions (GEIs) can blur the relationship between the individual male genetic quality and phenotype as perceived by females. Strong GEIs can generate an ecological crossover, where different genotypes are superior in environments that are separated either in space or time. Here, we use a stochastic simulation model to show that even a weak GEI, which does not generate an obvious ecological crossover, can neutralize or even reverse the relationship between genetic quality and sexual trait size in the presence of environmental heterogeneity during development. Our model highlights the importance of developmental selection in evolution of traits and allows us to predict the situations in which sexual displays might not be reliable indicators of genetic quality.     

新疆褐家鼠肥满度的初步研究

对在新疆北部干旱地区野外捕获765号褐家鼠标本进行了肥满度研究.结果表明,该鼠肥满度与年龄和栖息地无关,而有性别、季节和年度差异,肥满度变化与种群数量之间的相关程度均未达到显著水平,说明该鼠的肥满度不能作为预测其种群数量的主要指标.     

The Locally Optimal Method of Cyclic Alignment to Reveal Latent Periodicities in Genetic Texts: the NAD-binding Protein Sites

A program package has been developed to search for hidden tandem repeats of any specified type in the protein sequence databases. The applied algorithm of the locally optimal cyclic alignment is able to find subsequences possessing a certain profile-based periodicity type when no appreciable homology between periods is observed, as well as in the presence of arbitrary insertions/deletions. The profile can be adjusted to search for the periodicity types structurally and functionally important. The Swiss-Prot database has been analyzed to reveal the periodicities undetectable earlier that are caused by the secondary and super-secondary structure regularities of the NAD-binding sites. In particular, a significant periodicity of 24 aa was found to be characteristic of the absolute majority of domains possessing the Rossman (or Rossman-like) fold and displaying apparent regularity in their secondary structures, not being obvious at the primary structure level.     

Beyond sex allocation: the role of mating systems in sexual selection in parasitoid wasps

Despite the diverse array of mating systems and life histories which characterise the parasitic Hymenoptera, sexual selection and sexual conflict in this taxon have been somewhat overlooked. For instance, parasitoid mating systems have typically been studied in terms of how mating structure affects sex allocation. In the past decade, however, some studies have sought to address sexual selection in the parasitoid wasps more explicitly and found that, despite the lack of obvious secondary sexual traits, sexual selection has the potential to shape a range of aspects of parasitoid reproductive behaviour and ecology. Moreover, various characteristics fundamental to the parasitoid way of life may provide innovative new ways to investigate different processes of sexual selection. The overall aim of this review therefore is to re‐examine parasitoid biology with sexual selection in mind, for both parasitoid biologists and also researchers interested in sexual selection and the evolution of mating systems more generally. We will consider aspects of particular relevance that have already been well studied including local mating structure, sex allocation and sperm depletion. We go on to review what we already know about sexual selection in the parasitoid wasps and highlight areas which may prove fruitful for further investigation. In particular, sperm depletion and the costs of inbreeding under chromosomal sex determination provide novel opportunities for testing the role of direct and indirect benefits for the evolution of mate choice.     

Patterns of coexistence in sexual and asexual species of Cnemidophorus lizards

Summary The lizard genus Cnemidophorus (family Teiidae) contains sexual as well as parthenogenetic species. The theoretical two-fold fitness advantage of asexuality does not translate into any obvious distributional or numerical superiority of the parthenogenic species in the southwestern US and northern Mexico where their ranges overlap. I tested the prediction that the genetically diverse sexual species should have a higher between-individual niche width than a similar sympatric asexual species by studying the prey in stomach contents of sympatric and allopatric populations of C. tigris (sexual) and C. sonorae (asexual) in southern Arizona. The expectation proved true for niche breadths based on both prey length and prey taxa categories. The within-individual component of niche breadth was not different between species. Meaningful comparisons between species in sympatry and allopatry are confounded by the uncontrolled differences in the availability and diversity of food items between sites. Before the generality of these results can be assessed the study should be repeated in other areas where sexual and asexual species are syntopic and of similar body size.