Phylogenetic analysis of sexual dimorphism and eye-span allometry in stalk-eyed flies (Diopsidae)

Eye stalks and their scaling relationship with body size are important features in the mating system of many diopsid species, and sexual selection is a critical force influencing the evolution of this exaggerated morphology. Interspecific variation in eye span suggests there has been significant evolutionary change in this trait, but a robust phylogenetic hypothesis is required to determine its rate and direction of change. In this study, the pattern of morphological evolution of eye span is assessed in a phylogenetic framework with respect to its function in the sexual system of these flies. Specifically, we examine within the family Diopsidae the pattern of increase and decrease in sexual dimorphism, the morphological coevolution of eye span between males and females, and the evolutionary flexibility of eye-span allometry. Based on several different methods for reconstructing morphological change, results suggest a general pattern of evolutionary flexibility, particularly for eye-span allometry. Sexual dimorphism in eye span has evolved independently at least four times in the family and this trait also has undergone several reductions within the genus Diasemopsis. Despite most species being dimorphic, there is a strong phylogenetic correlation between males and females for mean eye span. The coevolution between the sexes for eye-span allometry, however, is significantly weaker. Overall, eye-span allometry exhibits significantly more change on the phylogeny than the other morphological traits. The evolutionary pattern in eye-span allometry is caused primarily by changes in eye-span variance. Therefore, this pattern is consistent with recent models that predict a strong relationship between sexual selection and the variance of ornamental traits and highlights the significance of eye-span allometry in intersexual and intrasexual signaling.     

The GmCLC1 protein from soybean functions as a chloride ion transporter

Soil salinization is a global issue that hampers agricultural production. Chloride is one of the prominent anions on saline land that cause toxicity to the plant. We previously identified the GmCLC1 gene from soybean (Glycine max) that encodes a putative tonoplast-localized chloride transporter. In this study, using electrophysiological analysis, we demonstrated the chloride transport function of GmCLC1. Interestingly, this chloride transport activity is pH dependent, suggesting that GmCLC1 is probably a chloride/proton antiporter. When the cDNA of GmCLC1 was expressed in tobacco BY-2 cells under the control of a constitutive promoter, the protective effect against salinity stress in transgenic tobacco BY-2 cells was also found to be pH sensitive. In the native host soybean, the expression of GmCLC1 gene is regulated by pH. All these findings support the notion that the function of GmCLC1 is regulated by pH.     

The distribution of the effects of genes affecting quantitative traits in livestock

Meta-analysis of information from quantitative trait loci (QTL) mapping experiments was used to derive distributions of the effects of genes affecting quantitative traits. The two limitations of such information, that QTL effects as reported include experimental error, and that mapping experiments can only detect QTL above a certain size, were accounted for. Data from pig and dairy mapping experiments were used. Gamma distributions of QTL effects were fitted with maximum likelihood. The derived distributions were moderately leptokurtic, consistent with many genes of small effect and few of large effect. Seventeen percent and 35% of the leading QTL explained 90% of the genetic variance for the dairy and pig distributions respectively. The number of segregating genes affecting a quantitative trait in dairy populations was predicted assuming genes affecting a quantitative trait were neutral with respect to fitness. Between 50 and 100 genes were predicted, depending on the effective population size assumed. As data for the analysis included no QTL of small effect, the ability to estimate the number of QTL of small effect must inevitably be weak. It may be that there are more QTL of small effect than predicted by our gamma distributions. Nevertheless, the distributions have important implications for QTL mapping experiments and Marker Assisted Selection (MAS). Powerful mapping experiments, able to detect QTL of 0.1σ_p, will be required to detect enough QTL to explain 90% the genetic variance for a quantitative trait.     

贵州省安龙县狂犬病的流行病学研究

为了探讨局部地区暴发流行的因素,对2004年与2005年间在贵州省安龙县及其周边发生的人间狂犬病进行个案调查,用直接免疫荧光法检测犬脑组织中的狂犬病毒抗原,用RT-PCR法扩增G基因片段,测定核苷酸序列并构建系统发生树进行遗传特征分析.自1994-2003年安龙县报告无人间狂犬病疫情,但于2004与2005年分别报告44例与27例人狂犬病.71例狂犬病患者中68人被犬所伤,3人被猫所伤.在有完整记录的69例患者中,潜伏期平均为47.5d(10～282),13例狂犬病患者的潜伏期≤15d(18.84%);32例的潜伏期≤30d(46.38%),尤其是在2004年的患者中,潜伏期≤20d的病例有13例,占30%.2005年在疫点周围采集的85只犬脑组织中,5只犬脑组织狂犬病毒抗原阳性,阳性率为5.88%.A13株与A48株病毒之间的G基因核苷酸序列同源性为86.5%,与已报道病毒株比较发现,A13株与广西分离株有最高的同源性,而A48株却与印度尼西亚分离株SN01-23的同源性最高.比较分析两株病毒G基因编码的氨基酸序列,发现包括GⅠ、GⅡ,以及GⅢ抗原位点内的区间,A13与A48分别有19和28个氨基酸位点发生了氨基酸的替代.用全G基因核苷酸序列进行系统分析发现,两株毒株全为Ⅰ型狂犬病毒.结果表明引起安龙县的狂犬病流行的病毒不是新型狂犬病毒,犬饲养量大与病毒携带率高是狂犬病发病暴发流行的直接原因.     

Adaptive phenotypic plasticity and genetics of larval life histories in two Rana temporaria populations

Phenotypic plasticity provides means for adapting to environmental unpredictability. In terms of accelerated development in the face of pond-drying risk, phenotypic plasticity has been demonstrated in many amphibian species, but two issues of evolutionary interest remain unexplored. First, the heritable basis of plastic responses is poorly established. Second, it is not known whether interpopulational differences in capacity to respond to pond-drying risk exist, although such differences, when matched with differences in desiccation risk would provide strong evidence for local adaptation. We investigated sources of within- and among-population variation in plastic responses to simulated pond-drying risk (three desiccation treatments) in two Rana temporaria populations originating from contrasting environments: (1) high desiccation risk with weak seasonal time constraint (southern population); and (2) low desiccation risk with severe seasonal time constraint (northern population). The larvae originating from the environment with high desiccation risk responded adaptively to the fast decreasing water treatment by accelerating their development and metamorphosing earlier, but this was not the case in the larvae originating from the environment with low desiccation risk. In both populations, metamorphic size was smaller in the high-desiccation-risk treatment, but the effect was larger in the southern population. Significant additive genetic variation in development rate was found in the northern and was nearly significant in the southern population, but there was no evidence for genetic variation in plasticity for development rates in either of the populations. No genetic variation for plasticity was found either in size at metamorphosis or growth rate. All metamorphic traits were heritable, and additive genetic variances were generally somewhat higher in the southern population, although significantly so in only one trait. Dominance variances were also significant in three of four traits, but the populations did not differ. Maternal effects in metamorphic traits were generally weak in both populations. Within-environment phenotypic correlations between larval period and metamorphic size were positive and genetic correlations negative in both populations. These results suggest that adaptive phenotypic plasticity is not a species-specific fixed trait, but evolution of interpopulational differences in plastic responses are possible, although heritability of plasticity appears to be low. The lack of adaptive response to desiccation risk in northern larvae is consistent with the interpretation that selection imposed by shorter growing season has favored rapid development in north (approximately 8% faster development in north as compared to south) or a minimum metamorphic size at the expense of phenotypic plasticity.     

土壤干旱胁迫对毛鸡骨草幼苗生长及某些生理特性的影响

以毛鸡骨草幼苗为试验材料,测定毛鸡骨草在不同水分条件下的生长状况和相关的生理生化指标,结果表明:随着干旱胁迫的增加,毛鸡骨草幼苗的株高、茎粗、复叶长等呈递减趋势,根直径、须根数呈递增趋势;根、叶片脯氨酸含量和叶片可溶性糖的含量均呈先降低再上升的趋势,水势随干旱胁迫的加剧呈先上升后降低的趋势,根系活力随干旱胁迫的加剧呈递减趋势。但是,在严重干旱胁迫下,各生长指标的增长均受到明显的抑制。     

数学形态学在昆虫分类学上的应用研究.Ⅰ.在目级阶元上的应用研究

根据昆虫图像,对半翅目（Hemiptera）、鳞翅目（Lepidoptera）、鞘翅目（Coleoptera）的34种昆虫提取形状参数、叶状性、球状性等7项数学形态特征进行了统计分析,从而论证了各项数学形态特征在目级昆虫分类阶元上作为分类特征的可行性和可靠性,并从数学形态学角度对所涉及到的同阶元昆虫类群的亲缘关系做了描述。结果表明,在作为目级阶元分类特征时,各项特征的可靠性依次为：(似圆度、偏心率、亮斑数)＞(叶状性、球状性、圆形性)＞形状参数。由这些特征的差异显著性可知,从数学形态特征角度讲,3个目的亲缘关系远近大小依次为：半翅目与鞘翅目＞半翅目与鳞翅目＞鳞翅目与鞘翅目。     

1959—2006年长白山地区降水序列的多时间尺度分析

基于长白山地区松江、东岗、长白、和龙、临江和天池6个气象站1959—2006年的月均降水量和年降水量数据,采用Morlet小波分析方法,对1959—2006年长白山地区植被生长季（5—9月）降水量、降雪季（11月至次年4月）降水量和年降水量序列进行多尺度特征分析,并运用Daubechies小波系中的db5小波对各降水序列进行不同层次的分解和低频重构,对重构序列进行了趋势识别和分析.结果表明：研究期间,长白山地区植被生长季降水量存在3～6 a、10～13 a和24～30 a的特征周期;降雪季降水量存在1～2 a、5～7 a和17～20 a的特征周期;年降水存在8～10 a、16～20 a、25～30 a的特征周期;研究区年降水量序列呈现整体下降的趋势.     

草坪蒸散研究进展

草坪蒸散量是指导草坪合理灌溉的重要指标。自20世纪中叶以来,以节水为目的的草坪蒸散研究越来越受到人们的重视。草坪蒸散研究的内容主要包括相互关联的3个方面：草坪蒸散率的测定与比较,草坪蒸散机制的研究和草坪节水灌溉的研究。草坪蒸散率在不同草种间存在不同程度的差异。暖季型草坪草和冷季型草坪草相比普遍具有较低的草坪蒸散率。暖季型草坪草的夏季日平均最大蒸散率为3.0-9.0mm,而冷季型草坪草的为3.6-12.6mm。密度大,生长缓慢的杂交狗牙根、结缕草、野牛草和假俭草的耗水量很低,细羊茅的耗水量中等,而草地早熟禾、高羊茅、1年生早熟禾和匍匐剪股颖的耗水量很大。同种草坪草的不同品种的草坪蒸散率存在差异。有些草种内品种间差异的程度高达64％,不亚于种间。冷季型草坪草品种的蒸散率与留茬量显著相关,但环境因子对品种的蒸散率影响很大,品种的蒸散特性不稳定。与冷季型草坪草相比,暖季型草坪草的种内品种间蒸散率的差异和谐较小。草坪的冠层是草坪蒸散的一个主要外部条件,具有较低蒸散率的草坪往往具备高冠层阻力和低叶面积。土壤水分不受限制时,不同的暖季型草坪草种间的草坪蒸散率与叶片背面的气孔密度显著负相关。但在种内品种间没有表现出相关性。冷季型草坪草种间和种内的叶片气孔数目和草坪的蒸散率不相关。草坪的作物系数是确定最适灌溉量的关键参数,线性梯度灌溉系统比小型蒸渗仪提供的草坪作物系数更接近于实际。当草坪的质量维持在可接受的水平时,以彭曼公式推测的苜蓿的潜在蒸散量为参照蒸散量,高羊茅草坪的作物系数为0.60-0.80,草地早熟禾草坪的作物系数为0.50-0.80。基于草坪冠层温度的作物水分胁迫系数（CWSI）是确定灌溉时机的比较合理的指标。CWSI在不同的季节和不同的草种间表现不稳定,并且这种方法的节水效果也表现不一,还处于发展阶段。草坪蒸散的研究在我国几乎处于空白状态,开展我国的草坪蒸散研究,寻求适合的草坪节水途径已势在必行。     

关于卤虫种间竞争的探讨

天津塘沽盐场的产盐期在春季,但塘沽卤虫到７、８月份才能形成较大的种群。鉴于卤虫种群对春盐的产量和质量的作用,应考虑引进某一耐低温高盐的卤虫品系以配合春盐生产。经实验证明［３］,中国张北卤虫和美国旧金山卤虫具备此种条件。本实验进一步研究了张北卤虫和塘沽...