Chronological age and reservoir characteristics as predictors of trait composition in Neotropical reservoir fish assemblages

One of the main impacts on aquatic environments is the alteration of flow regime, usually caused by dam construction. This impact changes the dynamics and functioning of the environment. We aimed to evaluate changes in the composition of functional traits of fish assemblages from 29 reservoirs of different chronological ages. We assessed if there were any alterations in trophic state of these reservoirs according to their ages (chronological variable). Then, we evaluated the relationship between functional traits and environmental/chronological variables. Results showed that reservoir age is a predictor of fish assemblage functional traits composition. In older reservoirs, there was a predominance of omnivorous species, with multiple spawning and parental care. However, herbivorous species, with total spawning and medium size, had their abundance reduced. Also, it was possible to identify the influence of depth and water retention time on the composition of functional traits. By showing that although age has an influence on composition, the intrinsic characteristics of each reservoir are very important in evaluating the impacts of these projects. Therefore, the findings presented provide insights into what may happen to functional traits of fish assemblages with ageing of reservoirs.     

Androgen-induced neural plasticity and the regulation of electric-social behavior in the brown ghost knifefish: current status and future directions

The weakly electric brown ghost knifefish (Apteronotus leptorhynchus) modulates its electric organ discharge to produce intraspecific communication signals called chirps. Although males and females are known to produce chirps during courtship and spawning, they show clear sex differences in their propensity to chirp in response to artificial electrosensory stimuli; males consistently chirp, whereas females generally do not. This species also shows prominent sex differences in substance P-like immunoreactivity (SPl-ir) in brain. Males, but not females, have intense SPl-ir in a number of forebrain regions known to control reproductive functions, including the prepacemaker nucleus (PPn), the command center for chirping behavior. However, androgen treatment enhances both chirping behavior and brain SPl-ir in females. In addition, chirps produced by androgen-treated females are similar to those reported to occur during spawning. The results suggest that steroid-induced neural plasticity of SPl input to the PPn may play an important role in modulating female chirping activity. However, potential problems with this interpretation are discussed.     

岷江百合天然群体的表型多样性

 以岷江百合(Lilium regale Wilson)的7个天然群体为研究对象,对其株高、花瓣长、叶片数、花朵数、叶片长和叶片宽等6个表型性状进行多样性分析。结果表明：岷江百合表型性状在群体间存在广泛变异,6个性状群体间的F值为4.878～34.915,达显著或极显著水平;群体内只有叶片长和叶片宽达极显著水平,其他4个性状均不显著。6个性状的平均表型分化系数(VST)为61.5%,群体间变异（26.2%）大于群体内变异（20.0%）,说明群体间变异是百合表型性状的主要变异来源。岷江百合表型性状与地理因子的相关分析表明：株高、花朵数和叶宽与纬度成显著正相关,而其它性状与地理因子的相关性均不显著。利用群体间欧氏距离进行的UPGMA聚类分析结果表明,7个岷江百合天然群体可以划分为两类,说明性状的表型特征并没有依地理距离而聚类。     

Fluoxetine regulates hippocampal synaptic plasticity in CUMS depression rats

AIM: To investigate the role of fluoxetine in the hippocampal synaptic plasticity in chronic unpredictable mild stress (CUMS) depression rats and its effect on mTOR and autophagy signaling pathways. METHODS: Male Sprague-Dawley rats (n=60) were randomly divided into normal control group, CUMS group and fluoxetine group. The CUMS rat model was established through CUMS combined with solitary raising, and fluoxetine (20 mg·kg^-1·d^-1) was administered via intragastric gavage. The changes of body weight, the ratio of sugar intake and the results of the behavioral test were recorded to identify the modeling. Moreover, the expression of synaptic plasticity-related proteins glial fibrillary acidic protein (GFAP) and synaptophysin (SYP), apoptosis-related proteins Bcl-2 and caspase-3, mTOR signaling proteins mTOR and 4EBP1, and autophagy-related proteins beclin 1 and LC3 were examined by RT-PCR and Western blot.RESULTS: Compared with control group, the body weight, sucrose intake, and total distance and intermediate residence time in the open field test were significantly decreased in CUMS group. The results of RT-PCR and Western blotting showed that the mRNA and protein levels of SYP and GFAP in CUMS group were significantly down-regulated compared with control group. The expression of Bcl-2 in CUMS group was downregulated, while the protein level of cleaved caspase-3 increased. Decreased phosphorylation levels of mTOR and its downstream target molecule 4EBP1 were observed in CUMS group. Besides, the autophagy-related proteins beclin 1 and LC3 were significantly upregulated at mRNA and protein levels. All these results(upregulation or downregulation) were attenuated by the treatment with fluoxetine, and the difference was statistically significant. CONCLUSION: Fluoxetine might improve hippocampal synaptic plasticity and alleviate symptoms of depression by supressing apoptosis/autophagy signaling pathways and upregulating mTOR signaling pathway.     

羊草形态及生物量分配可塑性对土壤供磷能力的响应研究

植物形态及生物量分配变化是天然草原退化过程中的主要表现之一,通过研究植物形态及生物量分配对环境的响应规律有助于揭示草原退化及植被演替的内在机理。本试验研究了羊草形态、生物量累积及分配对土壤供磷能力的可塑性响应。试验采用有效磷含量低于3mg P_2O_5/kg的土壤设置0,30,90,180mg P_2O_5/kg 4个磷肥添加梯度,形成4种具有不同供磷能力的土壤,用于对羊草植株的培养,并于后期进行各项指标的测定。结果表明,1)土壤供磷能力的减弱明显减小了羊草的株高、各构件生物量,表现为高磷添加量显著高于低磷添加量,株高、叶生物量、茎生物量、根生物量、总生物量的降低幅度分别达到了14%,50%,51%,79%,63%。2)羊草个体形态及生物量分配对土壤供磷能力的响应并不完全一致,生物量累积对供磷量的敏感度最大,生物量分配次之,形态的敏感度最差,可塑性指数分别为0.58,0.31,0.19;单个性状指标以根干重最为敏感,可塑性指数达到了0.79。3)相关分析表明,羊草地上干重与叶宽、节间数、株高达到了极显著水平,此3个形态指标对羊草地上生物量的贡献率分别为30%,27%,26%,是形态指标中解释羊草地上生物量产生差异的主要因子。本试验在课题组前期研究的基础上,进一步从个体水平上探索羊草对土壤供磷能力的响应,与课题组前期试验结果相结合,可有助于探索天然草原退化和植被演替的内在原因。     

Repeatability of different stability parameters for grain yield in chickpea

The presence of genotype × environment (GE) interactions in plant breeding experiments has led to the development of several stability parameters in the past few decades. The present study investigated the repeatability of these parameters for 16 chickpea (Cicer arietinum L.) genotypes by correlating their estimates obtained from extreme subsets of environments within a year and also over years. Based on the estimates of response and stability parameters within each trial, the ranking of genotypes in the low-yielding subset differed from that in the high-yielding subset. This indicates poor repeatability for response and stability parameters over the extreme environmental subsets. The estimates of mean yield and stability parameters represented by ecovalence, W²_i, were consistent over years, whereas those of response parameters (b_i, and S²_i) showed poor repeatability. Our results suggest that single-year results for yield and stability can be used effectively for selecting cultivars with stable grain yield if tested in a wider range of environments.     

益智种质资源表型性状的遗传多样性分析

对收集的90份益智种质资源的18个表型性状进行遗传多样性分析,以期为益智品种改良和种质创新提供依据.结果 表明:供试的益智种质具有丰富的遗传多样性,质量性状中多样性指数最高的为果形(1.1507),数量性状中多样性指数最高的为株高(2.0700),变异系数最大的为结果枝数(41.32％);提取的6个主成分累计贡献率为6...     

台湾桂竹高产稳产密度效应的研究

本文应用台湾桂竹产区内２３６块丰产林标准地材料配制出竹林密度效应模型Ｗ＝０．０９７５５５Ｎ１．１６４３４４Ｄ１．８７７７６５,相关系数Ｒ＝０．９８,Ｆ检验值为１０８,偏相关系数Ｒ１＝０．９２,Ｒ２＝０．５８,检验结果达到极显著相关,对该模型进行生产弹性分析,边际产量分析,结果表明它可为现有台湾桂竹林的经营管理、竹林密度调整提供的理论依据．     

Temperature and food‐level effects on reproductive investment and egg mass in vendace,Coregonus albula

Abstract Individual variation in reproductive investment is important for recruitment and population dynamics in fish populations. Thus, it is crucial to understand how these decisions are influenced by environmental conditions. Here, the influence of growth variation during gonadogenesis or early life on reproductive investment in vendace, Coregonus albula (L.) was investigated. A set of cohorts of mature females were sampled over two different years with contrasting climate conditions and food levels, using total length at age 1 year as a proxy for juvenile growth. Relative reproductive investment and individual egg mass were lower in the favourable year (elevated temperatures and zooplankton densities) when the females were in better condition compared with a less favourable year (lower temperatures and zooplankton densities). Female vendace demonstrated plasticity in their allocation to relative reproductive investment and egg mass, probably induced by diverging environmental conditions. This phenotypic response to growth may have strong effects on recruitment and population growth rate.     

日本囊对虾早期生长性状遗传参数估计

基于68个日本囊对虾(Marsupenaeus japonicus)全同胞家系,采用混合线性模型和约束极大似然法对日本囊对虾生长性状进行遗传参数的估计。结果表明:1)45日龄、75日龄体长性状的遗传力估计值分别为0.1545±0.0505、0.1933±0.0475,腹节长性状的遗传力估计值分别为0.1672±0.0473、0.1937±0.0468,体重性状的遗传力估计值分别为0.1934±0.0439、0.1992±0.037,均为中等遗传力;2)不同日龄下日本囊对虾生长性状间的表型相关与遗传相关均为高度正相关,45日龄体长–腹节长、体长–体重、腹节长–体重的表型相关为0.7121±0.0188、0.5147±0.0277、0.5052±0.0280,遗传相关为0.9896±0.00340、0.9304±0.0321、0.9429±0.0301,75日龄体长–腹节长、体长–体重、腹节长–体重的表型相关为0.6710±0.0236、0.6555±0.0181、0.6534±0.0160,遗传相关为0.7637±0.0161,0.7479±0.0148,0.7177±0.0131。本研究表明对日本囊对虾生长性状进行选择是有效的,以体长、腹节长、体重任一性状作为指标进行选育均可达到生长改良的目的,本研究结果可为日本囊对虾的早期选择育种和多性状选择提供数据参考。