克隆植物野牛草对异质营养的表型可塑性响应

本实验以匍匐茎型克隆植物野牛草为材料,通过测定其在同质营养和3个斑块尺度的异质营养条件下生长指标、形态指标和叶绿素荧光参数的变化,研究野牛草对异质营养的表型可塑性反应。野牛草在尺度为25cm×25cm异质营养条件下会产生更多的分株、丛和分枝,积累更多的生物量,具有较高的Fv/Fm和ΦPSⅡ,生长状况要好于其他营养条件,但根系长度和间隔子长度并没有明显的变化。结果表明,生理整合调控了野牛草的表型可塑性,提高了母株的叶绿素荧光特性,增加了克隆分株对养分的吸收、利用能力,使野牛草在异质营养条件下的生长状况好于同质营养条件,特别是在尺度为25cm×25cm的异质营养条件下效果更为明显。

生理整合对营养分布格局下野牛草相连分株PSII叶绿素荧光参数的影响

本文以匍匐茎型克隆植物野牛草的克隆分株片段为材料,研究营养分布格局和生理整合对克隆植物野牛草叶绿素荧光参数的影响。结果表明,同质营养条件下,叶绿素荧光参数Fo、Fm、Fv/Fm、ΦPSⅡ和qP在相连分株间无显著差异,姊株叶片NPQ显著高于妹株。异质营养条件下,高营养斑块居中放置时,姊株叶片Fo、Fm、Fv/Fm、ΦPSⅡ和qP显著降低,而妹株叶绿素荧光参数则显著提高;高营养斑块居基放置时,姊株Fv/Fm、ΦPSⅡ和qP略有下降,Fo和Fm无明显变化,但妹株Fo和Fm则显著提高;高营养斑块居顶放置条件下,姊株叶片Fo、Fm、Fv/Fm、ΦPSⅡ和qP均高于妹株,NPQ则显著低于妹株。这说明,在资源有限条件下,基于"成本-收益"原则,野牛草相连姊株通过维持或者自抑制其光合效率,并提高妹株光合能力来增强克隆片段对异质营养环境的适应能力。本研究为进一步揭示生理可塑性对异质生境的响应机理以及探讨生理整合对生理可塑性的修饰机制提供了重要的理论依据。

Spatially Different Nutrient Histories Recorded by Multiple Cores and Implications for Management in Taihu Lake, Eastern China

The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional freshwater supply of a large population.Although efforts have been made to assess the nutrient evolution histories in the northern bays,little is known regarding nutrient histories in different parts across the entire lake basin.In this paper,we present nutrient histories for different parts of the lake based on chironomid transfer functions applied to four short cores obtained from the northern,western and eastern regions of the lake.The chironomid-inferred total phosphorus(CI-TP) concentrations were compared with the phosphorus concentrations obtained by using instrumental and sedimentary data.The results suggest that trophic evolution histories were asynchronous throughout the lake during the past decades in response to different ecological regimes controlled by the nutrient input,wind direction and shoreline topography.The restoration of aquatic plants may be an effective option for the management of lake rehabilitation to ′natural′ conditions.Given the multiple factors controlling the biotic communities in such a large and complex lake,combined analyses among the multi-proxies encountered in the sediments are necessary for comprehensive insight into paleolimnological studies.The spatial heterogeneity in the ecological trajectories within this complicated ecosystem suggests that different management practices should be undertaken for specific lake zones in the Taihu Lake.

Whole-exome sequencing identified compound heterozygous variants in MMKS in a Chinese pedigree with Bardet-Biedl syndrome

Bardet-Biedl syndrome(BBS) is a genetically heterogeneous disorder characterized by retinal dystrophy, polydactyly, obesity,developmental delay, and renal defects. At least 21 candidate BBS-associated genes(BBS1-19, NPHP1, and IFT172) have previously been identified, and all of them play important roles in ciliary function. Here, we collected a BBS pedigree with four members and performed whole-exome sequencing on the proband. The variants were analyzed and evaluated to confirm their pathogenicity. We found compound heterozygous variants(c.1192C>T, p.Q398* and c.1175C>T, p.T392M) in MKKS in both the siblings, and these were likely to be pathogenic variants. We also found a missense variant(c.2029G>C, p.E677Q) in NPHP1 and a missense variant(c.2470C>T, p.R824C) in BBS9 in the proband only, which are variants of uncertain significance. The compound heterozygous variants were probably responsible for the BBS phenotype in this Chinese pedigree and the missense mutations in NPHP1 and BBS9 might contribute to the mutation load.

Linking the spatiotemporal variation of litterfall to standing vegetation biomass in Brazilian savannas

Aims Litterfall at a global scale is affected by climate,edaphic features and vegetation structure,with litter production increasing from grasslands to forests following the rise in standing biomass.However,at landscape scales,the same relationship between litter production and vegetation structure has rarely been studied and comparisons of litterfall patterns between adjacent,structurally distinct communities are lacking.Here,we use a standardized methodology to describe the structural differences among four savanna physiognomies and analyze their relationship with changes in litterfall across the Cerrado.Methods We evaluated the woody vegetation structure and composition in 48 sites,equally distributed across four physiognomies and monitored the monthly litter production from April 2014 to March 2015.Important Findings Results showed that the density,basal area,cylindrical volume and aboveground biomass of woody vegetation differ among physiognomies,increasing consistently from cerrado ralo,cerrado típico,cerrado denso and cerradão.Indeed,we found a strong and positive relationship between aboveground biomass and annual litter production,with litter yield increasing from 0.9 to 8.4 Mg ha^(−1)across different physiognomies,following the increment in vegetation structure.Monthly production was seasonal and similar among vegetation types,increasing during the dry season.Leaves comprised the dominant fraction(approx.85%)and litterfall seasonality primarily resulted from the concentration of leaf shedding during dry months.However,the temporal pattern of litterfall throughout the year showed a gradual reduction in the seasonality from open to closed vegetation types,likely following the decrease of deciduous species abundance in the plant community.Our results showed that changes in vegetation structure may affect spatial and temporal litterfall patterns in different physiognomies,which co-occur across the Cerrado landscape,with potential implications for the overall functioning of this ecosystem.Moreover,these findings highlight the use of standardized methods as essential to correctly compare litterfall patterns among different environments.