991 resultados para 154-928
Resumo:
麻黄属(Ephedra)起源较早,该属植物的形态性状极度退化或简化,可用于经典分类学的有价值的性状非常有限。分布于青藏高原的藏麻黄(E. saxatilis)和丽江麻黄(E. likiangensis)二者间形态相似,性状变异连续,很难分辨,但被《中国植物志》中、英文版作两个种处理。 本文对藏麻黄和丽江麻黄的七个居群、151个个体的叶、雌球花和节间长等形态学性状进行了分析,发现各性状的变异情况在群体间无明显差异。同时我们还对154个个体的叶绿体DNA trnT-trnF和 trnS-trnfM区进行了序列分析,两个片段的联合矩阵长1382bp,共有29个变异位点,其中有9个碱基变异和2个indel,可划分为H1、H2和H3三种单倍型。这3种单倍型在丽江麻黄中均有分布,但藏麻黄仅含H1和H2。 综合来自形态学和分子方面的证据,我们发现藏麻黄和丽江麻黄的关系非常近缘,因此建议予以合并。同时本文还以膜果麻黄(E. przewalskii)为外类群,从谱系生物地理学角度探讨了三种叶绿体单倍型的进化关系,发现H2最原始,分布最广;H1与其它两种单倍型间的序列差异较大,可能是较进化的类型。此外,无性克隆的繁殖方式可能是导致Ephedra单倍型非常简单的重要原因之一。
Resumo:
This report provides baseline biological data on fishes, corals and habitats in Coral and Fish Bays, St. John, USVI. A similar report with data on nutrients and contaminants in the same bays is planned to be completed in 2013. Data from NOAA’s long-term Caribbean Coral Reef Ecosystem Monitoring program was compiled to provide a baseline assessment of corals, fishes and habitats from 2001 to 2010, data needed to assess the impacts of erosion control projects installed from 2010 to 2011. The baseline data supplement other information collected as part of the USVI Watershed Stabilization Project, a project funded by the American Recovery and Reinvestment Act of 2009 and distributed through the NOAA Restoration Center, but uses data which is not within the scope of ARRA funded work. We present data on 16 ecological indicators of fishes, corals and habitats. These indicators were chosen because of their sensitivity to changes in water quality noted in the scientific literature (e.g., Rogers 1990, Larsen and Webb 2009). We report long-term averages and corresponding standard errors, plot annual averages, map indicator values and list inventories of coral and fish species identified among surveys. Similar data will be needed in the future to make rigorous comparisons and determine the magnitude of any impacts from watershed stabilization.