13 resultados para Fish taxonomy
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
Saprolegnia brachydanis is described from zebra fish (Brachydanio rerio) in Wuhan, Hubei Province, China. The species is illustrated and compared with other species of the genus. The distinctive characteristics of S. brachydanis are the production of glomerulate oogonia wrapped around by predominantly monoclinous antheridia which can be up to eight in one oogonium. The oogonial stalks are short, straight, or curved and the antheridia, twisted, can enwind one or more oogonia. The oospores cannot mature or easily abort. Morphological features of the oomycete and the ITS sequence of its rDNA as well as the comparison with related species are discussed in this article.
Resumo:
A depth-integrated two-dimensional numerical model of current, salinity and sediment transport was proposed and calibrated by the observation data in the Yangtze River Estuary. It was then applied to investigate the flow and sediment ratio of the navigati
Resumo:
作者通过实地调查，栽培观察，大量查阅标本，对国产贝母属(Fritillaria L.)的形态性状作了深入的分析，认为贝母属中植株大小，茎生叶先端卷曲与否，花的数目、花梗的长短、花被片颜色等性状易受生境的影响;而鳞茎所具鳞片的数目，植株最下一轮叶的形状及排列，花部蜜腺的形状，花柱柱头的分裂程度，雄蕊花丝在发育完后的长短，蒴果的形状等性状受生境的影响较小，但在栽培情况下，这些性状有时也会发生变化．此外，作者首次报道了部分国产贝母属种类的核型和花粉形态．在此基础上对我国贝母属进行了系统整理，将正式发表的138个分类名称（包括80个种、52个变种、5个变型、1个栽培变型）归并成24种l变种，并对国产贝母组(Seclion Fritillaria)的种间关系作了初步探讨;同时，对该属的次级分类也作了修订．根据有关，F.karelinii花粉学和细胞学资料，以及邻近4个种的形态特征及分布特点，我们支持J.G..Baker(1874)的观点将该类群保留在贝母属内而不同意A.S.Lozin-Lozinskaya(1935)，A.Takhtajan(1987)将其单立成属也不同意W.B.Turrill &J.R.Sealy(1980)将其并入贝母组(Sect.Fritillaria)，而将该类群做为贝母属中的一个新组——砂贝母组(Sect.Rhinopetalum (Fish. ex Alex.) Y.B.Luo)．并认为该组与贝母组关系较近．作者通过上述工作及查阅世界各地有关贝母属的文献，认为贝母属内最原始的类群是Sect. Fritillaria，而Sect.Petillium，Sect.Rhinopetalum和Sect.Theresia是演化水平中等的类群．Sect.Liliorhiza则是演化水平最高的一类．通过对该属组(Section)级及种级分布式样的分析，认为伊朗一土兰区不仅是组的多度中心，并且也是多样化中心;在种级水平上，地中海区是分布的多度中心，而种级多样化中心则在伊朗一土兰区;此外，在伊朗一土兰区还保留着一些较原始的类群，因而，该区可能是贝母属的起源中心，最后，作者对贝母属的起源时间、散布途径及现代分布格局形成的原因进行了初步探讨．
