Reconstruction of Terrestrial environment with using the internal anatomy of fossil plants.

本项目的主要目的是利用植物化石的内部解剖重建陆地环境，我们在中国东北地区的中生代沉积物中采集了一些裸子植物和蕨类植物化石。本文描述了采自辽宁侏罗纪的裸子植物新跃木。该标本的解剖特征显示出苏铁样和海鞘样的特征。自20世纪50年代以来，关于从海鞘类到苏铁类进化途径的假说一直在讨论中。然而，至今尚未发现将这两个类群联系起来的化石证据，因此该标本对重建裸子植物的进化史具有重要意义。并对河北中侏罗世的紫萁科蕨类植物进行了描述。该标本属于化石茎属Ashicaulis。通过对石茎属植物的标本采集和文献检索，发现该属植物仅在暖温带和冬季潮湿的气候条件下生长旺盛。因此，该属可作为古气候的指示植物。在蒙古，我们描述了古卓尔河盆地早白垩世的植物化石。我们描述了蕨类植物、石松类植物、马形目植物和针叶树。没有发现被子植物。根据这些大型植物化石记录和前人的孢粉学工作，我们重建了古乔依盆地的古植被。在白垩纪，盆地中部为蕨类沼泽，周围高地为针叶林覆盖。在现代对比的基础上，估算了该流域植被的自然初级生产力，重建了该流域古生态系统的能量流。

The main purpose of this project is the reconstruction of the terrestrial environment with using the internal anatomy of fossil plant remains.In north eastern China, We collect several gymnosperm and fern fossils from the Mesozoic deposits. We described gymnosperm trunk Xinxyueoxylon from the Jurassic of Liaoning Province. Anatomical features of this specimen show both cycad-like and medulosans-like characters. Hypothesis of the evolutionary way from medulosans to cycad have been discussed since 1950's. However, no fossil evidence which connects these two taxa have been found. Thus this specimen is important to reconstruct the phylogeny of gymnosperms. We also describe osmundaceous fern Stem from the middle Jurassic of Hebei province. This specimen belongs to the fossil stem genus Ashicaulis. Based on specimen and literature search of Ashicaulis species, we find that this genus is flourished only under the Warm temperate and Winter wet dimatic condition. Thus this genus can be used as a indicator of paleoclimate. Terrestrial climate of fossil sites may belongs to these climatic condition.In Mongolia, we described fossil plants from the lower Cretaceous of paleo-Choyr basin. We described ferns, lycopsids, equistetaleans, and conifers. No angiosperm was discovered. Based on both these mega fossil plants records and previous palynomorph works, we reconstruct the paleovegetation of paleo-Choyr basin. In the Cretaceous time, central part of this basin is fern marsh and surrounding highland is covered with conifer forests. We also estimate the natural primary product(NPP) of this vegetation based on modem counter part and reconstruct the energy flow of paleoecosystem of this basin.