合果木属和观光木属的花粉形态

合果木属合果木（Ｐａｒａｍｉｃｈｅｌｉａｂａｉｌｌｏｎｉｉ（Ｐｉｅｒｒｅ）Ｈｕ）和观光木属观光木（ＴｓｏｏｎｇｉｏｄｅｎｄｒｏｎｏｄｏｒｕｍＣｈｕｎ）的花粉，在光镜和扫描电镜下形态较相似。但在透射电镜下，两者差异较大：合果木花粉外壁的覆盖层、往状层和基层的分化不明显，柱状层小柱极少，虽有颗粒分化但数量不多；观光木花粉外壁三层的分化较明显，柱状层中已出现较多典型的颗粒和小柱。据此，合果木的花粉壁在木兰科中应属较原始的类型，而观光木的则属该科中较进化的类型。两者在花粉壁结构上的差异可为二属的分立提供花粉学上的证据。

POLLEN MORPHOLOGY OF PARAMICHELIA AND TSOONGIODEDRON FROM CHINA

This paper reports the pollen morphdogy of Paramichelia baillonii,as the only representativeof the genus from China and Tsoongiodendron odorum, the species of the monotypic genus,Thepollen grains of the 2 species show similariries under the LM and SEM,But the study under TEMshows differences of the 2 species:(1)The exine of T.odorum can be clearly distinguished into 3layers:tectum,bacula and footlayer,in contrast 3 layers of that in P,baillonii are obscurely recog-nized.(2)There are many typical columelae and spheroidal bodies in bacula in T,odorum,but fewcolumellae and some spheroidal bodies with untypical appearance in that of P.baillonii. According tothe differences,the authors conclude that the ultrastructure of pollen wall of P,baillonii belongs tothe primitive type whereas that of T,odorum belong to the advanced one in Magnoliaceae,Thevariat ions of the exines of the 2 species also provide palynological evidences to separate these twogenera.