作 者 ：Xi Yi-Zhen
期 刊 ：植物分类学报 1986年 6期
Keywords:Pollen morphology, Podocarpaceae, Podocarpus, Dacrydium, Ultrastructure,
Abstract:
The pollen morphology and ultrastructure of exine of Podocarpaceae in China
were examined with light microscope, scanning electron microscope and transmission electron
microscope. The pollen grains of Podocarpus have rather large and prominent sacs on both
sides of body, and are 53.9-74.8 μm long in total, with their bodies 29.6-45.2 μm long and
19.1-31.3 μm wide. The sacs are smooth on outer surface with perforation, but reticulate insi-
de. On distal view, they are obviously of radial muri from its base. The body is oblate or
spheroidal, laddershaped on distal face. The exine of the capis tuberculate, but more distinct-
ly on the margin than in the centre. The pollen grains of Dacrydium are of small and indis-
tinct sacs around body, which are composed of many small bladders. The body is subcircular
in outline. Both body and sacs are irrugulate tuberculate under SEM. Examination of thin
sections of Podocarpus macrophyllus var. maki with TEM reveals that the exine includes ecte-
xine and endexine. It is interesting to note that foot layer of ectexine possesses lamellar stru
cture, but endexine is homogeneous in structure and lighter in colour. This character is speci-
fic in the gymnosperms. Based on informations of fossil pollen grains, Podocarpaceae is rather primitive and of ancient origin.