STUDIES ON THE POLLEN MORPHOLOGY OF ALISMATACEAE,HYDROCHARITACEAE,POTAMOGETONACEAE AND NAJADACEAE IN HUBEI PROVINCE

Very rare studies of the pollen morphology in Chinese Helobiae have been carried out The pollen morphology of 29 species, 1 variety and 1 form belonging to 11 genera of Alismataceae, Hydrocharitaceae, Potamogetonaceae and Najadaceae in Hubei Province, China (additionally Lagarosiphon alternifolia growing in Zhanjiang) were investigated in the paper with the aid of light microscope and SEM. The following results were obtainedt: The pollen grains of Alismataceae have many round apertures (pantotreme), their exine surface is ornamented with spinules and those of Najadaceae are distal-monosulcate, their exine surface is rugulate. The pollen grains of 6 genera in Hydrocharitaceae and 2 genera in Potamogetonaceae are inaperture, the former's exine surface are mainly spinulate and the latter reticulate. The relationships among the taxa were discussed according to the pollen morphology in the paper: 1. In the four families, Najadaceae is the most primitive, Alismataceae and Potamogetonaceae are more advanced than Hydrocharitaceae. 2. Both of Alisma and Caldesia are more primitive than Sagittaria, and Hydrilla is the most advanced in Hydrocharitaceae. 3. Subgenus Coleogeton is more advanced than Subgenus Eupotamogeton. 4. Najas foveolata has most primitive pollen grains in the genus. The views above agree with those obtained according to the features of the plants and their karyotypes. Additionally the authors investigated the methods for studying the morphology of pollen which is easily changed in form.