作 者 ：SUN Kun, CHEN Jia-Kuan, ZHANG Zhi-Yun
期 刊 ：植物分类学报 2001年 1期
Keywords:Najadaceae, Zannichelliaceae, Pollen morphology,
Abstract:
In the aquatic order Najadales, severe structural reduction, particularly the floral struc-
ture reduction, and strong convergence of morphological characters occurring in the Najadaceae and
Zannichelliaceae have greatly obscured their phylogenetic relationships and presented systematists
with difficult problems in understanding their phylogenetics. To gather more basic phylogenetic in-
formation regarding Najadaceae and Zannichelliaceae, pollen morphology of 4 genera of these two
families was examined with light microscope (LM), scanning electron microscope (SEM) and trans-
mission electron microscope (TEM). Our results provide the following insights: (1) Pollen grains of
Zannichelliaceae are inaperturate, subspheroidal or subprolate, with ornate or reticulate exine sculp-
turing. Pollen grains of Vleisia and Zannichellia are smaller, usually with ornate sculpturing, while
those of Lepilaena are larger, with crispate, ornate or reticulate sculpturing. (2) Pollen grains of
some species, e.g. Najas oguraensis Miki and N. flexilis (Willd.) Rostk. et Schmidt. in Naja-
daceae, are monosulcate, but in some other species studied here they are inaperturate. Pollen grains
of this family usually have not exine sculpturing, but those of N. oguraensis Miki and N. flexilis
(Willd.)Rostk et Schmidt have verrucate or granular sculpturing. (3) Evidence from the aperture,
wall sculpturing and structure of pollen grains does not support the viewpoint that Najadaceae is
closely related to Zannichelliaceae and Potamogetonaceae, but shows that Zannichelliaceae and Pota-
mogetonaceae are near relatives.