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Wolffia pollen are spherical with a diameter of ~16 microns, monoporate, and “echinate” with short spines (“spinules”) distributed randomly over the surface (Erdtman 1952, Kuoh et al. 2000). Pollen of Wolffia and all Lemnaceae (duckweed family) are trinucleate, considered to be an advanced form derived from ancestral binucleate pollen in more primitive members of Order Arales. Many or most plants with trinucleate pollen are self-incompatable (Brewbaker 1967). Brewbaker (1967) claims that underwater pollenation ocurs in Wolffia, although current observations of buoyant pollen call that into question. He also claims that the more primitive binucleate pollen are unable to germinate and grow in water or cultural solutions (Brewbaker 1957). |
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References: |
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Brewbaker, J. L. 1957. Pllen cytology and self-incompatability systems in plants. J. Hered. 48: 271-277. Brewbaker, J. L. 1967. The distribution and phylogenetic significance of binucleate and trinucleate pollen grains in the angiosperms. Amer. J. Bot. 54(9): 1069-1083. Erdtman, G. 1952. Pollen morphology and plant taxonomy. Almqvist & Wiksell, Stockholm, Sweden. Reprinted 1966, Hafner Publishing Company, New York and London. (557 pp.) Kuoh, C-S., M-J Yang and G-I Liao 2000. The flower structure and anther dehiscence of Wolffia arrhiza (Lemnaceae). Taiwania 45(1): 30 – 37. |
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