Pollen of pine is more than one cell, so it has had mitotic divisions
after the formation of the microspore formed by meiosis. Therefore, I
would not consider it to be a microspore any longer. I have heard it
considered a mature male gametophyte when it is ready to be shed. If we
consider a plant to be mature when the plant body is completely grown, but
before its gametes are produced, then this shed pollen is mature. If I
consider an analogy with bryophytes, there are those species that never
produce gametangia. Does this mean they are never mature? They continue
to reproduce asexually by growth and fragmentation or even gemmae.
Janice
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Janice M. Glime, Professor
Department of Biological Sciences
Michigan Technological University
Houghton, MI 49931-1295
jmglime at mtu.edu
906-487-2546
FAX 906-487-3167
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