geeta at life.cc.sunysb.edu
Fri Nov 21 17:39:35 EST 1997
Dr. Magaly Rincon (frinconm at NEXUS.MWSU.EDU) wrote:
: In tetrasporic embryos (e.g., Lilium), the polar nuclei is tetraploid.
: During fertilization one sperm fuses with the polar nuclei and one with the
: egg. This means then that the endosperm is pentaploid. Is this
: interpretation correct?
Embryo-sacs (ie the female gametophyte) are tetrasporic. This means that
no cells walls form after either Meiosis I or II. This results in a single
megaspore that contains four haploid nuclei. In Lilium each of these
nuclei divides once mitotically, to form an 8-nucleate gametophyte
The two polar nuclei are each haploid, so after fusion with one haploid
sperm nucleus from the pollen, the endosperm nucleus that forms is
More information about the Plant-ed