-
heterosporous life
cycles using microspores and
megaspores arose independently in
several plant groups during the
Devonian period.
Microspores are haploid, and are...
- Freeman. Ray, Ankita. "Structure of
Microspores and the
Development of Male
Gametophyte (=
germination of
Microspores)".
Archived from the
original on 8...
-
diploid microspore mother-cells,
which then
produce four
haploid microspores by meiosis.
These become pollen grains,
within which the
microspores divide...
- four
haploid microspores are
produced from each
diploid pollen mother cell,
after meiotic division.
After the
formation of the four
microspores,
which are...
-
produced internally, and the
megaspores (formed
within the ovules) and the
microspores are
involved in the
formation of more
complex structures that form the...
-
heterosporous (two
kinds of
spores are produced).: 18
These plants produce both
microspores and megaspores,
which give rise to
gametophytes that are functionally...
- meiosis,
whereas in
microsporogenesis all four
microspores survive. In gymnosperms, such as conifers,
microspores are
produced through meiosis from microsporocytes...
-
which are heterosporous,
microspores and
megaspores are dis****d from
sporangia either p****ively or by
active ejection.
Microspores produce microgametophytes...
- and
female cones. In the male cones,
microspores are
produced from
microsporocytes by meiosis. The
microspores develop into
pollen grains,
which contain...
-
distinct sizes (heterospory or anisospory):
larger megaspores and
smaller microspores. When the two
kinds of
spore are
produced in
different kinds of sporangia...
