Megasporangia:
Megasporagium is the structure which produces megaspores in plants. It
undergoes meiosis to produce haploid spores through a process known as megasporogenesis. In
seed plants, megasporangium is the ovule. The ovule is inside the ovary, which is the basal part
of the ‘stamen of the flower’ in angiosperms and the ‘female cone’ of the gymnosperms.
Structure of megasporangia:
The three structural parts of the ovule are integuments, nucellus, and the embryo sac.
Integuments are the outer layers of the ovule. Nucellus is the inner cell mass of the ovule,
comprising of diploid, sporophytic cells. It undergoes the normal functions of the
megasporangium. The megaspore mother cell in the middle of the nucellus undergoes
sporogenesis through meiosis. One of the four resultant cells can develop into the megaspore. It
is called the embryo sac in angiosperms and develops into mega gametophyte, the female
gametophyte.
Development of Megasporangia:
The megasporangium contains megaspore mother cells, which divide by meiosis to
produce haploid megaspores. A megaspore develops into a female gametophyte containing a
haploid egg. A new diploid sporophyte is formed when a male gamete from a pollen grain enters
the ovule sac and fertilizes this egg.
Megasporagium is the structure which produces megaspores in plants. It
undergoes meiosis to produce haploid spores through a process known as megasporogenesis. In
seed plants, megasporangium is the ovule. The ovule is inside the ovary, which is the basal part
of the ‘stamen of the flower’ in angiosperms and the ‘female cone’ of the gymnosperms.
Structure of megasporangia:
The three structural parts of the ovule are integuments, nucellus, and the embryo sac.
Integuments are the outer layers of the ovule. Nucellus is the inner cell mass of the ovule,
comprising of diploid, sporophytic cells. It undergoes the normal functions of the
megasporangium. The megaspore mother cell in the middle of the nucellus undergoes
sporogenesis through meiosis. One of the four resultant cells can develop into the megaspore. It
is called the embryo sac in angiosperms and develops into mega gametophyte, the female
gametophyte.
Development of Megasporangia:
The megasporangium contains megaspore mother cells, which divide by meiosis to
produce haploid megaspores. A megaspore develops into a female gametophyte containing a
haploid egg. A new diploid sporophyte is formed when a male gamete from a pollen grain enters
the ovule sac and fertilizes this egg.
