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In gymnosperms, the pollen chamber represents
A
a cavity in the ovule in which pollen grains are stored after pollination
B
an opening in the megagametophyte through which the pollen tube approaches the egg
C
the microsporangium in which pollen grains develop
D
a cell in the pollen grain in which the sperms are formed
Detailed Solution
In gymnosperms the ovules are naked, and the pollen grains are carried by wind directly to the micropyle of the ovule.
At the micropylar end, some cells of the nucellus break down to form a small cavity called the pollen chamber.
The pollen grains are drawn into the ovule with the pollination drop and come to rest in this pollen chamber, where they are stored after pollination.
They stay there for some time and then germinate, forming pollen tubes that grow through the nucellus towards the archegonia.
So the pollen chamber is a part of the ovule (megasporangium), not of the microsporangium; the microsporangium is the pollen sac in which the pollen grains develop.
It is also not an opening in the female gametophyte, and not a cell of the pollen grain.
So the pollen chamber represents a cavity in the ovule in which pollen grains are stored after pollination.
At the micropylar end, some cells of the nucellus break down to form a small cavity called the pollen chamber.
The pollen grains are drawn into the ovule with the pollination drop and come to rest in this pollen chamber, where they are stored after pollination.
They stay there for some time and then germinate, forming pollen tubes that grow through the nucellus towards the archegonia.
So the pollen chamber is a part of the ovule (megasporangium), not of the microsporangium; the microsporangium is the pollen sac in which the pollen grains develop.
It is also not an opening in the female gametophyte, and not a cell of the pollen grain.
So the pollen chamber represents a cavity in the ovule in which pollen grains are stored after pollination.