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Question
In Dryopteris, the opening mechanism of sporangium is effectively operated by
In Dryopteris, the opening mechanism of sporangium is effectively operated by
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Solution
The correct option is C Stomium
When the capsule of the sporangium in Dryopteris matures, about 4 lower median cells of the jacket stretch tangentially. The two median ones identify the place from where the capsule opens. This is called as stomium. The other cells of the jacket develop a thickening. At maturity the indusium dries exposing the sorus. Due to loss of water in the annulus, the upper walls contract and inner ones straighten, the annulus coils. This feature exerts pressure on the wall resulting in the breaking of the capsule, between the cells of the strontium, thereby, releasing the spores.Hence the correct option is B.
When the capsule of the sporangium in Dryopteris matures, about 4 lower median cells of the jacket stretch tangentially. The two median ones identify the place from where the capsule opens. This is called as stomium. The other cells of the jacket develop a thickening. At maturity the indusium dries exposing the sorus. Due to loss of water in the annulus, the upper walls contract and inner ones straighten, the annulus coils. This feature exerts pressure on the wall resulting in the breaking of the capsule, between the cells of the strontium, thereby, releasing the spores.
Hence the correct option is B.
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