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- Receptacles of bladderwrack, Fucus vesiculosus
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- Cut from receptacle showing oogonia (green peas). This is a female seaweed.
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- Cut male receptacles in a beaker. The orange that comes out of the conceptacles (pores) are sperm.
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- Two oogonia are opening up, setting their 8 eggcells free. The eggs have a perfect round shape, three can be seen slightly out of focus. Fucus eggs are negatively buoyant, wich means that they will sink down to the sea floor when they are released into the water column.
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- The egg-shaped form in the bottom of the picture is an unopened oogonia, which is a sack (made of sugar) containing 8 eggcells. Above can be seen an oogonia opening up and the tightly packed eggs are beginning to swell up to their perfectly round form, as those seen to the left in the picture.
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- Fucus egg made to appear blue by colouring it with calcofluorwhite and then use an UV microscope. The dark dots surrounding the egg are sperm trying to penetrate the already fertilized egg.
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- After gamete release, some receptacles swell up and look like small, warty balloons. This increases the buoyancy of the bladderwrack even more.
Baltic Sea Weed Blog 