Reproduction

Reproduction

Probably not what you were expecting but still extremely interesting!!

Mastocarpus papillatus reproduces sexually.  The reproductive cycle of Mastocarpus papillatus may be triggered by factors such as day length.  In sexual reproduction, Mastocarpus papillatus exhibits a three-phase life cycle that has an alternation of generation. It exhibits a dominant gametophyte generation.  There are separate male and female plants that produce haploid gametes. After release of male sperm, it is carried by the water column to receptive female hairs called trichogynes. Now that the male sperm is attached, it undergoes a cycle of nuclear division (mitosis) without the cell dividing. A fertilization pore is created between the spermatium and the trichogyne.

    

Reproduction in this red algae is unique since no flagellated stages are ever formed. It is generally assumed that the various reproductive spores are inert. The spores however are still actively motile due to gliding or amoeboid activity. The gametes are characterized as non-flagellated. Therefore, Mastocarpus papillatus is dependent on water columns for fertilization to occur. The gametes become fertilized and grow into a separate generation called a tetrasporophyte. The tetrasporophyte generation is capable of asexual reproduction even though the organism prefers to reproduce sexual. The tetrasporophyte generation sometimes looks exactly identical to the male and female gametophytes that originally produced it. This is knows as an isomorphic alternation of generations. However, in some occasions the tetrasporophyte can look completely different and form a thin felt-like crust on the sea bed called a Petrocelis phase. This process is known as a heteromorphic alternation of generations. The tetrasporophyte then produces tetrasporangia (by meiosis resulting in four 1n spores) that are released into the water column to germinate and complete the cycle.

Other Images of Life Cycle Stages

 

 

Female Gametophyte

You can see the many little papillae present in this image. Papillae is where fertilization occurs so these papillae are only present  on the female gametophyte.

 

 

 

 

Upright Petrocelis Stage

This sprouts from the encrusted Petrocelis stage.  This gets knocked off the substrate by powerful waves so a brand new Mastocarpus papillatus can form.

 

 

 

 

Encrusted Petrocelis Stage

This stage looks like tar!  You can understand why scientist use to think the two Petrocelis stages where two different species.  This encrusted stage gives rise to the upright stage and can stay stuck to the substrate for years.

 

 

You know all about how Mastocarpus papillatus reproduces safely, but if don't practice safe sex yourself, you will be very interest to learn about the Medicinal Uses of Mastocarpus papillatus!

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