Reproduction

Terms to know for Dicentra formosa reproduction:
Alternation of Generations- a life cycle in which there is both a multi-cellular diploid form, the sporophyte, and a multi-cellular haploid form, the gametophyte
Gametophyte- the multi-cellular haploid form that produces haploid gametes by mitosis 
Sporophyte- the multi-cellular diploid form that results from the union of gametes, it produces haploid spores by meiosis that develop into the gametophyte
Heterosporous- a term referring to a plant species that has two kinds of spores: microspores and megaspores
Microspore- a spore from a heterosporous plant species that develops into a male gametophyte
Megaspore- a spore from a heteropsorous plant species that develops into a female gametophyte

In figure to the left, it shows a heterospore plant with microspores and megaspores.
Definitions from Campbell, "Biology", 8th Edition

 

Just like every other plant, Dicentra formosa (Pacific Bleeding Heart) reproduces by alternation of generations. Unlike meiotic and zygotic fertilization, alternation of generations has both a multi-cellular diploid and haploid phase. Alternation of generations is a complex life cycle starting with the zygote of the plant. The zygote, or the juvenile plant, grows into the adult sporophyte by mitosis. From here, the sporophyte generates spores via meiosis that will grow into gametophytes. In the Pacific Bleeding Heart, the sporophyte produces two types of spores, which makes it a heterosporous plant. The two spores are called microspores and megaspores.

The microspores grow into the male gametophyte, and the megaspores grow into the female gametophyte; both grow via mitosis. In the gametophyte, haploid gametes are produced by mitosis and each produces its corresponding gametes (male gametophyte produces male gametes and female gametophyte produces female gametes). Once produced, the gametes fertilizes to create a diploid zygote.

Since spores are not motile, pollinators are needed to spread the spores in order for them to grow into gametophytes and fertilize. These pollinators include insects, rain, and wind. However, the most important of these are the insects. The insects spread the spores by landing on the anther (microsporangium) and ovary (megasporangium) of the flower getting spores stuck to their legs and mixing the different spores together. The spores then fall off of the insects, land, and grow into gametophytes. When the gametes fertilize, a germinating seed is produced in the pods of the flowers and, with the help of ants (read more in interactions), the seeds are distributed across the land.  

 

 

 

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