Life Cycle and Development

The thalloid liverwort Marchantia can reproduce either asexually or sexually, allowing it to proliferate in various environmental and seasonal conditions. To reproduce asexually, liverworts utilize structures called gemma cups. Small, lenticular pieces of plant tissue called gemma reside in these cuplike structures and are released by the splashing of drops of water. The gemma that is subsequently released is able to sprout rhizoids and form a new thallus that is genetically identical to the parent thallus. This method of reproduction works well in moist conditions.

To reproduce sexually, structures called gametangiophores sprout from the thallus. Since liverworts are dioecious, separate male and female thalli function in reproduction. The male thallus bears antheridiophores (stalks with antheridia, the male sex organs), and the female thallus bears archegoniophores (stalks with archegonia, the female sex organs). The antheridia produce flagellated sperm that travel into the archegoniophore and fertilize the egg, thereby forming a diploid zygote.

Reproductive gametophyte plants

Photo courtesy of http://www.science.siu.edu/bryophytes

Life Cycle of the thalloid liverwort Marchantia

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